The training report details a 23-week industrial training program at Colombo Dockyard PLC undertaken by W.A.C.S. Muthukumarana from August 1 to December 31, 2016. It includes an introduction to the company, a SWOT analysis, and comprehensive descriptions of various training locations, projects, and gained experiences. The report concludes with reflections on the overall usefulness and drawbacks of the training experience.

1. UNIVERSITY OF MORATUWA
FACULTY OF ENGINEERING
Non-GPA Module 3992 Industrial Training
TRAINING REPORT
Colombo Dockyard PLC
From 01/08/2016 to 31/12/2016
Date of Submission: 31/01/2017
Muthukumarana W.A.C.S.
130388X Department of Mechanical Engineering

2. i
Preface
This report contains the essence of the overall industrial training period of 23 weeks at
Colombo Dockyard PLC. The report comprises of three chapters including an introduction to
the training establishment, a detailed description on the nature of training undergone at the
training establishment and the conclusion. The first chapter provides information about the
training establishment along with a SWOT analysis and explaining its profitability. The second
chapter presents a detailed description of various training locations, knowledge and
experiences gained and projects undertaken during the training period. The sub-sections of the
second chapter have been allotted to provide details of training by mainly focusing on the
hands-on experiences, skills developed and additional knowledge gained from the workshops
and departments. The methodologies adopted in projects completed during the training period
are explained the last sub-section of chapter two. Three project reports have been annexed to
this training report. The final chapter is allotted to conclude the overall training experience
commenting on its usefulness and drawbacks.

3. ii
Acknowledgement
The overall success of the training period was achieved due to valuable contribution of various
persons.
I would like to express my heartfelt gratitude towards Mr. Ananda Gamage, head of the
Industrial Training Division, and Mr. Roy Sankaranarayana, senior lecturer at University of
Moratuwa. My utmost gratitude and respect goes to Dr. W.K. Wimalasiri, the head of
Mechanical engineering department and Dr. R.A.C.P. Ranasinghe for sparing their valuable
time in coordinating the training program on behalf of the department.
I would also like to thank Mr. K.K.M.H.W.S.P. Silva, the assistant manager of training and
development at Colombo Dockyard for being so flexible in matters related to training and
guiding us in every possible way.
My sincere thank is extended to all engineers and employees who were always there to assist
in technical aspects and for sharing their precious knowledge in the field. I would specially like
to thank Mr. R.K.A.G. Rathnayake, an engineer of hull construction department, Mr. D.G.C.A.
Rambukwella, the workshop engineer of engine-fitting shop and Mr. Asitha Bandara, design
engineer of design department for their tremendous support in completion of assigned projects.
I sincerely thank all colleagues who assisted me in every possible way to make industrial
training a success.
W.A.C.S. Muthukumarana,
Undergratuate,
Department of Mechanical Engineering,
University of Moratuwa.
31st
of January, 2017

4. iii
Contents
Preface.........................................................................................................................................i
Acknowledgement .....................................................................................................................ii
Contents ................................................................................................................................... iii
List of figures.............................................................................................................................v
List of tables..............................................................................................................................vi
1. Introduction to the training establishment..........................................................................1
1.1. Company profile..........................................................................................................1
1.2. Organizational structure and hierarchical levels .........................................................2
1.3. SWOT analysis for Colombo Dockyard PLC.............................................................3
1.3.1. Strengths .......................................................................................................3
1.3.2. Weaknesses...................................................................................................4
1.3.3. Opportunities ................................................................................................5
1.3.4. Threats ..........................................................................................................6
1.4. Profitability of the company........................................................................................7
2. Training Experience ...........................................................................................................8
2.1. Nature of training at Colombo dockyard.....................................................................8
2.2. Hull construction department....................................................................................11
2.2.1. Loft .............................................................................................................12
2.2.2. Steel workshop ...........................................................................................13
2.2.3. Line heating process ...................................................................................15
2.3. Safety department......................................................................................................17
2.3.1. Administrational control.............................................................................17
2.3.2. Engineering control ....................................................................................19
2.4. Plant shop..................................................................................................................20
2.4.1. Introduction to Plant shop...........................................................................20
2.4.2. Gas line system maintenance......................................................................21
2.4.2.1. Repairing method of a flash back arrestor ....................................21
2.4.2.2. Inspection of central gas storage...................................................22
2.4.3. Maintenance of airless spray painting machine..........................................23
2.5. Deck-fitting shop.......................................................................................................24
2.5.1. Functions of Deck-fitting shop...................................................................24
2.5.2. Repairing procedure for an anchor mooring winch....................................24

5. iv
2.5.3. Operation & testing of a Pressure-Vacuum valve ......................................25
2.6. Machinery outfitting..................................................................................................26
2.6.1. Exposure gained at the workshop...............................................................26
2.6.2. Flow rate testing of the ballast system........................................................27
2.6.3. Ultrasonic flow rate testing method............................................................28
2.6.4. Pipe fabrication...........................................................................................28
2.7. Engine-fitting shop....................................................................................................29
2.7.1. Introduction to Engine-fitting shop ............................................................29
2.7.2. Pressure testing of main engine cylinder heads..........................................30
2.7.3. Overhauling and pressure testing of heat exchangers ................................31
2.8. Machine shop ............................................................................................................33
2.8.1. Hands-on experiences in machining operations .........................................33
2.8.1.1. Fabrication of a hexagonal nut....................................................34
2.8.1.2. Fabrication of a pipe flange.........................................................35
2.8.2. Dynamic balancing of a rotor .....................................................................36
2.9. Foundry .....................................................................................................................39
2.9.1. Introduction to Foundry..............................................................................39
2.9.2. Casting a bronze ring using sand casting method........................................39
2.10. Design department...................................................................................................41
2.11. Projects undertaken .................................................................................................43
2.11.1. Safety helmet project..................................................................................43
2.11.2. Improvement of workshop lighting system................................................44
2.11.3. Ramp design project ...................................................................................45
3. Conclusion........................................................................................................................47
Annex 1 : Balance quality grades for rigid rotors……………………………………………………...vi
Annex 2 : Chart of permissible residual unbalance…………………………………………………...vii
Annex 3 : Piston pump ………………………………………………………………………………viii
Annex 4 : Project report on safety helmets………………………………………….…………………x
Annex 5 : Proposal for new lighting system………………………………………………………..xxiv
Annex 6 : Preliminary calculation report on ramp design………………………………………....xxxii

6. v
List of figures
Figure 1.1. Organizational structure of Colombo Dockyard PLC.............................................2
Figure 1.2: Financial statistics for the past ten years.................................................................7
Figure 2.1: Marking the curvature of a template used in metal forming .................................12
Figure 2.2: Functions of steel workshop..................................................................................13
Figure 2.3: CNC Plasma plate cutting machine.......................................................................14
Figure 2.4: Hydraulic press machine .......................................................................................14
Figure 2.5: Plate rolling machine.............................................................................................14
Figure 2.6: Plates formed by line heating ................................................................................16
Figure 2.7: Basic components of a flash back arrestor ............................................................22
Figure 2.8: Geometric details of pipe flange ...........................................................................35
Figure 2.9: Dynamically balancing an impeller of a blower ...................................................37
Figure 2.10: Pouring molten metal into the mould..................................................................40

7. vi
List of tables
Table 2.1: Training locations and time allocation. ....................................................................8
Table 2.2: Areas of specialization of training worksites............................................................9
Table 2.3: Details of key training personnel............................................................................10
Table 2.4: Heat line spacing details .........................................................................................15
Table 2.5: Results of Load-line survey....................................................................................42

8. 1
1. Introduction to the training establishment
1.1. Company profile
Colombo dockyard PLC (CDPLC) is a company that has gained its reputation in the
marine sector for ship building, ship repair and offshore engineering. The company also
provides general engineering services to serve various purposes. Throughout its
lifespan of more than 40 years, the company has evolved gradually to become a pioneer
in marine engineering services. Colombo Dockyard now operates in collaboration with
Onomichi Dockyard Co. Ltd based in Japan. 51% of the company shares are owned by
Onomichi Dockyard Company, 40% owned by local institutions and 6% owned by local
individuals as per the annual report for the year 2015.
The partnership with Onomichi Dockyard Company has paved the way for a flow of
Japanese technology in to Sri Lankan marine industry. Apart from ship repair and ship
building services, the company has also extended its scope to provide general
engineering services by establishing a company named ‘Dockyard General Engineering
Services’ (Pvt) Limited abbreviated as DGES (Pvt.) Limited company. This is a good
sign showing willingness of the company’s management for further expansion in to
other engineering sectors. Colombo Dockyard PLC also owns 51% of the shares of its
subsidiary company, ‘Ceylon Shipping Agency (Pte) Ltd’ based in Singapore.
Presidential exports awards for 2007 & 2008, ‘Business Today Top 20’ award in 2011,
‘Engineering Excellence’ award in 2011, NCE Export award in 2010 and being listed
in ‘Annual Forbes Financial Magazine’ are some of the best achievements made by the
company. Colombo Dockyard PLC has also been awarded with ISO 9001: International
Standards for Quality Management in the year 2010. As a company involved in the
marine industry, the company has given priority to safety management and has been
able to earn OHSAS 18001 certification for maintaining occupational health and safety.
Owing to its long history in the marine sector, Colombo Dockyard possesses a client
base throughout the world in countries like Singapore, India, Japan, Norway and
Greece. The company also provides its utmost service to the nation through ship repair
and ship building services offered to Sri Lankan Navy.
Colombo Dockyard currently operates with a skilled workforce of 1400 permanent
workers, and about 400 trainees serving at their best in order to cater to customers’
requirements efficiently.

9. 2
1.2. Organizational structure and hierarchical levels
The senior management team of Colombo Dockyard PLC comprises of five general managers,
and four assistant general managers working under the leadership Chief executive officer. The
role of management has been divided into several sections namely, ship building, production,
ship repair business, logistics, and human resources development and administration. Five
general managers have been appointed to bear responsibilities of these divisions. The
organizational structure becomes more complex in ship building and production division where
responsibilities further get divided among assistant general managers appointed for docks &
maintenance, new construction, and ship repair. The hierarchy gradually comes to head of
department, workshop engineer, engineer, foreman, supervisor and then to permanent worker.
The hierarchical levels of the organizational structure of Colombo Dockyard are shown in a
simplified form in figure1.1.
Figure 1.1. Organizational structure of Colombo Dockyard PLC

10. 3
1.3. SWOT analysis for Colombo Dockyard PLC
1.3.1. Strengths
Key strength of a company is its workforce and the success any establishment is a mere
reflection of the skills of its employees. Colombo Dockyard PLC possesses a skilled
workforce of 1400 permanent workers, 1300 sub-contractors and about 400 trainees. The
availability of low-cost labour supplied from Indian manpower companies has also
strengthened its workforce. The company is well reputed for the quality of training
provided to its welders, fabricators and fitters. Owing to knowledge gathered during its
40 years of history, Colombo Dockyard naturally inherits work specialization in ship
building sector. The knowledge and experiences of its employees in the field has always
been the company’s greatest strength.
Possession of work area and technology equipped with efficient machinery, equipment,
computer software, and incorporation of information technology can also be recognized
as a strength of the company. At present, Dockyard operates its ship building and ship
repair projects in 4 dry docks with capacities ranging from 8,000 DWT (Dead Weight
Tonnage) to 125,000 DWT. The company has the ability of handling most of the heavy
engineering services due to availability of heavy duty cranes (capacity up to 160 tons),
large workshops equipped with overhead cranes (ex:- engine-fitting shop), and facilities
for machining heavy machinery components. Security system, inventory management,
database of employees’ details, project details are all handled by computer management
systems that has enhanced overall efficiency of the company. Colombo Dockyard has
licensed access to CAD software such as ‘Ship Constructor’, and ‘Solidworks’ that have
been of immense use in the designing and planning process.
The strategic location of Colombo has always been a merit for Colombo Dockyard to
serve repairs of the vessels sailing across the Indian Ocean. Yet another strength is its
client base expanded over years of business relationships in ship building, ship repair and
offshore engineering. Dockyard’s prestige clientele is spread over various countries like
India, Singapore, Japan, Italy, Netherlands, France, Greece, Hong Kong etc.
As for any other company, Colombo Dockyard’s most vital strength is its financial
stability. According to the annual reports of past years, the company earns a total revenue
of 14 billion rupees on the average and a profit (after tax) of 300 million rupees. Colombo
Dockyard is in hold of total assets worth 17 billion rupees which confirms its financial
stability.

11. 4
1.3.2. Weaknesses
The most noticeable weakness of the company according to personal observations made
during the training period is the exploitation of resources and man power. Most of the
employees have gotten used to extend the duration of an assigned job intentionally
without being noticed by supervisors and engineers of the respective workshop.
Spending of working hours for activities other than the job (sleeping, watching TV, use
of mobile phones are examples) has become inevitable in certain workshops. This may
also occur due to lack of work assigned on employees.
The technology used in some workshops was outdated and hardly applicable to modern
requirements. For an example, Foundry workshop lacked requirements for die casting
and rubber moulding. The only casting process that could be satisfactorily performed
was sand casting. Most of the drag and cope boxes, patterns and cores used in the
foundry were old age and wasted due to corrosion. However, it possessed a skilled staff
with enough experiences and sound knowledge in the field. It should be noted that the
attention of the administration must be drawn towards technological development of
workshops as well.
Absence of research and development could become a massive blow against the growth
of the company in the marine industry where developments are being made every day.
Although research in naval architecture can be impossible initially, the company could
start by initiating research in manufacturing engineering, material science and machine
designing by utilizing its human resources. It should be understood that Sri Lankan
engineers are capable of doing more than documentation and man-power handling.
The lack of communication between personnel higher in the hierarchy and lower level
workers was a clear sign of weakness. This might be a common weakness in most
companies with such complex organizational structures. There has to be mutual
understanding between managers and workers in order to resolve common issues faced
by the company. In certain workshops it was evident that workshop engineers were
never consulted or they never involved even in serious technical matters. (Despite
workshops like the Plant shop where weekly meetings were held summarizing
workshop’s progress and future activities).

12. 5
1.3.3. Opportunities
Being one of the pioneering dockyards in South-Asia and being the only ship building
company in Sri Lanka, Colombo Dockyard has ample opportunities for growth. Having
no other competitor in the Island, the company has the opportunity to venture into other
coastal regions of the country. Other areas with a potential of accommodating a
shipyard are Trincomalee, Oluvil, and Point Pedro, while Trincomalee being a natural
harbor, will be a strategic location for operations.
Due to the collaboration with Onomichi Dockyard Co. Ltd in Japan, Colombo
Dockyard has the opportunity to seek technical guidance from Japan which is a country
renowned for its technology. Introduction of sophisticated machinery from Japanese
technology, overseas training programs for employees can be acquired as a result of
this partnership. This is an opportunity that most of the companies are deprived of.
There are opportunities in local level for heavy engineering services that are related to
oncoming projects attributed to Ministry of ports and shipping, Ministry of petroleum
resources development and Ministry of Mahaweli development as stated in the annual
budget 2016. Some of the projects are listed below.
 Moragahakanda Kaluganga development project (Completion of 90% of the
dam)
 Construction of East-container terminal of port of Colombo.
 Projects on refurbishment and expansion of refinery, Sapugaskanda
 Project on cross country pipe line improvement
 Project on construction of fuel hydrant system and other facilities at BIA,
Katunayake.
 Project on production and commercialization of discovered gas deposits in
Mannar basin
Increase in demand for offshore oil exploration in India, offshore platforms and
requirement for their repair facilities are some of the overseas opportunities available.

13. 6
1.3.4. Threats
The major threats to the company are rules and legislations set by the local government,
IMO (International Maritime Organization) and the classification societies that approve
ship building projects. Change of taxation policy of the government, changes in
currency rates, new environmental legislations set up IMO and restrictions made by
classification societies can produce a setback in the progress of an on-going project. As
an example, according to a press notice issued by the Finance ministry on 6th
of April,
2016, the company is liable to pay income tax at a rate of 17.5% but financial statements
had been prepared considering the current rate of 12%. Once a process has been fully
planned for a particular project, even the slightest change of policies will affect its
outcome.
Adverse global economic conditions that occur due to fluctuation of oil prices can have
a massive impact on Colombo Dockyard as a ship building company. The major threat
comes from ship building project cancellations. For an instance, the cancellation of one
ship building contract due to sudden drop in oil prices in 2015 resulted in a major loss
of more than 500 million rupees to the company. Financial threats are also faced due to
unpredictable changes in currency rates.
According to most of the shipping companies, the latest regulation enforced by the IMO
on sulphur content of heavy fuel oils (HFO) used in ships will greatly affect shipping
trade. This regulation is enforced effective from 2015 and in the year of 2020, the
sulphur content is supposed to be reduced to 0.1%. This will increase oil price which
will affect the ship building industry indirectly, since ship owners will not intend to buy
new ships considering the expenses spent on fuel.
Depending on its geological location, the adverse effects of the climatic hazards and
natural disasters are inevitable threats to the company. Tsunami disasters which took
place in 2004 is one such example.

14. 7
1.4. Profitability of the company
As far as financial statistics for the pas t 10 years are considered, Colombo Dockyard
has an average annual profit of 1090.3 million rupees and earns a total revenue of 12.6
billion rupees from ship repair, ship building, and offshore engineering services. Figure
1.2 shows an analysis of these statistics based on the information contained in the
annual report of 2015. Nevertheless, the company has shown a negative growth of
income during the past four years, the downfall of net profit starting from 2012. As per
the annual report of financial year ending on 31st
of December, 2015; the company
experienced a severe loss of 708 million rupees due to cancellation of a ship building
project. Despite these negative impacts, the company still operates at a strong
financially stable position.
-800
1200
3200
5200
7200
9200
11200
13200
15200
17200
2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Million Rupees
Year
Financial Statistics
Total revenue Net profit Total assets
Figure 1.2: Financial statistics for the past ten years

15. 8
2. Training Experience
One of the greatest satisfactions during the training period was to observe how classical
theories and principles of mechanical engineering were being used practically in the
industry. The nature of training at the training establishment as well as the experiences
and knowledge gained at each training location shall be explained henceforth in detail.
2.1. Nature of training at Colombo dockyard
More than 400 trainees from various technical institutions and Universities are being
trained annually at Colombo dockyard. The training schedules, training procedures and
all other affairs related to trainees are managed by the Training Centre of Colombo
Dockyard. All trainees are expected to practice good behavioral conduct, maintain
pleasant appearance (hair cut short, beard fully shaven) and strictly adhere to rules
imposed by the Training Centre.
Before the commencement of the training program, trainees are instructed regarding
safety precautions, and regulations to be adhered to. Afterwards, overalls and personal
protective equipment (safety belt, safety shoes, and hard helmet) are provided.
After going through this orientation program, I was assigned to several workshops and
departments to undergo training as stated in table 2.1. It was essential to submit a report
for each workshop/ department including the technical knowledge gained at each
training location.
Table 2.1: Training locations and time allocation.
Workshop/Department Main Category
Period of training
From To
Hull construction
department
Ship building 2016.08.01 2016.08.18
Safety department Administration 2016.08.19 2016.08.25
Plant shop Maintenance 2016.08.26 2016.09.18
Deck fitting shop Ship repair 2016.09.19 2016.10.09
Machinery outfitting Ship building 2016.10.10 2016.10.23
Engine fitting shop Production division 2016.10.24 2016.11.22
Machine shop Production division 2016.11.23 2016.12.15
Foundry Production division 2016.12.16 2016.12.20
Design department Design 2016.12.21 2016.12.31

16. 9
The variety of engineering scope at different worksites provided an invaluable opportunity to
broaden technical knowledge in many branches of engineering.
The table 2.2 includes only the areas in which practical experiences were gained and not
necessarily all the areas of specialization for each worksite. For an example, the Machinery-
Outfitting section is also specialized for propeller shaft alignment, bearing installations etc. and
the foundry is also specialized for rubber moulding. These areas could not be covered within
the limited time allotted.
Three projects were completed which were assigned by engineers at three different
workshops/departments namely Hull construction department, Engine fitting shop, and Design
department. The details of the projects carried out are explained in section 2.11.
Table 2.2: Areas of specialization of training worksites
Workshop/Department Areas of specialization
Hull construction department
Metal forming processes, CNC plate marking &
cutting, Welding, Lofting,
Safety department
Safety and risk management, Safety standards
(OHSAS 18001), Issuing of work permits
Plant shop Machinery & Gas line system maintenance
Deck-fitting shop
Overhaul and testing of deck-machinery &
Hydraulic valves, pressure-vacuum valves.
Machinery Outfitting Piping system installation & testing, Pipe welding
Engine-fitting shop
Overhaul & pressure testing of main engines,
pumps, heat exchangers.
Machine shop
Machining operations: Lathe machine, Milling
machine, Boring machine, radial arm drill
& Dynamic balancing of rotors.
Foundry Sand casting and die casting methods.
Design department Design process, Load-line surveying.

17. 10
The names of key training personnel of each training location along with their designations are
listed in the table 2.3.
Whenever assigned to a new training location, a brief introduction about the functions of
workshop or department, important areas of specialization, and role of workshop engineer were
explained by the training personnel. The report about technical knowledge gained from the
training location was checked and questions were asked from the contents of the report as well
as from background knowledge.
Table 2.3: Details of key training personnel
Workshop/Department Name of training personnel Designation
Hull construction
department
R.K.A.G. Rathnayaka Engineer
Safety department R.M.P. Ratnayake Head of section
Plant shop W.L.N. Fernando Maintenance Engineer
Deck-fitting shop B.M.C.S.H. Bandara Engineer
Machinery Outfitting P.S.M.G.R. Watovita Engineer
Engine-fitting shop D.G.C.A. Rambukwella Engineer
Machine shop J.C.W. Edirisooriya Engineer
Foundry K.C. Wickramatunge Senior Engineer
Design department T.H.K. Peiris Designs Engineer

18. 11
2.2. Hull construction department
This department is one of the main departments belonging to ship building section of
Colombo dockyard. It bears the sole responsibility of producing the hull of a newly built
ship starting from steel plates as raw materials. This enabled myself to get a sound
understanding as to how the operations of a large scale production process was managed.
At that time, the company was working on three ship building projects namely NC-234
(Multi-purpose vessel), NC-235 (anchor handling vessel), & NC-236 with similar naval
architecture. Project NC-234 was at the commissioning stage, NC-235 at the machinery
installation and testing stage, and NC-236 was at the preliminary construction stage. This
provided an opportunity to observe how a ship is built from the preliminary stage up to
final stage of the process.
Initially, the ships NC-234 and NC-235 were visited often to get familiarized with the
structure of a marine vessel. Cement tanks of the vessel NC-235 were being tested at that
time. Various tank testing methods are used to detect manufacturing errors such as welding
defects. Some of the tank testing methods being used at Colombo Dockyard are mentioned
below.
 Air-leak test:- Pressurized air is sent into the tank and the pressure is raised to
0.2bar. A soapy liquid is sprayed along the welding seams and leaks are detected
by the emission of air bubbles from the defective area.
 Hydro-pneumatic test:- Both pressurized water as well as air is sent into the tank
to test structural integrity.
 Non-destructive testing:- These tests are carried out by the quality control
department to detect manufacturing defects more accurately. X-ray/Gamma ray
test, dye penetrant method and magnetic particle testing are the techniques
currently being used.
During the period spent at the hull construction, additional training was provided at three
worksites belonging to the department. They were,
 Loft
 Steel workshop
 Hull unit-assembly section (Dry dock No.2)

19. 12
2.2.1. Loft
A template or a mockup is required for metal forming processes such as bending, and
rolling. Those templates resemble the exact details of curvature of the final product.
Loft is the workshop in which these templates and mockups are prepared. Hull-marking
is another duty fulfilled by the Loft.
 Preparation of templates:- The initial step is to generate the curve on an asbestos
sheet. Vertical distances to several points on the curve are calculated with reference to
a base line. This is done using a computer program based on the 3D model of the curved
plate. In other words, this is merely an interpolation method to draw a complex curve
as shown in figure 2.1. Once the points are marked, the curve is drawn and the template
is sawed off from the asbestos sheet.
Figure 2.1: Marking the curvature of a template used in metal forming
 Hull-marking:- Ship name, IMO (International Maritime Organization) number,
Draft mark, Bulkhead marks, Bow mark, Thruster mark and Skeg mark are the typical
hull markings made on a ship. The locations, and sizes of these marking are determined
by the Loft.

20. 13
2.2.2. Steel workshop
Most of the metal forming processes required for hull construction are completed at the steel
workshop. Material ordering, plate marking and cutting, metal forming, and metal fabrication
are the functions performed by the steel workshop. Simply, the duty of steel workshop is to
manufacture structural components required for various sections of a hull (such as the outer
shell, stiffeners, bulkheads, and frames) starting from steel plates as raw materials.
The flow chart in figure 2.2 will provide a basic understanding about the function of steel
workshop.
Figure 2. 2: Functions of steel workshop
Material
ordering
• Selection of ,
• Suitable material (Steel grade)
• Plate thickness
• Surface finishing (blasting, galvanizing or none)
Plate marking
& Cutting
• Obtaining nesting files for CNC plasma cutting machine
• Performing plate marking, cutting and removal operations
• Delivery of itmes to relevant sections after metal cutting
Metal
forming
• Ordering required templates and mockups from the Loft
• Forming the plate into required shape as per production
drawings using follwing methods.
• Bending
• Rolling
• Line heating
Fabrication
• Bevelling using pug cutter
• Welding and fabrication of required components
• Grinding and finishing

21. 14
The training gained from this worksite is
even more important due to availability
of heavy machinery for metal forming
processes. The operation a CNC machine
was clearly observed that is shown in
figure 2.3.The most important component
of the plasma cutting machine is the
plasma torch. A cross-section model of a
real plasma torch was available at the
plant shop so that its fine details could be
observed.
Bending of steel plates were done using two hydraulic press machines with pressing force
capacities of 300T and 500T. Two rolling machines were available to obtain large curvatures
one of which is shown in figure 2.5. Operating methods of machines, bending procedure of a
metal plate, usage of wooden templates and specific work holding methods used were noted.
Figure 2. 5: Plate rolling machine
Figure 2. 3: CNC Plasma plate cutting machine
Figure 2. 4: Hydraulic press machine

22. 15
2.2.3. Line heating process
Line heating is a technique of metal forming that is widely being used in hull-making
but uncommon in most of the other industries. This is a practical application of
deformation due to thermal stresses. Line heating is employed to bend plates into
complex shapes of curvature (ex: - Saddle shape) that cannot be achieved using
hydraulic press machine or rolling machine.
 Operating principle: -
When an object is subjected to heat, it tends to expand. Non-linear heat flow rate will
produce a temperature gradient along its cross section. This gives rise to thermal
stresses due to uneven expansion causing the object to deform similar to what happens
when physical forces are applied. Upon cooling, these stresses are relieved leaving a
certain amount of plastic deformation. Line heating is a successful method of utilizing
this deformation to bend metal plates into required shape.
 Requirements :- LP gas torch, Water line, Pyrometer, two skilled workers
One worker is required to perform heating and another to perform cooling
synchronously. It should be noted that both workers must have a good experience
in line heating method.
 Procedure :-
 Wooden templates for bending are ordered from Loft before performing any
job.
 Plate is divided into sections depending on the plate thickness indicated below
in table 2.4 and curvature required.
Table 2.4: Heat line spacing details
Plate thickness
(inches)
Heat line spacing
(mm)
4 100
6 150
8 200
10 250

23. 16
 Lines are then drawn on the plate surface using a piece of chalk. This is done intuitively
by worker’s experience and not specified on production drawings.
 Flame of the gas torch is adjusted until the bluish flame recommended for line heating
is obtained.
 Plate is then heated by running the flame along the lines drawn previously and heated
area is simultaneously cooled by a water jet controlled by another worker.
 Temperature of the plate is measured using a pyrometer while heating to ensure that it
is below 650°C. If this temperature is exceeded, gas flow is reduced.
 After one series of heating, the curvature of the plate is compared with wooden
templates. Several series of heating are repeated as described above until the required
curvature is obtained.
It is essential to maintain the surface temperature below 650°C so that microstructure of the
plate material is not affected. This range of temperature is chosen because the phase change of
α-ferrite + Cementite (Fe3C) phase occurs at temperatures above 727°C. Unlike other forming
processes, the quality of the final product in line heating greatly depends on the skill of the
worker. Figure 2.6 shows a plate formed using line heating method.
Figure 2. 6: Plates formed by line heating

24. 17
2.3. Safety department
Marine sector is ranked on top amongst the most dangerous fields of occupation in the
world. Safety is therefore a primary concern at Colombo Dockyard as a company that
has been awarded the safety standard ‘OHSAS 18001’.
Administering of safety and risk is the major duty of Safety department. Issuing of work
permits for man-entry, hot-work & radioactivity, checking noise-levels and quality of
air at worksites, patrolling risky worksites such as dry docks to inspect safety issues are
typical functions performed by the Safety department. The practical as well as
theoretical exposure gained during one week period of training at the Safety department
is explained below.
Safety and risk management can be fulfilled in three aspects which are namely,
 Administrational control
 Engineering control
 Self-discipline
2.3.1. Administrational control
Ensuring safety within a work environment by enforcing laws, enacting appropriate
restrictions and by continuously monitoring is known as administrational control.
Issuing of permits for various purposes is one method of administrational control to
ensure safety. A permit is valid only for a specified time period. Even during the validity
period, permit-related activities are regularly monitored by the Safety department. Some
of the permits are described below.
 Man-entry permit:-
A man-entry permit must be obtained before entering into a confined space for any
sort of activity. (Ex: - Ballast tanks, cargo tanks etc. found in marine vessels).This
restriction avoids unauthorized entrance into dangerous workspaces thereby
reducing the possibility of hazardous situations. Following factors are considered
by safety officers before issuing a man-entry permit.
o Availability of clear paths for entrance and exit (Approved ladders, scaffoldings
etc.)
o Presence of sufficient ventilation and proper lighting conditions
o Presence of moving parts such as chain drives, shafts which may cause damage
to a worker (All moving parts must be isolated, if any).

25. 18
o Quality of air within the confined space (Percentages of Nitrogen, Oxygen &
Carbon dioxide and absence of toxic gases)
o Duration of time required to carry out work within the confined space
o Evacuation facility in case of an emergency
 Hot-work permit:-
It is essential to acquire a hot work permit before carrying out thermal activities such as
welding, gas cutting, and line heating etc. in restricted areas. Presence of even a slight
amount of inflammable substance is sufficient to cause a spark when it is sufficiently
heated. Therefore, all thermal activities are considered risky and following requirements
must be fulfilled in obtaining a hot-work permit.
 Man-entry permit must be acquired for the relevant worksite
 Work area should not contain inflammable substances beyond specified limits.
(LEL<10%, CO < 35 ppm, H2S< 35 ppm, O2=20.9%)
 Boundary of hot work must be suitably enclosed to avoid penetration of heat into
unwanted areas. (because openings such as ducts, air vents, louvers etc. may
propagate heat to another area and cause a hazardous fire)
 Workers must be qualified to perform hot work and proper equipment must be used.
 Firefighting facilities must be readily available and a fireman should be present near
the worksite at all working hours.
Even if above conditions are satisfied, hot-work activities are closely monitored because
work environment (especially onboard ships under construction or repair) changes
unpredictably. Confined spaces are daily checked in the morning before starting any work.
A gas meter is used to check the percentages of gases present within the workspace.
Practical experience was gained in using a gas meter during those daily patrols.
 Radioactivity permit:-
Harmful electromagnetic rays such as X-rays, and Gamma rays are used by the quality
control department of Colombo Dockyard to detect manufacturing defects in ship building
projects.
 Usage of radioactive substances should be such that effective dose received by an
individual may not exceed 1 mSv/year
 An area within 20m of radioactive zone must be evacuated.
 All workers must be informed via early announcements to communicate the
location as well as duration through which radioactive work is carried out.

26. 19
2.3.2. Engineering control
Ensuring safety using engineering or technical measures such as guard rails, firefighting
systems, safety alarms, sensors, and PPE (Part Protective Equipment) etc. is known as
‘Engineering control’ method of safety management. Some of the engineering control aspects
adopted at Colombo Dockyard are briefly stated below.
 PPEs are provided for every employee and special protective equipment are provided
to perform specific tasks such as welding, grinding, foundry work etc.
 A safety alarm is signaled whenever a hoist crane is on the move along its guide rails.
Trained riggers were available to communicate with the crane operator during any sort
of hoisting activity.
 The gas line system in the yard is protected with flash back arrestors installed at gas
supply ports to avoid propagation of fire. Function of flash back arrestor is explained
in section 2.4.2.
 Fire department is well-equipped with standard fire extinguishers and resourceful with
trained firemen.
 A 4-colour code is followed for risky equipment such as gas-cutting torch, welding
torch, chain blocks etc. to ensure that they are tested and repaired every three months.
 Noise levels, amount of dust, and quality of air is measured frequently in dry docks
using measuring equipment such as gas meters, dust meters etc.
 Scaffoldings required for worksites (mostly dry docks used for ship building projects)
are laid by the service department according to standards. Scaffoldings must also be
approved by the Safety department.
 A colour code is followed to identify separate gas supply lines. (Oxygen-blue,
Acetylene-red, CO2 – black, Argon- grey & Nitrogen- green)
The above aspects were described based only on personal observations made during the entire
training period.

27. 20
2.4. Plant shop
2.4.1. Introduction to Plant shop
Plant shop is the workshop responsible for maintenance of machinery, equipment, gas
line system etc. There are four aspects of maintenance which are followed by the plant
shop to provide its services effectively to the company.
 Predictive maintenance
This approach of maintenance is to forecast the condition of a machine by
continuously monitoring its performance and predict any possibility of failure in the
future. E.g.:- Monitoring the flow rate of a centrifugal pump in bilge water system
 Preventive maintenance
Preventive maintenance is the process of repairing or replacing certain parts of a
machine while it is still in the working conditions. This is done to prevent a possible
failure in the future. E.g.:- Replacing bearings of a pump
 Corrective maintenance
Repairing a machine after a breakdown has taken place is known as corrective
maintenance. This approach of maintenance is important to provide solutions to
unpredictable failure of machinery. E.g.:- Repairing vertical lathe machine of the
machine shop after its breakdown
 Scheduled maintenance
Scheduled maintenance is the process of performing pre-determined maintenance
schedules in due time. These schedules are carried out as per manufacturer’s
instructions or by considering the inspection reports of the workshop.
E.g.:- Re-installing flash back arrestors in the gas line system.
A great deal of hands-on experiences was obtained by engaging in various workshop
activities. Very often than not, machinery and equipment were dismantled to identify
their defects. This gave an insight on various machinery components and improved the
practical skill of understanding their functions. The workshop area is sub-divided into
sections depending on the type of function performed as listed below.
 Chain hoists repair section
 Generators and Compressors repair section
 Hydraulic machinery repair section
 Airless spray painting machine repair section
 Gas line system maintenance section

28. 21
 Electric equipment repair section (Grinders, hand drills etc.)
 Welding/ gas-cutting torch repair section
 Air conditioners repair section
2.4.2. Gas line system maintenance
The gas line system of Colombo Dockyard delivers gases to worksites that serve various
purposes. The main types of gases delivered are Oxygen, Acetylene, Carbon dioxide, Nitrogen,
Compressed air, and Argon. The gas line system consists of pipe line system, 3 large pressure
vessels, a central acetylene gas storage, pressure regulators, flash back arrestors and gas
manifolds etc. The duty of the plant shop is to carry out maintenance of those components.
Practical experiences were gained in fulfilling duties mentioned below.
 Testing & repairing pressure regulators
 Repairing flash back arrestors
 Replacement of pipe lines
 Regular inspection of gas lines in dry docks
 Inspection of central gas storage
2.4.2.1. Repairing method of a flash back arrestor
Flash back may occur when using welding torches as where mixing of fuel with oxygen
takes place. If the torch is pressurized beyond the recommended value for the torch tip
size, a back fire occurs. Flash back arrestor is a device installed in a gas line system to
prevent the propagation of fire along pipes towards gas storage tanks. Separate arrestors
are used for different gas lines.
The basic operating principle of a flash back arrestor is to remove heat from the flame as
it passes through narrow gaps of ceramic filter. Ceramic filter may get damaged due to
heat absorbed but the flame gets extinguished. Once a flash back has occurred, the arrestor
must be repaired as follows for it to be re-used.
o The flash back arrestor is fully dismantled by removing the head nut and its
assembly.
o The net, head nut, mopler and the screw nut are brushed to remove unburnt Carbon
residues and cleaned with teepol.
o Washer, and the Teflon cone are replaced with new parts and if the ceramic filters
are also damaged, the arrestor is discarded.
o The flash back arrestor is then assembled in the order shown in figure 2.7.

29. 22
The figure 2.7 indicates basic components of an acetylene flash back arrestor that was
dismantled in the workshop for repair work. The diagram is not drawn to scale.
In the above figure 2.7, the direction of gas flow is from right to left. Due to the pressure of the
flowing gas, the spring is compressed and the valve is pushed open. In the reverse flow the
valve is normally closed.
2.4.2.2. Inspection of central gas storage
The central storage of acetylene that supplies acetylene to dry docks comprises of 160
acetylene tanks (with a capacity of 7.6 liters each). Storage is divided into two sections
comprising of 80 acetylene tanks each. One section is connected to the supply line of
acetylene and other one is used as a standby supply.
During the inspection routine, outlet pressure reading from the main pressure regulator
was checked. If that pressure reading is far below the standard delivery pressure of 1.5
bar, the standby section is connected to the supply line and the used section is replaced
with new acetylene tanks.
The next task was the inspection of huge pressure vessels that are used to store Oxygen
and Carbon dioxide. There are two storage tanks for Oxygen with capacities of 10,000
liters and 32,000 liters and one storage tank with a capacity of 17,500 liters for Carbon
dioxide. Pressure readings from the pressure regulators at outlets and temperature
readings indicating the internal temperatures of storage tanks were inspected on daily-
basis. Outlet pressure for Oxygen was maintained between 7.5 bar to 8 bar and that of
Carbon dioxide was maintained at 5 bar.
Figure 2.7: Basic components of a flash back arrestor

30. 23
It is essential to maintain the internal temperatures of storage tanks at -190 °C and
pressure at 24 bar to retain these gases in the liquid state.
2.4.3. Maintenance of airless spray painting machine
Airless spray painting machines are widely used at Colombo Dockyard for hull
treatment due to its ability of painting a large surface area within a short period of time.
Compressed air is not used in this sprayer to cause atomization of paint fluid thus giving
its name ‘airless spray painting machine’.
Apart from knowing its maintenance procedure, a valuable knowledge was given at the
plant shop regarding the operating principle of this machine. Airless spraying machine
is patented due its unique design of the piston-type fluid pump. The pump displaces
fluid in both upward and downward strokes providing a uniform flow rate. Tip orifice
size and the pressure determines the fluid flow rate. During the upward stroke, the upper
ball (near the outlet) is closed while the lower ball gets opened and fluid is displaced
through side gaps. In the downward stroke, lower ball gets closed and trapped amount
of fluid pushes upper ball open. Hence, fluid is displaced in both strokes. (Refer to
annex 3 to get a better understanding about its mechanism)
Airless spray painting machines malfunction and require maintenance due to several
reasons mentioned below.
 Worn out pump components such as displacement rod, sleeve, throat and piston
packing, balls and seats etc.
 Spray tip getting worn out causing leakage of paint
 Blockage of filters (gun filter, tip filter and manifold filter) due to solidification
of paint material
 Defects in hoses including abrasions, holes, blisters etc.
Worn out components are replaced as per the instructions in the service manual. Hose
connections, suction lines are properly cleaned and then assembled.

31. 24
2.5. Deck-fitting shop
2.5.1. Functions of Deck-fitting shop
Deck fitting shop is responsible for carrying out repair work on deck-machinery such
as winches, deck cranes, derricks, hatches, and windlasses. Overhauling and testing of
a wide range of valves are also done by the deck-fitting shop. A broad knowledge on
machinery components, and their assembling methods was gained by working with
employees of the deck-fitting shop. Practical experiences were gained by involving in
dismantling and assembling of deck-machinery that were carried out in ships docked
for repair. ‘CLEMENTINA F’, ‘ASPAM 1’ and ‘DCI DREDGE XIV’ are the ships in
which hands-on experiences were gained during three-week training period spent at the
deck-fitting shop. Many types of valves including globe valves, butterfly valves, ball
valves, gate valves and pressure vacuum valves were practically observed during the
dismantling process.
2.5.2. Repairing procedure for an anchor mooring winch
An anchor mooring winch is a type of deck-machinery used to lower or lift a ship
anchor. Two mooring winches of a marine tanker vessel named “CLEMENTINA F”
were repaired during the training period. Hands on-experiences were acquired and the
complete procedure is explained below. The two anchors and chain drives were already
removed from the winch at the commencement of repair work.
Dismantling winch components
 Initially, the wire connections of the electric motor were disconnected from the
main power line by an electrician.
 Gearbox was disconnected from the drive shaft coupling and was sent to the
workshop for further dismantling.
 Brake was disengaged by rotating the screw handle and the brake liner was removed
from the winch.
Replacement or repair of damaged parts
The gearbox was fully dismantled in the workshop, and the oil bath was drained. Helical
gears were cleaned to remove rust. Brake liners were repaired in full by replacing its
inner packing and fastening it with bolts.

32. 25
2.5.3. Operation & testing of a Pressure-Vacuum valve
Pressure-Vacuum valves (abbreviated as PV-Valve) are often found in tankers (which
are huge ships carrying crude oil, LPG, LNG or chemicals). It is a specially designed
valve to maintain the internal pressure of a tank or a pressure vessel at a favourable
range. The PV-valve consists of two parts namely, pressure side and vacuum side.
When pressure within the tank increases due to emission or vaporization of gases, pallet
of the pressure valve is lifted upwards due to internal pressure, thereby releasing gases
and reducing pressure. Conversely when pressure inside the tank decreases to a very
low value, pallet of the vacuum valve gets pushed down due to atmospheric pressure
and prevents possible structural damage to the tank. In PV- valves brought to deck-
fitting shop, the pressure side operated at pressures above 0.2 bar and the vacuum side
operated at pressures below 0.035 bar.
When repairing a PV-valve, valve seats, pallets and diaphragm are either repaired or
replaced. The valve seats are either lapped or machined to ensure perfect contact
between the valve pallet and the valve seat. Rubbing the surface of the valve seat with
an abrasive material is known as lapping. A lapping paste containing boron carbide is
used at the workshop. Parts of the valve subjected to corrosion are cleaned by
immersing in a chemical bath. The procedure of chemical bath cleaning is explained in
section 2.7.3.
Compressed air is used in pressure testing of PV-valves and a manometer (height should
be more than 2 m) is used to take pressure readings. Pressure relief valve is pressurized
to a pressure of 2000 mmH2O and vacuum valve is pressurized to 350 mmH2O. The
pressure- valve and the vacuum valve are pressurized separately. Air is sent through the
valve at a standard flow rate specified by surveyors or stated in manufacturer’s manual.
Pressure is gradually increased by increasing the flow rate up to specified value. The
point at which pressure does not increase with corresponding increase in flow rate is
recorded. This is the test pressure for pressure-valve. The vacuum valve is also tested
by gradually reducing pressure and value is recorded in the same manner. Usually three
sets of records are obtained and if all of them lie within a tolerance limit of ±10% of
standard values (0.2 bar and 0.035 bar), the PV-valve is certified by the ship surveyor.
At instances where PV-valve fails the pressure test, weights of its pallets are altered by
adding masses and tested again.

33. 26
2.6. Machinery outfitting
2.6.1. Exposure gained at the workshop
Machinery outfitting (abbreviated as MOF) is a workshop that plays a major role in
ship building projects. All machinery installations, piping system installation, metallic
pipe manufacturing, propeller shaft alignments, bearing installations are all done by the
machinery outfitting workshop. Engineers of the MOF fulfill their duties in sea trials
and commissioning of marine vessels as well. During two-week period of training spent
at the MOF, various duties related to piping systems of two on-going ship building
projects named NC-234 and NC-235 were assigned on myself.
Piping system of a marine vessels comprises of bilge system, ballast system, sewage
system, firefighting lines, venting systems, engine cooling system and cargo fuel lines
etc. Therefore, entirety of the piping system of a marine vessel contains numerous
features; valves, pressure vessels, flanges, pipe fittings, pressure regulators, filters,
hydraulic pumps, accumulators etc. The practical knowledge gained while working
onboard ships (NC-234 & NC-235) was of immense use to understand how piping
systems are designed, and possible failure modes. Hands-on experiences were gained
in performing duties mentioned below.
 Testing the flow rate of a centrifugal pump in ballast system using a control
software.
 Testing the flow rate of a cooling pump belonging to ballast system using
ultrasonic flow rate tester.
 Installation of pressure gauges on suction and discharge lines of a centrifugal
pump.
 Inspection of piping layout of air venting system (Main deck level of project
NC-235)
 Inspection of piping layout of the water ballast system (Tween deck level of
project NC-235)
Apart from above experiences, knowledge on pipe welding, pipe bending and
mechanical pipe connections was also gathered from welders of the workshop. Welding
processes such as GMAW (Gas Metallic Arc Welding) and SMAW (Shielded Metallic
Arc Welding) were used at the MOF. Information about these welding processes such
as types of base materials, fluxes and electrodes used, welding positions etc. were
obtained from welders.

34. 27
2.6.2. Flow rate testing of the ballast system.
The ballast system of a marine vessel is used to hold brine or fresh water that is utilized
to maintain its stability. Ballast system comprises of ballast tanks to store water and
centrifugal pumps which transfer water in or out of the vessel, thereby controlling the
weight and adjusting location of the center of gravity.
During the training period at MOF, it was required to test flow rates through centrifugal
pumps of the ballast system in NC-234. This was done to confirm whether the flow rate
was adequate according to the standards required by ship surveyors. Monitoring of the
bilge system was done with the aid of ‘K-Chief 600’ ballast automation system.
Procedure that was followed is explained below in detail.
 Initially all valves of the bilge system were closed manually and using ‘K-Chief
600’ ballast automation system, valves and pumps were controlled throughout the
testing procedure.
 The initial volumes of ballast water available in each ballast tank were noted using
the above control system.
 Supply valve of tank No.1 on starboard side (right side when facing the front of the
vessel) and the discharge valve of tank no.1 on port side (left side when facing the
front of the vessel) were fully opened.
 Then the centrifugal pump was switched on allowing ballast water from port side
tank No.1 to be pumped into the starboard side tank No.1
 Amount of liquid transferred was observed for a duration of 5 minutes, and
corresponding flow rate was calculated in m3
/hr
 The same procedure was repeated for other ballast tanks to determine flow rates in
each case.
 Entire flow rate testing procedure was again carried out for the reverse order of fluid
flow.
Results of this testing procedure were tabulated and handed over to the quality control
department for further analysis. If the flow rates were not satisfactory, pipe orifice sizes
had to be altered in order to increase the flow rate.

35. 28
2.6.3. Ultrasonic flow rate testing method
Ultrasonic flow rate testing instrument was used while working onboard the ship NC-
234 to measure the flow rate of a cooling water pump. The working principle of an
ultrasonic flow rate tester is based on Doppler’s effect. The change in frequency of a
wave that occurs as a result of relative motion between the observer and the source
emitting the waves is known as Doppler’s effect. In ultrasonic flow rate tester, an
emitter sends out ultrasound waves inclined at an angle to the direction of fluid flow.
Reflected sound wave is received by a sensor and the difference in frequencies of
emitted and received waves are used to determine the flow rate. In order to calculate
the flow rate, following data were fed into the instrument.
 Outer diameter of the pipe
 Pipe thickness
2.6.4. Pipe fabrication
A basic knowledge on manufacturing engineering aspects related to pipe welding and
pipe bending was gained with the aid of fabricators at MOF. Generally, Gas Metal Arc
Welding (GMAW) is used for pipe fabrication at MOF. GMAW uses an externally
supplied shielding gas (either active or inert gas) to protect the molten weld pool. If an
active gas is used it is named as Metal Active Gas (MAG) welding and as Metal Inert
Gas (MIG) welding if an inert gas is used. However, these terms are not standard terms.
This welding process is specially chosen because it can be performed in all welding
positions. The welding positions commonly used at the workshop are 1G, 5G and 6G.
Some of the details related to GMAW process done at the workshop are mentioned
below. These details were extracted from a welding procedure specification (WPS)
obtained from the workshop.
 Type of electrode & Diameter:- 2% thoriated tungsten electrode
 Type of flux:- Low hydrogen
 Electrode baking temperature & duration:- 350 °C, 1 hour
 Shielding gas: - Argon, used at a flow rate of 7 l/min.

36. 29
2.7. Engine-fitting shop
2.7.1. Introduction to Engine-fitting shop
Engine-fitting shop is a workshop belonging to ship repair division fulfilling duties
related to overhauling of main engine, auxiliary engines, heat exchangers, storm valves
and machinery such as turbochargers, hydraulic pumps etc. It also performs duties
related to general engineering services. Engine-fitting shop is sub-divided into sections
depending on the functions performed as listed below. During the four-week period
spent at the workshop, a greater amount of hands-on experiences were gained in each
of the following sections.
 Storm valves section
 Pumps section
 Main engine section
 Injector room
 Turbo chargers section
 Heat exchangers section
Various components of a main engine, including cylinder heads, fuel injector pump,
and pistons were overhauled and their testing methods were clearly understood by
practically involving in the procedure. Through observation, various fitting methods
were noted; for an example how bearings are fitted into shafts using induction heating
method, and gudgeon pin fixing technique by using liquid nitrogen. Knowledge on
material properties was equally important as the knowledge on mechanical engineering
to fully understand these procedures. Some of the important tasks through which
experiences were gained are briefly mentioned below.
 Overhauling and pressure testing of shell and tube coolers
 Overhauling and pressure testing of two-stroke engine cylinder heads
 Repairing and assembling fuel injector pumps
 Replacing roller bearings of the gearbox of a heavy duty hoist crane
 Pressure testing of main engine pistons
 Dismantling and repairing pumps of various types including centrifugal pumps,
gear pumps and screw pumps.
 Assembling a controllable pitch propeller

37. 30
2.7.2. Pressure testing of main engine cylinder heads
Most of the marine engines are two stroke engines which have either ‘in-line’ or v-type
arrangements. During an overhaul of a main engine, its components such as cylinder
heads are subjected to pressure tests to ensure that they are free of cracks. The presence
of a crack in jacket water lines of a cylinder head may cause the main engine to seize
and cause hazardous situations. Jacket water lines are the void spaces in a cylinder head
that facilitate circulation of cooling water. Leakage of cooling water through the crack
will allow fuel oil to get mixed with water. Contamination of fuel oil with water will
affect its ignition temperature and cause the engine to seize. Therefore pressure testing
of cylinder heads is very critical. Following procedure of testing was followed at the
engine-fitting shop.
 Apparatus: - Pressure testing apparatus, C-clamps, rubber packing, compressed air
line, water line, stop watch.
 Procedure:-
1) Cylinder head was held above the ground level, at a height of about 4 feet using
a chain hoist.
2) Jacket water line outlets (except one outlet) were fully sealed using rubber
packing and C-clamps tightened firmly against rubber packing.
3) One end of a rubber hose was connected to the inlet of jacket water line and the
other end was fixed to the water outlet of pressure testing apparatus. Testing
apparatus comprised of a pressure gauge, hand-operated pump, and a water
basin.
4) Jacket water line was then filled with water through the outlet that was not
sealed in step 2. Afterwards, the cylinder head was pressurized slightly using
the pump to remove air bubbles trapped in void spaces.
5) When emission of air bubbles stopped, the remaining outlet was also sealed as
stated in step 2.
6) Cylinder head was then gradually pressurized up to a pressure of 5 bar using the
hand-operated pump. This pressure was maintained for about 10 minutes.
7) Inner surface of the cylinder head was then dried by using compressed air line
to remove moisture.
8) Then the inner surface of the cylinder head was thoroughly checked for presence
of leaked water. This step completed the testing procedure.

38. 31
2.7.3. Overhauling and pressure testing of heat exchangers
Heat exchangers are widely being used in a ship for various purposes in heating as well
as cooling applications. Lubrication oil cooling, fresh water generators, condensers,
steam generators etc. are some examples for such applications. Shell and tube type and
plate type heat exchangers are most commonly found types of heat exchangers. A shell
and tube cooler was overhauled and tested at the engine-fitting shop and the entire
procedure is explained in detail below.
Overhauling:-
 End caps of the cooler and zinc anodes fixed in the shell were removed and
tubes were moved out of the shell.
 Solidified calcium deposits in the tubes were drilled first and then washed away
using a stream of water.
 The cooler was then descaled in a chemical bath according to the procedure
explained below.
1) All valves of the bath including the drain valve were fully closed and
chemical bath was checked for leaks.
2) Mixing tank was filled with water up to 2/3rd
of its volume approximately
to considering the displacement of water when the condenser is fully
immersed.
3) The tank was heated to a temperature of 55 °C using an immersion heater.
4) After heating is completed, a measured dosage of Sulphamic acid (SAF –
acid) was added into the mixing tank (5% by volume of water).
5) The mixing pump was switched on and the solution was allowed to mix for
about 15 minutes.
6) Once the solution is well mixed, the shell and tube cooler was fully
immersed in the Sulphamic solution.
7) Ultrasound generating transducer was switched on and the cooler was
allowed to remain in the chemical bath for 2 to 3 hours.
8) Cooler was removed from the bath and cleaned using a stream of clean
water.
 After completing the above cleaning procedure, new zinc anodes were fixed
inside the shell of the cooler. Then the cooler was fully assembled.

39. 32
Pressure testing:-
 Once overhauling process is complete, tubes of the heat exchanger were subjected to a
pressure test. This particular heat exchanger was a lubrication oil cooler. Heated lube oil is
passed through enclosed tubes and that heat is absorbed by sea water flowing across the
shell. Therefore it is necessary to confirm that the cooler is leak proof and no mixing of
lube oil with sea water takes place. Pressure testing of the cooler was done as follows.
 Sea water inlet was connected to a rubber hose whose other end was fixed to the water
outlet of pressure testing apparatus. (Same apparatus mentioned in section 2.7.2.)
 Shell was filled completely with water through the sea water outlet.
 Air trapped inside the cooler was removed by slightly pressurizing the shell.
 Then the sea water outlet was fully sealed using rubber packing.
 The shell was pressurized to 5 bar using hand-operated pump and checked for any
leakage of water through the shell into tubes of the cooler.
The use of ultrasound waves in a chemical bath is a modern technique of cleaning. When the
ultrasound generating transducer is switched on, it creates pressure waves having frequencies
above 20 kHz within the chemical solution. The pressure waves cause liquid particles to acquire
kinetic energy and move rapidly making more collisions among themselves penetrating into
small void spaces of the immersed object. In this way, contaminants are removed quite
efficiently.
Special safety gloves, safety boots, goggles and overalls were worn by workers while operating
near the chemical bath. Metallic components made of materials such as zinc, and aluminium
are not immersed in the chemical bath due to possibility of chemical reactions taking place.

40. 33
2.8. Machine shop
The machine shop is responsible for carrying out all sorts of machining work required
by Colombo Dockyard for ship building, ship repair and general engineering services.
The three-week period of training at the machine shop provided a sound knowledge on
machining operations together with practical experiences. Center lathe, vertical lathe,
shaping machine, universal milling machine, surface grinder, radial arm drilling
machine, horizontal boring machine and dynamic balancing machine are the types of
machines available at the workshop. An opportunity was given to get hands-on
experience in operating these machines whenever it was possible.
2.8.1. Hands-on experiences in machining operations
Lathe machine, milling machine and the radial arm drill are the machines frequently
used to fabricate metallic components having various features. Threads, holes, grooves,
fillets, tapers, chamfers, and countersinks are such features generally seen.
Hands on experiences were gained by performing various tasks and by assisting
machinists in the workshop. Some of the jobs performed are mentioned below.
 Fabrication of a hose tail
 Fabrication of a hexagonal nut
 Machining a spur gear
 Making pipe flanges
 Boring globe valves
 Machining the taper of a drill bit
 Slot milling the circular plate of a pump housing
 Metal spraying a rotor shaft
 Machining V-threads of a stud
Engaging in machining activities and through observation, most of the important
techniques of machining such as thread cutting, taper turning, indexing methods of a
milling machine etc. were thoroughly understood. Three weeks of training at the
machine shop provided a valuable opportunity to familiarize with lathe machine and
milling machine operations. Types of cutting tools used and their materials, cutting
fluids used and their applications, and the limitations of machining were noted. Apart
from that, operation of a vertical lathe machine, and horizontal boring machine were
also observed.

41. 34
2.8.1.1. Fabrication of a hexagonal nut
 The starting work piece was a solid, circular shaft of mild steel. The shaft was
step-turned using the center lathe until its outer diameter reduced to 60 mm.
 Several circular discs each having a width of 22 mm were cut-off from the above
work piece using the power saw.
 Then one of those circular discs (Outer diameter=60 mm) was placed on the work
holding vise of a universal milling machine.
 The disc was divided into six equal segments using simple indexing method as
follows,
 No. of faces to be milled = 6
 Gear ratio of indexing plate = 40:1
 No. of rotations of indexing plate =
40
6
= 6
4
6
 The indexing circle with 18 holes was chosen as 18 is exactly divisible
by 6.
 No. of holes in
4
6
th
of rotation =
4
6
x 18 = 12 holes
To rotate the circular disc through 60°, the indexing plate handle was rotated
through 6 complete rotations and up to 12 holes of the relevant circle.
 A hexagonal solid was milled by using face milling cutter and the work piece
was rotated through 60° after every milling operation.
 The above hexagonal solid was placed on the center lathe held by a three-jaw
chuck.
 Facing operation was done on both hexagonal surfaces to obtain a width of 20
mm.
 Work piece was drilled at its center and boring operation was performed on the
center lathe machine to produce a hole having a diameter of 42 mm.
 From the specified TPI (Threads Per Inch) value of 11, the pitch of the V-thread
was calculated to be 2.3 mm. Relevant speed of spindle and feed rate were
adjusted, and the thread cutting operation was completed step-wise.

42. 35
2.8.1.2. Fabrication of a pipe flange
 The initial work piece was a solid mild steel disc with a diameter of 210 mm.
 Work piece was held in the center lathe using a three-jaw chuck and straight
turning was done in three steps to reduce its outer diameter to 205 mm.
 Face turning was done on two circular faces to obtain a face width of 25 mm.
 Work piece was removed from the lathe and a pitch circle having a diameter of
163 mm was drawn on the circular face. Pitch circle was divided into four parts
and the four points were marked using center punch.
 At its center, a circular portion of diameter 90 mm was cut using the gas-cutting
torch.
 The facing tool was replaced by a boring tool on the tool post and the disc was
bored starting from its inner diameter (90 mm) to create a bore of diameter 91
mm.
 Two face grooving operations were done at diameters 100 mm and 110 mm
each having a thickness of 2 mm.
 The machined work piece was removed from the lathe and placed on the bed of
radial arm drill and held tightly.
 Four holes each having a diameter of 12mm were drilled using the radial arm
drill. The pipe flange was complete after this operation.
Figure 2.8: Geometric details of pipe flange

43. 36
2.8.2. Dynamic balancing of a rotor
When the center of mass of a rotating object has an eccentricity from the axis of
rotation, it is said to have an unbalance both statically and dynamically. Static
unbalance occurs due to unbalanced moment of the weight of rotor about shaft axis.
Dynamic unbalance occurs as a result of the moment generated due to centrifugal force.
The dynamic unbalance moment is given by equation (2.1).
M0 = mw2
rL................................ (2.1)
Where, m = rotor mass, w = Rotation speed, r= eccentricity of center of mass, L=
horizontal distance from reference point
The main importance of dynamic balancing is to minimize vibrations that occur due to
reciprocating and rotational motions of machinery parts. Especially in a marine vessel,
where crankshaft of the main engine rotates at a speed more than 750 rpm along with a
high inertia, the slightest dynamic unbalance can cause vibrations having high
frequencies.
Balancing tolerance calculations
 Data :- Rotation speed of rotor = w (rpm)
Rotor mass = m (kg)
Working radius at left plane = r1 (mm)
Working radius at right plane = r2 (mm)
 Following calculation steps must be followed to determine the allowable unbalance
mass (in grams) at each correction plane.
 As the first step, balance quality grade, G of the rotor must be determined using
ISO quality grade chart by considering the rotor type (refer annex A).
 Then the maximum permissible unbalance, Uper (g.mm/kg) can be determined
from the graph of permissible unbalance vs. rotor speed (refer annex B).
 If total permissible unbalance for rotor = Utotal
Then, Utotal = Uper x m (g.mm)
 Permissible unbalance mass for each correction plane must be calculated as
follows.
Uleft = Uright =
𝑈 𝑡𝑜𝑡𝑎𝑙
2
(g.mm)

44. 37
Therefore permissible unbalance masses are given by,
 Uleft =
𝑈 𝑙𝑒𝑓𝑡
𝑟1
……………………..(2.2)
 Uright =
𝑈 𝑟𝑖𝑔ℎ𝑡
𝑟2
……………………..(2.3)
Procedure:
A calculation sheet including above calculations was received by the balancing machine
operator. The operator’s task was to check whether the dynamic unbalances at left and right
planes exceed the maximum permissible value and make corrections. The procedure as
practically observed during the dynamic balancing of an impeller shown in figure 2.10 is
explained below.
 The rotor was mounted on a rotor shaft and it was placed on top of two roller supports
 Lengths a, b, & c indicated in figure 2.10 were measured and noted down on the
calculation sheet.
 Rotor shaft was then coupled to the drive shaft of the dynamic balancing machine using
an intermediate shaft and universal coupling.
 The shaft arrangement was aligned by altering the heights of roller supports using
adjustment screws.
 Once the setup was complete, the safety guards were positioned over the supports and
clamped firmly.
Figure 2.9: Dynamically balancing an impeller of a blower

45. 38
 Dynamic balancing machine was switched on and from the control panel following
data were fed into the database of the machine.
1. Lengths a, b, & c.
2. Balancing configuration (Single rotor in the middle of two supports)
 The drive shaft was rotated at the specified rpm by starting the electric motor.
 The amount of unbalance for left and right planes at different angles of the rotor were
displayed on the digital screen of the balancing machine.
 If the value indicated on the screen exceeds the permissible values calculated from
equations (2.2) and (2.3), machine was stopped and corrections were made by attaching
small masses at the working radii (r1 & r2) of each plane.
 Electric motor was switched on and again the values indicated on the screen are checked
and corrections are made until the permissible unbalance is reached.
The procedure mentioned above is only one method of balancing rotors dynamically and there
are other configurations that can be used with the dynamic balancing machine. This bearing
machine is a hard-bearing type balancing machine that measures vibrations at the supports
caused by centrifugal effects using a sensor.

46. 39
2.9. Foundry
2.9.1. Introduction to Foundry
During one-week period of training undergone at foundry shop, an exposure was gained
related to sand casting and die casting processes. Foundry is also specialized in rubber
moulding, but any practical experience could not be gained due to unavailability of
rubber moulding jobs within that period. However, a sound knowledge was acquired
on various aspects of sand casting including types of sands used and their properties,
special tools and safety equipment used in sand casting, mould-making, core & pattern
making, as well as temperatures and fluxes used.
A furnace which is fuelled using LPG (Liquid Petroleum Gas) had been built
underneath the ground level of the workshop. This is an efficient way of minimizing
heat losses in the furnace. This furnace is capable of heating up to a temperature of
1500 °C.
Two casting jobs were completed during this one week –period.
 Casting a large bronze ring using sand casting method
 Making Zinc anodes using die casting method
2.9.2. Casting a bronze ring using sand casting method
The requirement was to cast a bronze ring in order to fabricate the seal of a propeller
shaft. The duty of fabricating the seal by doing the necessary finishing operations was
given to the machine shop. Geometric details of the casting are,
 Outer diameter = 300 mm
 Inner diameter = 200 mm
 Thickness = 50 mm
 Melting :- Metallic bronze pieces were melted in a crucible heated up to 900 °C in
the furnace. Molten bronze was obtained after two hours of heating and a flux was
added on top of the crucible containing molten metal. This is done in order to
remove impurities from bronze.
 Preparation of sand :- Sillica sand containing silica and bentonite was mixed with
water and shoveled thoroughly. Water was added until the required quality of
moisture was obtained.

47. 40
 Preparation of the mould :- The patterns used for this casting were fabricated by the
metal workshop. Two hollow cylindrical shapes, one with an outer diameter of 300
mm and another with an inner diameter of 200 mm were used as patterns with
tolerances ±1 mm. Drag box was completely stuffed with prepared sand and was
compressed several times. Then the cope box was placed on its top and patterns
were placed concentrically by considering the dimensions of the cope. Another
cylinder was placed in the middle to create the vent hole and a conical shape was
placed at a corner to create the sprue. The cope box was then filled with sand and
compressed. After these preparations, graphite power was applied on the inner
surfaces of the mould.
 Pouring :- The crucible was lifted from the furnace by using a pair of large tongs
handled by two men. Pair of tongs were held by an overhead chain hoist to support
the weight of the crucible. Crucible was tilted near the sprue and molten metal was
poured continuously until the mould was filled.
 Finishing :- The mould was allowed to cool for about 24 hours and then it was
broken to remove the casting. Soldified sprue and runner were removed using gas-
cutting torch and the casting was grinded to give a better surface finish.
Figure 2.10: Pouring molten metal into the mould

48. 41
2.10. Design department
The design department of Colombo Dockyard plays a vital role in decision making,
process planning, and designing. Design department is divided into sections to fulfill
tasks related to new construction projects, heavy engineering projects, consultancy for
ship repair projects, and yard development projects. The main responsibility assigned
on myself was related to new construction projects namely NC-235 and NC-236. The
functions performed by the design department related to new construction projects are
as follows;
 Estimation, bidding, selection of basic design and involve in design development
according to ship owner’s requirements. Then detailed designing is carried out.
 Material ordering and specification of machinery, equipment to be used in the
production process
 Preparation of production drawings and engineering drawings containing
information like installation instructions, and operation procedures.
 Documentation of certificates issued for outsourced machinery installed in the
ship, basic design documents etc.
 Carrying out tests and trials to meet requirements of ship surveyors and
classification societies. These tests are basically basin trials (conducted while
afloat) and sea trials (conducted while sailing). Inclining experiment, engine and
equipment test, bollard pull test are examples for basin trials.
The duties fulfilled by myself were mainly related to documentation of test
certificates for machinery installed in the ship. This opportunity was utilized to read
and understand those documents containing valuable information about various types
of marine equipment. Testing procedures for pumps, coolers, propulsion system of
the ship, firefighting system, thrusters, main engine accessories were included in
those documents along with tabulated test results.
In addition to above duties, a load-line survey was conducted on the vessel NC-235.
A load-line survey is done to determine whether the vertical heights of various types
of openings (such as air vents, exhausts etc.) and doors from respective deck levels
are acceptable compared to standards required by classification societies. A drawing
of the vessel with locations of openings marked and a list of openings were provided.
Our duty was to locate those openings and measure their vertical heights above the
deck-level.

49. 42
The survey was conducted at various deck levels namely, main deck, forecastle deck,
upper forecastle deck, accommodation deck, wheel house top, and the bridge deck
level. The skill of reading and understanding an engineering drawing of a marine
vessel was improved in this task. Results were tabulated and compared with the
standard values. Part of this tabulation is included below to give some understanding
about the survey.
Table 2.5: Results of Load-line survey
TYPE OF
DOORS
DOOR
No. DECK
STANDARD
SILL
HEIGHT
(mm)
SILL HEIGHT
(SURVEY)
(mm)
Water tight
(wt-d) 11 Main deck 400 405
Weather
tight (wet-d)
12 Main deck 420 380
13 Main deck 410 410
14 Main deck 640 620
15 Main deck 640 605
16 Forecastle deck 380 395
17 Forecastle deck 380 390
18 Forecastle deck 390 400
19 Upper forecastle deck 410 425
20 Upper forecastle deck 410 420
21 Upper forecastle deck 410 390
22 Upper forecastle deck 410 420
23 Accommodation deck 410 415
24 Accommodation deck 410 410
25 Bridge deck 540 530
26 Bridge deck 540 540
27 Bridge deck 520 580
28 Wheel house top 380 380
29 Wheel house top 380 365

50. 43
2.11. Projects undertaken
2.11.1. Safety helmet project
This project which is mainly concerned about the safety of workers in Colombo
Dockyard PLC, was completed as per the instructions of Mr. R.K.A.G. Rathnayaka, an
engineer of the Hull construction department. This project was completed with the
collaboration of my colleague Mr. M.A.G.A. Mudannayaka, a mechanical engineering
undergraduate at University of Moratuwa. The objective of this project was to identify
possible reasons for the increased number of injuries taking place in worksites and
suggest effective solutions to minimize them. Although PPEs (Part Protective
Equipment) are provided for every employee, it had been noted that some workers were
reluctant to use them during work. In order to find possible reasons for this issue, the
following methodology was adopted in this project.
The initial step was to categorize different worksites by considering the level of risks
in each location. For an instance, when a dry dock worksite and an indoor workshop
are compared, the dry dock certainly inherits a higher level of risk. As the next step, a
survey was carried out to find the number of employees who are not wearing the safety
helmet properly while at work. The survey was done for each location separately.
Afterwards, some of the workers in these worksites were interviewed in a friendly
manner (workers were not informed of anything about this project) questioning why
they were reluctant to wear a safety helmet while working. Most of the reasons were
revealed using this method. It appeared that the design of the safety helmet had an
impact on this issue as well. Workers performing specific tasks such as welding and
grinding were unable wear the safety helmet with the eye-protective shield.
Several models of existing safety helmets were proposed along with reasons to provide
a feasible solution. Safety helmets that are equipped with eye-protective shield specially
designed for welders were also suggested. With the aid of this proposal, one such
sample model was ordered by Mr. R.K.A.G. Rathnayaka and it was tested on welders.
Welders were instructed to work for several hours wearing the new helmet and a
feedback was taken including their views on the new model compared to the old one.
Including these feedbacks, data collected from workers and from the survey, a project
report was submitted. The timeline of this project expanded for two weeks. The results
of this project were later submitted to the Safety department. The full report of this
project is annexed to this report. (Please refer annex 4)

51. 44
2.11.2. Improvement of workshop lighting system
This project was focused on identifying the drawbacks in the prevailing lighting system
of the engine fitting workshop which has a floor area more than 2000 m2
and propose
suggestions for improvement. Project work was initiated at the request of Mr. D.G.C.A.
Rambukwella who is the engineer in charge of engine-fitting shop. This project was
completed in collaboration with one of my colleagues, Mr. Theekshana Madhuranga, a
marine engineering student from the Ocean University.
The prevailing lighting system comprised 32 halogen lamps each with a power
consumption of 400 W and 24 transparent sheets were laid on the roof to acquire day
light. As the initial step, light intensity levels were measured at different locations of
the workshop under different light conditions using a lux meter (a digital device that
indicates light intensity in lux units). All lights are switched off during the lunch hour,
and this time period was chosen to measure light intensity under daylight conditions.
Light intensities at the same locations were again measured with all halogen lamps
switched on. After tabulation and analysis of data collected, it was found that the
average light intensity of the workshop with halogen lamps was 250 lux. However, the
minimum light intensity required for a fitting shop is 300 lux (recommended value is
500 lux) and therefore it was decided that the prevailing lighting system surely required
improvement. Another motivation for this project was to minimize the higher cost of
power consumption. Only two switches were available for the whole lighting system,
which was identified as another drawback.
Following suggestions were made for the improvement of the lighting system.
 Replacement of halogen lamps with LED lights having a power consumption
of 200 W and an illumination of 24,000 lumens.
 Increasing the number of transparent roofing sheets and laying them adequately
to acquire the maximum use of sunlight.
 Altering the current switching system for lamps such that unnecessary lamps
can be switched off whenever they are not in use.
The above suggestions were not mere qualitative recommendations but they were
supported with quantitative analysis supported with theoretical calculations. Having
considered these suggestions, a budget was also prepared for the implementation of this
project as per the request of Mr. D.G.C.A. Rambukwella.

52. 45
In order to prepare an estimate for the budget, following information were acquired from the
maintenance department of Colombo Dockyard PLC.
 Cost of an LED lamp fixture and cost of a halogen lamp
 Price of a transparent roofing sheet. (It was also mentioned by the maintenance officer
that transparent sheets were manufactured at Colombo Dockyard itself)
 Cost of unit power consumption (in Rs./kWh)
 Expenses of labour required for replacement of lamp fixtures and installation cost per
lamp.
 Life span of halogen lamps as per the general experience.
With the use of above information, the expenditure that has to be incurred on the proposed
improvements were calculated. Cost savings for a duration of 5 years was also calculated by
comparing with the power consumption of the prevailing lighting system. It was shown that a
saving of 1.3 million rupees could be gained by the replacement of halogen lamps and another
250,000 rupees by laying out transparent roofing sheets. Hence total savings by the
implementation of this project being over 1.5 million rupees. A project report including light
intensity data collected, suggestions for improvement, theoretical calculations and cost analysis
was submitted to Mr. D.G.C.A. Rambukwella. The full report has been annexed to this report.
(Please refer annex 5)
2.11.3. Ramp design project
The project NC-242 was the latest ship building project undertaken by Colombo Dockyard
PLC during the period of training. It is a deck-cargo ferry able to carry cargo weighing 2 tons,
40 persons and a crew of 4 people and able to move at a speed of 8 knots. The basic naval
architectural design of this vessel was done by the ‘Marine Consultants’ company in Kolkata.
This marine vessel was required to have a ramp that could be used to transport cargo when the
vessel is anchored at a pier. The ramp should be capable of supporting a weight of 300 kg.
However, the design of ramp done by the above mentioned company was not satisfactory
according to the view of Mr. Asitha Bandara, who is a project engineer of the design
department. According to his instructions, design project of ramp was commenced with the
collaboration of other 5 trainees of mechanical engineering stream. Project work had to be
carried out while engaging in activities of other workshops (assigned training locations) which
proved to be the real challenge.

53. 46
The major requirements of this project that needed to be fulfilled were as follows.
 Modify design of the ramp to provide a smooth landing.
 Suggest a suitable design for ramp hinges by determining hinge reactions and
performing strength calculations
 Design an efficient lifting & lowering mechanism.
 Select a suitable winch, winch ropes, pulleys etc.
 Design a ramp-holding method when the vessel is in motion and the ramp has been
lifted.
The ramp was initially decided to have only one degree of freedom, which is the rotational
motion about its hinge axis. Later it was decided that a small degree of movement should be
allowed parallel to hinge axis considering the ‘rolling’ of the vessel. (Oscillation of a floating
vessel about its longitudinal axis is known as ‘rolling’). Preliminary calculations were done to
determine hinge reactions and rope tensions for an arbitrary position of the ramp. After
determining the maximum rope tension, suitable specifications to select a winch were decided.
The winch chosen was hand driven, equipped with a ratchet mechanism and possessed a pulling
force capacity of 10kN. Ratchet mechanism is required to allow the ramp to be rested at any
angular position.
Lifting and lowering mechanism was designed with one pulley driven by the winch and another
set of pulleys attached to the ramp that are driven by a cable wound around the main pulley.
The required pulley sizes were determined by considering maximum rope tensions assuming
that the rope is properly lubricated. Dynamic friction was also taken into consideration in
design calculations. Ramp structure was modified by incorporating a flap at its landing end and
two castor wheels fitted with springs to absorb possible shock loads. Strength calculations were
done to select a suitable material and determine standard pipe sizes for supporting poles of the
ramp.
A calculation report was submitted to Mr. Asitha Bandara including the proposed modifications
for the ramp design. Completion of this project proved to be the essence of the training period
as theoretical knowledge gained from the university was put into practical use. A better
understanding was gained as to how engineers look into a design problem and the techniques
used by them to overcome problems which arise in the process. (Please refer annex 6)

54. 47
3. Conclusion
The industrial training period of 23 weeks was equivalent to a self-motivated practical
session where most of the theoretical knowledge acquired from the University was used
in practical applications. Due to the diversity of functions performed by workshops in
the training establishment, the exposure gained spread over a wide scope. Experiences
and knowledge acquired during the training comprised of engineering and technical
aspects as well as social aspects. The overall experience related to engineering can be
summarized as follows.
 Manufacturing engineering: - Welding, metal forming processes, CNC plasma
cutting, casting processes, machining, pipe fabrication.
 Fluid power and machinery: - Flow rate testing methods of pumps, maintenance
of centrifugal, diaphragm, gear-type and screw-type pumps, pipe system
installations, repair of valves.
 Production planning: - flow of a production process, material ordering, human
resource allocation, preparation of production drawings.
 Maintenance engineering:- Overhauling of marine engines, heat exchangers,
bearing installation.
 Quality control:- Non-destructive testing (Dye-penetrant, magnetic particle
testing)
Another benefit of undergoing industrial training was the familiarization with the
industrial environment, understanding the functions performed by persons at various
hierarchical levels of the organizational structure and their importance. The training
gained from the Safety department and Design department were of immense use in
achieving those aspects of industrial training. A sound knowledge on administrational
control and engineering control methods of risk management was gained from the
Safety department.
Apart from the technical knowledge and experiences gained, the social aspects learnt
from the training establishment will be of much use in my future career as an engineer.
Due to direct interaction with workers as a trainee, I was able to understand the issues
faced by them, their opinions about the company and the management, work attitude
and their work potential as well. Being among trainees from various technical
institutions was a novel experience and it was entirely different from the university
culture.

55. 48
Being able to represent IESL Mechanical Engineering sector at the techno exhibition, 2016 as
demonstrator was also a great opportunity received from the training establishment. Some of
the technical knowledge gained from Colombo Dockyard were not available at the university.
Some of the areas which were unavailable at the university are briefly listed below.
 Line heating method of metal forming, and lofting.
 Rolling machine and hydraulic press operation
 Scientific testing methods:- Ultrasonic flow rate testing, magnetic particle testing
 CNC plasma plate cutting, preparation of nesting files.
 Boring machine operation. (Horizontal and vertical)
 Blasting chamber process
 Bearing installation by induction heating method
 Chemical bath procedure for cleaning metallic components
The training gained from Colombo Dockyard was also capable of reflecting my weaknesses as
an undergraduate. It was understood that I lacked skills in CAD (Computer Aided Design)
software, which are widely used in the industry for modelling as well as in preparing production
drawings. This deficiency was rather reflected during the completion of the ramp design
project. As a consequence of this self-understanding, my plan in the final year is to practice
CAD software like ‘SolidWorks’ and simulation programs like ‘ANSYS’ and ‘MatLab’. This
will be much useful in fulfilling requirements of final year project as well as in my future career
as an engineer. It was also realized that in order to become a successful engineer, soft skills
were also required in the industry. Presentation skills, report writing, communication skills in
compromising, negotiation and ability to work in a team were such soft skills identified during
the training period. In order to improve presentation skills, my intention is to involve in all
presentations to be delivered in the final year. A systematic knowledge regarding report writing
was acquired in preparing this training report that could not be gained during previous
semesters.
The Industrial Training Division must be appreciated for carrying out the entire training
program in such a systematic way. The handbook was of immense use in gaining a thorough
understanding about the objectives of undergoing industrial training period.

56. 49
As a training establishment, Colombo Dockyard is capable of providing training in a wide
scope of engineering. Especially, having a separate training center and its own responsible
officers was very helpful during the training. Submission of reports for every training location
(workshops and departments) was essential and these reports were checked by training officers
and workshop engineers. This was a very productive approach of providing in my opinion.
However, we were able to suggest several adjustments in the training schedule provided by the
Colombo Dockyard to the training manager, Mr. K.K.M.H.W.S.P. Silva. That suggestion was
to allocate number of weeks spent at each workshop by considering the stream of the
undergraduate. The same training schedule was provided to trainees in various fields like
marine engineering, mechanical engineering, electrical engineering, and trainees from other
technical institutions as well. This creates difficulties for trainees to obtain the maximum use
of their training.

57. Annex 1
vi
Source: “Balance quality requirements of rigid rotors”, IRD Balancing

58. Annex 2
vii
Source: “Balance quality requirements of rigid rotors”, IRD Balancing

59. Annex 3
viii

60. Annex 3 (Continued)
ix
Sectional view of the piston pump of airless spray painting machine

61. Annex 4
x
Project on wearing safety
helmets
SUBMITTED BY:
M.A.G.A.Mudannayake
W.A.C.S.Muthukumarana
INSTRUCTED BY:
Mr. Gayanath Rathnayake

62. Annex 4 (Continued)
xi
1. INTRODUCTION
Safety precautions play a vital role in the industry where the working conditions and nature of
the surroundings change unpredictably. Therefore, priority should be given to ensure the safety
of workers on and off the field.
Wearing a safety helmet along with necessary accessories (welding shield, ear muffs, chin
guard etc.) reduces the possible damage to a greater extent during the occurrence of sudden
accidents or hazards. The typical safety helmet provides protection against fire, electrical
shocks, sudden impact due to slipping or falling, and prevents the penetration of sharp objects.
The objective of this study is to propose a feasible solution to the problem of workers not
wearing safety helmets properly by carrying out a quantitative and qualitative analysis.
2. PROBLEM DEFINITION
Despite the efforts taken by the management and relevant officers, a major issue faced by the
Colombo dockyard is the negligence of employees in wearing the safety helmet along with
other PPEs. Factors causing this problem and drawbacks in the safety helmet model currently
being used need to be identified clearly. This issue has been addressed in this study by actually
taking the views of workers as well.

63. Annex 4 (Continued)
xii
3. IMPORTANCE OF SAFETY HELMET
Why use a safety helmet?
Helmets are useful as safety gear to reduce injuries in an uncontrolled environment. It will
minimize the impact that might occur in an accident to a certain level. Also gives the full
protection from small pressing situations.
Features expected from a safety helmet
 Absorbs as much energy as possible from a high impact
 Hardness: Resistance to penetration
 Presence of a strong strap that holds it tightly on the head after a hard blow.
 Comfortability of wearing: light weight, unobtrusive etc.
 Balanced design for optimum stability
 Quick and easy fitting
 Helmet should be as smooth and round as possible on the outside to prevent snagging
in a crash
 Visibility must not be obstructed by any additional parts
 Should be durable, easily cleaned, and should not dent in normal use
 Helmet should be readily recyclable

64. Annex 4 (Continued)
xiii
4. COLLECTION OF DATA
The data related to wearing a safety helmet were collected at different locations as mentioned
in the below table. These locations were chosen carefully in order to include almost all varieties
of working environments currently operating within Colombo dockyard. All observations were
made from 8.30 a.m. to 10.30 a.m. (excluding tea interval) since it was observed that a greater
extent of work were carried out and workers were more involved in work during this period of
time.
Attention was mainly given to the fact whether a given employee wears the safety helmet
properly or not. Data collected are independent of the position held by a particular person and
thus refer to all types of employees (Engineers, Supervisors, Fireman, Painters, and Welders
etc.)
Location
No. of employees
Wearing helmet
Not wearing
the helmet
Not wearing chin
guard/Loosely
wearing
NC 235 (Day 1) 72 15 32
NC 235 (Day 2) 71 17 25
NC 234 26 2 8
DOCK 4- PIER 29 2 9
LOFT, WORKSHOP 3 18 5 10
DOCK 3-PIER 16 7 5
STEEL WORKSHOP 16 15 19
HULL ASSEMBLY 20 10 5
DOCK 1-PIER 13 8 14
UNIT FABRICATION 14 18 11
Table 4.1

65. Annex 4 (Continued)
xiv
5. ANALYSIS OF DATA
The table below indicates the percentage of employees wearing and not wearing the safety
helmet properly for a better comparison between data collected from different locations.
Location
Percentage
Wearing helmet
Not wearing the
helmet
Not wearing chin
guard/Loosely
wearing
NC 235 (Day 1) 60.50% 12.61% 26.89%
NC 235 (Day 2) 62.8% 15.0% 22.1%
NC 234 72.2% 5.6% 22.2%
DOCK 4-PIER 72.5% 5.0% 22.5%
LOFT, WORKSHOP 3 54.5% 15.2% 30.3%
DOCK 3-PIER 57.1% 25.0% 17.9%
STEEL WORKSHOP 32.0% 30.0% 38.0%
HULL ASSEMBLY 57.1% 28.6% 14.3%
DOCK 1-PIER 37.1% 22.9% 40.0%
UNIT FABRICATION
SECTION
32.6% 41.9% 25.6%
Table 5.1
Taking the characteristics of above locations into consideration, they can be categorized into
three groups by combining them as follows.
Location
No. of employees
Wearing helmet
Not wearing
the helmet
Not wearing chin
guard/Loosely wearing
WORKSHOPS 48 38 40
PIERS 58 17 28
ON-BOARD NC 234 &
NC 235 97 19 33

66. Annex 4 (Continued)
xv
Table 5.2
Location
No. of employees
Wearing helmet
Not wearing the
helmet
Not wearing chin
guard/Loosely wearing
WORKSHOPS 38.1% 30.2% 31.7%
PIERS 56.3% 16.5% 27.2%
ON-BOARD NC
234 & NC 235 65.1% 12.8% 22.1%
Table 5.3
5.1 ON-BOARD NC 234 & NC 235
This is the location that involves a higher degree of risk relative to other two types of
working environments that were categorized above. The major reasons for this are
mentioned below.
 Unpredictable changes taking place within the surrounding
 Higher population density: - Comparatively a large number of employees are engaged in
different jobs within a limited space
 Lack of knowledge about other activities taking place within the work space: - Although
workers representing various sections (ex: - Machinery outfitting, Electricians & welders
etc.) work together, they do not seem to possess a mutual understanding about the
nature of jobs and risks involved in other sections.
 Presence of obstructive objects on the deck: -In most cases, laying of power lines, gas
hoses, & ropes etc. is inevitable depending on the nature of the job assigned.
Nevertheless, their presence may cause slipping and falling over the deck floor causing
serious injuries.

67. Annex 4 (Continued)
xvi
5.2 PIERS
In this category of working environment, the pathways along docks have been considered
for analysis. These locations are as risky as any other place in the dockyard due to the
presence heavy machinery such as cranes that operate frequently. It was also noted that
forklifts were randomly operating along pathways and therefore special attention must
always be given when walking along pathways. Unfortunately, it could be seen that
workers did not wear the safety helmet properly while walking.
65.1%
12.8%
22.1%
ON-BOARD NC 234 & NC 235
Wearing helmet Not wearing the helmet Not wearing chin guard/Loosely wearing
56.3%
16.5%
27.2%
PIERS
Wearing helmet Not wearing the helmet Not wearing chin guard/Loosely wearing

68. Annex 4 (Continued)
xvii
5.3 WORKSHOPS
This category of working space includes the combination of data collected from Loft,
Workshop 3, Steel workshop, & Unit fabrication section. Workshops show a drastic change in
the percentage of workers not wearing the helmet properly which is almost 70%. This
prompted a closer investigation to find out factual reasons. For this purpose, randomly chosen
workers were inquired as to why they were so reluctant to wear the safety helmet within the
workshop.
The main reason pointed out by the workers was that they were confident to work even
without wearing a safety helmet because they were familiar with all processes carried out
within the workshop. Apparently, most workers seemed to be under the misconception that
they are safe within the workshop. But there can be other types of accidents that are
unforeseen and not yet experienced.
38.1%
30.2%
31.7%
WORKSHOPS
Wearing helmet Not wearing the helmet Not wearing chin guard/Loosely wearing

69. Annex 4 (Continued)
xviii
6. REASONS WHY WORKERS IGNORE WEARING HELMETS OR NOT WEARING IT PROPERLY
From the people we speak we got these reasons as their ignorance of wearing the helmet
properly.
Main
problem
Reasons for negligence/not wearing
the helmet properly
Solutions
Chin strap
Inconvenience caused in wearing the
chin strap
Provide a cushioned chin
strap with maximum possible
comfort
Trapping of sweat in between the strap
and the chin will lead to rashes
Instruct workers on hygiene
and healthy practices
A shaven face is severely affected by
the chin strap
Remove chin strap and
instead provide a head harness
to ensure proper contact
between helmet and head
Welding
&
Grinding
It is impossible to wear the welding
shield along with the safety helmet
Use a helmet that can be used
in both welding and grinding
operations. Several models
are suggested in this report
Wearing safety goggles for grinding
with the helmet on is difficult
Gas
cutting
It is difficult to wear gas cutting
goggle with the helmet
Provide a well-designed gas
cutting goggle
Long-
term
operations
Wearing the helmet for a long duration
is inconvenient
Introduce air vents on top of
the safety helmet without
affecting overall strength of
the helmet
So we can clearly see that the main problem of the ignorance is with the chin strap, except
in welding and grinding operations. Also in the investigation we figured out that majority
of the people are wearing the chin strap which is with the plastic lock instead of the ones

70. Annex 4 (Continued)
xix
with the plastic cup. But among those with the plastic lock, most of them are not wearing
it tight. Another important thing is that the welders are lazy to use the welding shield as a
grinding shield which leads to hazardous situations.
Figure 1.0
Figure 2.0

71. Annex 4 (Continued)
xx
Figure 4.0
 The chin strap which shown in Figure 1.0 is without the plastic cup or plastic lock. But the
design is simple and the comfort is there ahead of the above two types.
 The head harness shown in Figure 2.0 is designed to have the maximum comfort meanwhile
giving a good grip to the head.
 Figure 3.0 shows a conventional welder’s helmet and a modern welder’s helmet which is
modified to use while grinding by including a hard plastic lens and also a good head
protection
 Helmet on the Figure 4.0 is designed to use with the goggles and have the option of having
vents
6.2 Having a strong strap
A helmet must be stayed on the user’s head after the first crash to protect his/her head
against the typical second hit that might happen. That means it require a strong strap.
Otherwise the first incident will save you but not the second.
6.3 Adjustment and fit
To stay on your head in a bad crash the helmet has to be securely strapped on, not just
sitting on your head. It must be level on your head and not tilted back, or big chunks of
forehead can be left completely unprotected.

72. Annex 4 (Continued)
xxi
But it has to be convenient to adjust as much as you want and wear it for a long time. But in
some cases the chin strap used is not up to the better convenient level. So providing an upmost
place to the chin strap will leave the people to wear it decent period of time.
7. NEWLY PROPOSED SAFETY HELMET MODEL & FEEDBACK
Considering above detected problems with welders a new safety helmet design was introduced
and a sample was given to a welder to give a feedback about the new safety helmet model.
Several views of the proposed safety helmet model
Welding shield currently in use

73. Annex 4 (Continued)
xxii
The worker used it about one day and gave us the following feedback. The below table gives
advantages as well as disadvantages (things to be improved) in the proposed safety helmet
model compared to welding shield currently in use.
Advantages Disadvantages
Provides good overhead protection Ears are not sufficiently covered
Large safety glass provides a better
range of view
Helmet cannot be fitted tightly, poor
adjustment method. The tightening screw in
the old model is preferred.
Vents on the top of the helmet
gives comfort, and prevents
excessive heating
Hardness of the shield is comparatively
lower
Chin area is not covered sufficiently
As per the conversation with workers it was felt that improving the conventional one with an
overhead protection, relatively large lid so that grinding operations can also be done would be
a better solution. The new safety helmet can be modified up to the above standards and after
utilizing it for some time workers will get used to it.
8. GAS CUTTING GOGGLES

74. Annex 4 (Continued)
xxiii
Fig 1.0 (Recently exported model)
Currently used goggle type
Workers are happy with the current model over the above model due to the ease of use it with
the safety helmet. But there are some pros and cons of the cureent model.
Advantages Disadvantages
Ease of use with the safety helmet Corrosion resistance is very low
Simple design Life time is low
Lens cannot remove from the goggle
Dark lens is the only option unless it
need to remove for better viewing
As shown in the Fig 1.0 (right side) the corrosion resistance of the goggle is very low under
the dockyard conditions. Goggle shown in Fig 2.0 has more pros than the other model but it is
not capable of wearing with the safety helmet. Also it has the option of having two lenses for
better viewing. There are some models which can be utilized with the safety helmet on and no
problem with the corrosion neither with life time.

75. Annex 5
xxiv
PROPOSAL FOR A NEW LIGHTING SYSTEM
ENGINE FITTING SHOP
COLOMBO DOCKYARD PLC
Instructed by
Mr. D.G.C.A. Rambukwella

76. Annex 5 (Continued)
xxv
ABSTRACT
This study was carried out with the intention of identifying the drawbacks of the lighting system
currently being used in the workshop area occupied by both Engine fitting shop and part of the
machine shop. Several methods of improving the lighting system have been proposed in this
report with details of implementation.
1. Replacement of Halogen lamps with LED fixtures
Halogen lamps use a halogen gas such as Iodine or bromine along with a tungsten filament to
emit light. This can be operated at very high temperatures thereby emitting light with high
intensity and much brighter than conventional incandescent bulbs. The lamps that have been
installed in the workshop are halogen lamps with a power consumption of 400W per lamp. By
considering the energy cost expended on the lighting system, it is advisable to use LED lamps
with equivalent capacity of illumination. A brief qualitative analysis is presented below by
comparing the performances of Halogen and LED lamps.
Table 1.1 Comparison between Halogen lamp and LED
Halogen Lamp LED Lamp
Consumes higher amount of electrical
power
Lower power consumption
Lower luminous efficacy Higher luminous efficacy
Less expensive
Initial cost is higher compared to
Halogen lamps
Lower lifespan (Average 10,000 hours)
Lifespan is much greater than other types
of lamps (Minimum 100,000 hours)
Higher LLF (Light Loss Factor) Very low LLF (Light Loss Factor)
Switching on and off reduces the
lifespan
Switching has no effect on the lifespan
Light output decreases with time Light output does not change over time
Operating temperature is high
(Greater than 250⁰C)
Lower operating temperature
(Less than 60⁰C)

77. Annex 5 (Continued)
xxvi
Before moving into further details it is worthwhile to elaborate meanings of some of the
technical terms referred in Table 1.1. Lumen (lm) is the SI unit to measure the light output of
a light source. Luminous efficacy is the amount of light emitted per unit power consumed. It
should be noted that LED lamps are capable of emitting a higher amount light per watt. Light
loss factor is the ratio between the amount of light received by the working surface and the
amount of light emitted by the light source. Most of the light emitted by halogen lamps having
higher LLF are wasted.
Having decided that the performance of LED overrules that of halogen lamps; it is suitable to
choose the correct power rating for a LED lamp that could replace a 400W halogen lamp. The
amount of lumens delivered as well as power consumption become key factors for selection
criterion.
Table 1.2 Technical specifications of LED lamps
Input Wattage 100W 150W 200W
Input Voltage Range (V) 100-277V 100-277V 100-277V
Delivered Lumens (lm) 12000lm 18000lm 24000lm
Efficacy (lm/W) 120lm/W 120m/W 120m/W
Color Rendering Index
(CRI)
80 80 80
Color Temperature 3000-6500K 3000-6500K 3000-6500K
Beam Angle 120⁰ 120⁰ 120⁰
Power Factor 0.95 0.95 0.95
Life span (Hours) 50000hours 50000hours 50000hours
Warranty (Years) 5 years 5 years 5 years
Referring to Table 1.2 it should be noted that 150W, 18,000lm LED lamp should be a more
appropriate selection as it compensates for light output as well as the light output. Although a
halogen lamp is rated to provide a light output of 22,000 lumens, the value drops down to

78. Annex 5 (Continued)
xxvii
15,400 lumens after long hours of operation. But the output of a LED lamp is least affected by
longer duration of usage, thus emitting almost 18,000 lumens.
2. Theoretical calculations
2.1. Appropriate space to height ratio
The lamps must be properly spaced within the work area so that light is evenly distributed.
The most adequate range for space to height ratio is the range between 0.9 and 1.2 according
to the most recent standards.
0.9 < SH < 1.2
Since the maximum mounting height suitable for the workshop is about 10m, the
corresponding range for spacing between adjacent lamps is given by;
0.9 x 10m < D < 1.2 x 10m
9m < D < 12m
Therefore the spacing between two adjacent lamps can be selected to be 10m.
2.2. Providing adequate illumination
Apart from the power consumption of a light source, another factor that needs to be
considered is the level of illumination produced. The illumination is given by the
equation,
𝐸 =
∅ 𝑋 (𝑈𝐹) 𝑋 (𝐿𝐿𝐹)
𝐴
Where E = Illumination (lm/m2
)
∅ = no. of lumens emitted
UF = Utilization factor
LLF = Light loss factor
A = Total surface area of the workspace
For 32 halogen lamps ;
∅ = (22000 x 0.7 lm) x 32 = 492,800 lm
A = 140m x 15m = 2100m2
Calculation of UF:
Room reflectance is considered to be Ceiling 0.50, wall 0.30, floor 0.2

79. Annex 5 (Continued)
xxviii
Room index is calculated from the equation, 𝑅 =
𝐿 𝑥 𝑊
𝐻 (𝐿+𝑊)
where L = length of the
room, W = breadth of the room and H= mounting height.
𝑅 =
140 𝑥 15
10(140+15)
= 1.35
From the above table, UF =0.50
𝐸 =
492,800𝑙𝑚 𝑋 (0.50) 𝑋
1
1.5
2100 𝑚2 = 78.2 lm/m2
Similarly for 32 LED lamps, E =
18000𝑙𝑚 𝑋 32 𝑋 (0.50) 𝑋
1
1.5
2100 𝑚2 = 91.43 lm/m2
Therefore, LED lamps produce 17% more illumination than halogen lamps.

80. Annex 5 (Continued)
xxix
3. Observations
Time : from 1.30 p.m. to 2.00 p.m.
With lamps on
Location Light intensity (lux)
Injector room entrance 235
Pumps section 270
T/Charger section 265
Storm valve section 210
Coolers section 360
Valves section 225
Main engine section 200
Average intensity 252.1
Time : from 12 p.m. to 12.30 p.m.
Without lamps
Location Light intensity (lux)
Injector room entrance 85
Pumps section 95
T/Charger section 130
Storm valve section 150
Coolers section 175
Valves section 75
Main engine section 100
Average intensity 115.7

81. Annex 5 (Continued)
xxx
5. Cost analysis for replacement of lamps
The below Table 2.1 provides a cost analysis for the replacement of halogen lamps currently
being used at the workshop.
Table 2.1. Cost analysis for replacement of halogen lamps with LED lamps
Halogen lamp LED lamp
Technical details
Power Consumption (W) 400 150
Initial lumens 22,000 18,000
Life time 10,000 50,000
Cost of unit power (Rs. Per kWh) 9 9
Unit price of a lamp fixture (Rs.) 3,000 14,793
Operating conditions
Lumens after 5000 operating hours 15,400 18,000
working hours per year 4,450 4,450
Operating lifespan (Years) 2 11
Cost analysis
Running cost (per year) 512,640 192,240
Running cost for 5 years 2,563,200 961,200
Expenditure for fixture or replacement (Rs.) 192,000 473,376
Total cost after 5 years 2,755,200 1,434,576
Savings per year (Rs.) 320,400
Savings after replacement of Halogen
lamps with LED
1,320,624
Working hours have been calculated by considering 10 hours operation per day for 325 days
per year added with 12 hours night shift operation for 100 days per year. Therefore the
average working hours become 4450 hrs per year. The above calculations have been done
for 32 lamps installed in the workshop. During the five years’ time, halogen lamps must be
replaced twice and the replacement cost is also added to the total expenditure. The operating
lifespan has been calculated by dividing the rated life time (in hours) by the no. of operating
hours per year. Although the initial cost installing LED lamps is considerably high, it is still
capable of providing a cost reduction of 1.3 million rupees in 5 years’ time.

82. Annex 5 (Continued)
xxxi
6. Utilization of natural light
Another method of designing an efficient lighting system is to utilize natural light received
from the sun.
 Average intensity of light received by earth = 1050Wm-2
The above value of intensity varies slightly during various seasons of the year. For an
example, intensity of light received during January is 3.3% higher in January. The
luminous efficacy of daylight is 93 lumens per watt. Therefore,
 Illuminance received from sunlight per unit area= 1050 x 93 lm/m2
= 97650 lm/m2
 Illuminance received from 32 Halogen bulbs = 15400 lm x 32 = 492800 lm
 Area of a treatment sheet = 4×8 ft2
= 4×30cm ×8×30cm
= 2880 cm2
= 0.288 m2
 Let, no. of treatment sheets required = n
By equating the illuminance received from 32 Halogen bulbs (400W) to that of sunlight
received through roofing sheets,
 97650 lm/m2
× 0.7 x 0.288 m2
x n = 492800 lm
n =
492800
19686.24
n = 25.03 → n ≈ 26
Approximately 26 treatment sheets are required to replace the usage of 400W halogen
lamps with adequate daylight. In the calculation it is considered that 70% of the light
refracts through a treatment sheet.These treatment sheets are manufactured within
Colombo dockyard itself. Therefore the manufacturing cost of a sheet is Rs. 4300.00
 Cost of treatment sheets required to replace halogen lamps = Rs. 111,800
If daylight is used in this manner from 8.00 a.m. to 4 p.m. for approximately 8 hours per
day, then
 Total no. of hours in which daylight is used per year = 8 x 300 = 2400 hours
 Amount of power consumed by 32 halogen lamps = 0.4kW x 2400 h x 32
= 30,720kWh
 Cost of savings by utilizing daylight = 30720kWh x Rs.9 = Rs. 276, 480

83. Annex 6
xxxii
PRELIMINARY CALCULATION REPORT
DESIGN OF RAMP
PROJECT NC_242
40 PAX-2T DECK CARGO FERRY

84. Annex 6 (Continued)
xxxiii
1. Determination of maximum cable tension
By taking moments about the hinge,
2T x LSin α –Mg x
L
2
𝐶𝑜𝑠 𝜃 = 0
Where T=Cable tension, M= Mass of the ramp
Considering the trigonometric relationships, α and θ are related as mentioned below.
Tan(𝛼 + 𝜃) =
ℎ + 𝐿𝑠𝑖𝑛𝜃
𝐿𝐶𝑜𝑠𝜃
𝛼 = Tan−1
[
ℎ + 𝐿𝑠𝑖𝑛𝜃
𝐿𝐶𝑜𝑠𝜃
] −𝜃
Where h= height of the supporting pole, L= Length of the ramp.
Figure 1.1 Forces acting on the ramp while lifting/lowering
T=
Mg Cosθ
4𝑆𝑖𝑛𝛼

85. Annex 6 (Continued)
xxxiv
From the equations derived, the inclination of the ramp at which the cable tension becomes a
maximum can be determined from a graph.
From the graph it is clear that Tension is maximum at θ = 45⁰.
 Determination of maximum tension
Details:- h=2m (Can be varied), L=2m (fixed value), M=300kg (fixed value)
𝛼 = Tan−1
[
2 + 2𝑠𝑖𝑛 45°
2𝐶𝑜𝑠 45⁰
] −45⁰
𝛼 = 22.5⁰
T=
Mg Cosθ
4𝑆𝑖𝑛𝛼
=
(300𝑘𝑔)(9.81𝑚𝑠−2) cos 45⁰
4 𝑠𝑖𝑛22.5°
T = 1359.5 N
Tmax ≈ 1360 N

86. Annex 6 (Continued)
xxxv
2. Pulley Design
Figure 2.1 Forces acting on a vertical pulley
Resultant force acting on the pulley:
R = √𝑇1
2
+ 𝑇2
2
− 2𝑇1 𝑇2 𝐶𝑜𝑠𝛼
By taking the frictional loss into account, the relationship between the two tensions is
given by;
T2 = 𝑇1 𝑒 𝜇𝛼
R= 𝑇1√1 + 𝑒2𝜇𝛼 − 2𝑒 𝜇𝛼 𝑐𝑜𝑠𝛼
Where μ= Kinetic coefficient of friction, and α =angle of contact
From this relationship, the variation of resultant force on the pulley with ramp
inclination can be plotted as shown in fig 2.1. Assumptions for calculations are
mentioned below.
 The material of pulley and cable is Steel.
 All contact surfaces are well lubricated.
For a well lubricated, Steel on Steel contact; the kinetic coefficient of friction is
approximately 0.2 (refer annex 1)

87. Annex 6 (Continued)
xxxvi
Figure 2.2 Graph of ramp inclination vs. pulley force
The above graph has been plotted for all real values of ramp inclination θ within the range -180⁰
to +180⁰. But in this application, θ ranges between -45⁰ and +45⁰; anti-clockwise direction being
considered as positive. From figure 2.2, and figure 2.3 the highest resultant force occurs at -45⁰ for
the above specified range. For the pulley arrangement shown in figure 2.3, tension along the cable
can be calculated from below equations.
T1= 1360 N T4 = T3 𝑒 𝜇
𝜋
2
T2 = T1 𝑒 𝜇𝛼
T5 = T4 𝑒 𝜇𝛼
T3 = T2 𝑒 𝜇
𝜋
2 T6 = T5 𝑒
𝜇[𝛼+
𝜋
2
]

88. Annex 6 (Continued)
xxxvii
Figure 2.3 Plan view of the pulley arrangement

89. Annex 6 (Continued)
xxxviii

90. Annex 6 (Continued)
xxxix
Ramp inclination
Ramp inclination 45⁰ -45⁰
Tension Magnitude (N) Magnitude (N)
T1 1360.0 563.1
T2 1471.1 609.1
T3 2014.1 834.0
T4 2757.6 1141.8
T5 2982.9 1235.1
T6 4417.5 2140.2
Kg-force 675.5 327.3
Resultant force (N)
Ramp inclination θ=45⁰ θ= -45⁰
Fixed pole
Pulley 1 (vertical) 563.0 652.4
Pulley 2 (Horizontal) 2494.2 1032.7
Winch pole
Pulley 3 (Horizontal) 3414.8 1413.9
Pulley 4 (Vertical) 1141.5 1322.8
Table 2.2 Resultant force acting on each pulley
Table 2.1 Magnitudes of tension along the cable
Magnitude (N)
T1 1360.0
T2 1471.1
T3 2014.1
T4 2757.6
T5 2982.9

91. Annex 6 (Continued)
xl
3. Strength calculations for supporting poles
The pole that bears the pulley is critically loaded compared to the other fixed pole, and
therefore it has been chosen for design calculations. Design considerations to choose a
suitable pipe size for the supporting pole are as follows.
 Pipe material:- Corrosion resistivity and weldability
 Buckling stability
 Shear failure
Pipe material:- Galvanized steel
3.1.Buckling stability
One end of the supporting pole is fixed and the other end is free. The mode of
buckling is illustrated in figure 3.1. The minimum value of force that will cause
buckling failure is given by the below equation.
Pcr =
𝜋𝐸𝐼
4𝐿2
Where, Pcr = Critical force
E= Young’s modulus
I = Second moment of area of cross section
L= Length of the pole
Figure 3.1 Mode of buckling

92. Annex 6 (Continued)
xli
From the values of cable tension tabulated in table 2.2, the vertical component of
force acting on the pole is calculated as follows.
In order to avoid buckling, Pcr < 11.1 kN
𝜋𝐸𝐼
4𝐿2 < 11.1 kN
I < 11.1kN x
4𝐿2
𝜋𝐸
Data:- E= 200 GPa for galvanized steel, L= 2m
Then, I < 2.8266 x 10 -7 m4
Fy = 2982.9 Sin 22.5⁰ + 4417.5
= 5559.0 N
Moment = (4417.5 − 2982.9) 𝑥 0.2
= 107.6 Nm
With a safety factor of 2,
Downward vertical force = 11.1 kN
Moment = 215.2 Nm
Figure 3.2 Forces acting on main pulley

93. Annex 6 (Continued)
xlii
Lubricated Coefficient of Sliding Friction
Material 1 Material 2 Static Kinetic
Cast Iron Cast Iron - 0.07
Cast Iron Oak - 0.08
Copper Mild Steel - 0.18
Glass Glass 0.1 - 0.6
0.09 -
0.12
Nickel Nickel 0.28 0.12
Nickel Mild Steel - 0.18
Oak Oak (cross grain) - 0.07
Steel (mild) Cast Iron 0.18 0.13
Steel Copper Lead Alloy 0.16 0.15
Steel (mild) Lead 0.5 0.3
Steel (mild) Phos. Bros - 0.17
Steel (mild) Steel (mild) -
0.09 -
0.19
Steel (hard) Steel (hard)
0.05 -
0.11
0.03 -
0.12
Teflon Steel 0.04 0.04
Teflon Teflon 0.04 0.04

94. Annex 6 (Continued)
xliii