This document provides details about Anchor Handling Tug Supply (AHTS) vessels. It discusses that AHTS vessels are specialized offshore support vessels used to handle anchors for oil rigs and platforms, tow them into position, and provide supply services. The document outlines the key functions of AHTS vessels including towing, supply operations, anchor handling, firefighting and describes rules and regulations they must follow. It also discusses design features of AHTS vessels like their ability to carry cargo in tanks and on deck, propulsion systems, and notes they are customized for anchor handling and towing but can also perform supply duties and emergency response.

1. PROJECT REPORT
AHTS
DEPARTMENT OF SHIP TECHNOLOGY
COCHIN UNIVERSITY OF SCIENCE &
TECHNOLOGY COCHIN-682022 2023
Submitted by :-
Name : G.K AZAD
Roll no : 21519011
Sem VII
Department of Ship Technology

2. Contents
INTRODUCTION………………………………………………………………………………………4
1.1.1 what is AHTS ………………….…………………………………………………………….….3
1.1.2 Types of Supply………………………………………………………………………………...6
1.1.3 Other Functions ………………………………………………………………………………..7
1.1.3.1 Towing …………………………………………………………………………………7
1.1.3.2 Supply Operation……………………………………………………………………..8
1.1.3.3 Anchor Handling……………………………………………………………………...8
1.1.3.4 Fire Fighting…………………………………………………………………………11
1.2.1 Some Special Features of AHTS……………………………………………………………11
1.3.1 Rules to be followed…………………………………………………………………………..13
1.4.1 Application………………………………………………………………………………………15
Fixing Main Dimensions .........................................................................................................18
2.1 Parent ship analysis ....................................................................................................24
2.1.1 Determination Of dimensionless ratio: ...................................................................25
2.2 Determination of Main Particulars: ..............................................................................31
2.3 Preliminary Stability Check..........................................................................................33
2.4 Freeboard Check.........................................................................................................38
2.5 Preliminary Resistance Check.....................................................................................41
2.6 Preliminary Volume Check ..........................................................................................45
Hull Geometry.........................................................................................................................48
3.1_Offset generation..........................................................................................................49
3.2_Bonjean calculations ....................................................................................................57
Bonjean Area Table .........................................................................................................58
Bonjean Moment Table....................................................................................................59
Bonjean Curves ................................................................. Error! Bookmark not defined.
3.3_Hydrostatic Calculations...............................................................................................61
Hydrostatics Table ...........................................................................................................62
Hydrostatics Curves.........................................................................................................62

3. CHAPTER1 INTRODUCTION

4. INTRODUCTION
The deep-water oilfield market is becoming more important as the conventional oilfield
market in shallow water cannot meet the energy requirements from the consuming
market. Anchor handling tug supply vessel, hereafter it is called AHTS, is one of the
main types of OSVs and can carry out several major operations like towing, anchor
handling, supply, standby and so on offshore
In the oilfield of North Sea or many other areas in the world, a kind of special vessel is
busy with various tasks which are relative to exploration and operation of oil and gas
on offshore. This ship type has been given a variety of names but Offshore Support
Vessel (OSV) is perhaps the more dominant one. According to Guidelines for design
and construction of OSVs (2007), OSV is defined as a vessel - “which is primarily
engaged in the transport of stores, materials and equipment to offshore
installations, and - which is designed with accommodation and bridge erections
in the forward part of the vessel and an exposed cargo deck in the aft part for
the handling of cargo at sea”.
Unlike conventional cargo ships, both the unique design features and service
characteristics differ from those of conventional cargo ships and specific safety
requirement are introduced to OSVs.Those old vessels, fishing boats are used to
supply offshore platforms with fresh water, fuel, food and materials for production. In
following decades, purpose-built vessels to supply offshore rigs and platforms were
designed and well developed. With the strong desire for energy and the development
of activities on deep water, OSVs are playing an increasing important role on the
development of exploration and operation activities about oil and gas on offshore. In
the past, the sizes of OSVs are traditionally in the range of 40m to around 70m and the
types of cargos carried on board were typically casings, pipes, machineries, equipment
for offshore installations and so on.
Within the main hull of OSVs, deep tanks are typically provided for OSVs for the
carriage of drilling water, liquid mud and brine, etc. While new generation

5. OSVs are required to provide more complicated support services to deep-water drilling
operations. They are larger in size as compared to their predecessors for the purpose
of providing larger deck areas and allow bigger under deck spaces for loading
increasing number of bulk tanks for liquid mud, brine and cement, etc. OSVs can be
divided into several main types according to its functions: AHTS, PSV, Ice breakers,
and so on. Figure 1.2 shows some types of OSVs.
Different types of OSVs possess different functions and equipped with appropriate
equipment on the base of applying to requirements and specifications of maritime
organizations and specific working environment.
1.1.1 What is an AHTS?
The anchor handling tug is a naval vessel that is solely concerned with the objective
of either tugging or towing an oil-rig or a ship. When it comes to oil rigs, these tugs
form the most important necessity as without their help, it would be impossible to place
oil rigs in the required sea and oceanic areas. As the main type of OSVs, AHTS vessels
have been putting concentration on offshore activities. AHTS is a kind of Multipurpose
Offshore Service Vessels intended for towing of floating objects in open waters and
objects on sea bed, subsurface deployment and lifting of anchoring equipment and
supply services. According to the statement of Globalsecurity.org (2011), “An Anchor-
Handling Tug [AHT] moves anchors and tows drilling vessels, lighters and similar
vessels. An Anchor-handling Tug/Supply [AHTS] is a combined supply and anchor-
handling ship. An Anchor is a heavy hooked instrument which, when lowered to the
seabed, holds a vessel in place by its connecting cable. An Anchor Handling Tug is a
tug equipped with a winch to lift a working barge's anchors. It is also often used as the
working barge's tow tug. An Anchor Pendant is a wire which is attached to the crown
of an anchor, enabling it to be pulled out of the seabed. The pendant wire is used by
the anchor handling tug to set and retrieve anchors using the cable eye on the free
end of the wire”.
“An AHTS is an offshore supply vessel specially designed to provide anchor handling
services and to tow offshore platforms, barges and production modules/vessels. The
vessels are also often used as standby rescue vessels for oilfields in production”. The
description of AHTS is stated like this according to Global Security.org (2011). The
AHTS is then often equipped for fire-fighting, rescue operations and oil recovery. The
AHTS is also used in general supply service for all kinds of platforms, transporting
both wet and dry cargo in addition to deck cargo. The focus has been on the vessels'
winch and engine capacities as oil activity has moved into deeper and deeper water
in order to offer the oil companies a safe and efficient operation in the challenging
conditions of the deep-water area. (globalsecurity.org, 2011).Figure 1.3 is a kind of
AHTS type made by Damen Shipyard.

6. AHTS Vessel At Sea

7. 1.1.2 TYPE OF SUPPLY
Normally cargo is carried on the flat afterdeck and in the tanks below this. The main
types of cargo carried by an OSV are as follows:
1. Cement and other bulk commodities are transported through inbuilt pressure
tanks. Cement is discharged from the ship to the rig by means of flexible pipes and
compressed air.
2. Several hundred tons of mud are also carried.
3. Pipes of various diameters. The pipe diameter ranges from 5” to 30”.
4. Casings are normally transported to the oil rig in 12 m length.
5. Fresh water, drinking water, fuel, and lubricant oil.
6. Containers for cargo.
7. Other material to be transported are:
a) Gas containers for welding etc.
b) Drill bits and equipment for well logging.
c) Cementing equipment
d) Oil pipes.
e) Refrigerated containers.
Table 1.1 Basic Functions of AHTS
Functions Cargo/Materials
Carry cargo in bulk Barite, Cement
Carry deck cargo Containers, Drill Pipes, Casings Etc.
Cargo liquid bulk
Fuel oil, Oil Based Mud, Base Oil, Drill Water,
Portable water etc.
Towing operations Rig Moves, Barges, Productions Platforms etc.

8. 1.1.3 OTHER FUNCTIONS
1.1.3.1 TOWING
The towing objects are usually drill rigs, barges, and pontoons. Necessary
bollard pull must be evaluated considering winds and tide data for the intended
towage rate and exposed area of towed objects to wind and sea.
The reference load used in the design and testing of the towing winch is twice
the static bollard pull.

9. 1.1.3.2 SUPPLY OPERATIONS
The supply operation is a simple operation. The vessel approaches
the rig and depending upon the prevailing weather and tide conditions, it drops its
own anchor. After that it swings around and manoeuvres astern to the rig in
position where mooring ropes can be lowered by crane and used to secure to the
belt on its port and starboard quarters.
The rig crane unloads the deck cargo. It requires any of the pumpable
commodities available, it lowers hose and pumping is commenced as soon as
possible. On the completion of the unloading and after receiving back load from
the rig, the vessel lets go the mooring ropes which are again recovered by the
crane. The vessel then recovers its own anchors and returns to the base port.
In recent years, the importance of limiting emissions to air and discharges to sea
with a potential for adverse effect has become increasingly focused on both from
the society and public. This focus has caused a trend among leading companies
within the industry to implement an environmental management system, for
instance such as the ISO 14001. ‘Clean design’ is a voluntary Environmental
Class Notations introduce by DNV to award owners and operators who choose to
design and operate their ships in an environmentally sustainable manner. Recent
years it has been found that all 50% of offshore support vessel which are newly
constructed are ‘Clean Design’ due to pressure from oil company requirement.
1.1.3.3 ANCHOR HANDLING
Most of the offshore rigs and platforms don’t have their own anchor
handling mechanism which recommends for a vessel with anchor handling
abilities. These vessels can place the anchor and retrieve them with the high-
power anchor handling winch placed on the main deck. A typical anchor
handling operation is shown below

12. 1.1.3.4 FIRE FIGHTING
The vessel shall have capabilities for early-stage firefighting and
rescue operations close to structure on fire. Fire monitors, equipment, and
other machinery mandatory for this shall be accommodated on board.
1.1.3.5 Fire fighters 1 (or 2 or 3) are class notations granted to vessels built
and equipped in compliance with the relevant class requirements. The following
matters are covered:
1.1.3.6 The vessel’s firefighting capability
1.1.3.7 The vessel's stability and its ability to keep position when the fire
fighting monitors are in operation.
1.1.3.8 The vessels’ ability for self-protection.
1.2.1 SOME SPECIAL FEATURES OF AHTS:
• Operational difficulties are faced due to numerous pumps and valves to
handle. There are three tier of tanks one over another.
• An AHTS does not require much of cargo handling facilities, because
-The deck cargo on the open deck is discharged by large cranes on board
the rig. - Pumps are used for fuel oil, rig water etc.
-Air compressor for discharging bulk.

13. • Cranes may be provided on AHTS.
• Propulsion is diesel engine with Controllable Pitch Propellers (CPP)
having Kort nozzle. As vessel has to tow as well as act as supply vessel,
CPP is vital.
• Usually, one or two rigs are supplied at same time.
• Helipad facility is an additional feature and not required in all AHTS.
The wheel house is designed to ensure excellent all-round view as far as possible.
Unobstructed view of the tow winch, aft deck and aft overhead is ensured by flitting
lower level and deck head windows. The accommodation is well appointed and
centrally air-conditioned. The main propulsion engines are usually two medium speed
heavy duty marine diesels.

14. 1.3.1.1 RULES TO BE FOLLOWED
• Rules and regulation of the port of registry
• Rules and regulations of the classification society
• IMO rules and regulations
• International Convention on load line 1966 and amendments
• International conventions on tonnage measurements of ships-1969
• SOLAS-1974 and amendments
• International Convention for prevention of collision at sea-1972 and
amendments.
• MARPOL 73/78 and amendments
• ISO standard No 6954- Guidelines for the overall evaluation of vibration in
merchant ships.
• IEC Publication 92- Electrical Installation in ship.

15. ADDITIONAL READING
Anchor Handling Tug Supply Vessels are predominantly built to handle anchors for oil
rigs, tow them to different locations and to secure the rigs in place. AHTS Vessels also
serve as Emergency Response and Rescue Vessels (ERRVs).
The oil rigs are either located in the middle of the ocean or in the deep seas, however, the
question is what type of vessels help such oil rigs reach the middle of the ocean? The
answer is anchor handling tug supply vessel (AHTS Vessels Manufacturers USA)
Many of these vessels are designed for the harsh conditions of the North Sea and they
can undertake supply duties between land bases and drilling sites. They can also be used
for towing assistance during tanker loading, deep water anchor handling and towing of
threatening objects.
AHTS Vessels differ from Platform Supply Vessels (PSVs) in being fitted with winches for
towing and anchor handling and having more power to increase the bollard pull. This
machinery is specifically designed for anchor handling operations. They also have
arrangements for quick anchor release, which can be operated from the bridge or other
normally manned location which directly communicates with the bridge.
Even if AHTS-vessels are customized for anchor-handling and towing, they can also handle
ROV (remotely operated underwater vehicle) services, safety/rescue services and also supply
duties between the mainland and offshore installations.
ADVANTAGES OF AHTS VESSELS-
 AHTS vessels have superior bollard pull and a higher engine rating which makes
them powerful enough to be utilized for specialized jobs such as Anchor Handling.
 They are fitted with multiple thrusters providing tremendous vessel handling
features that allow such vessels to work in any sea condition.
 A large amount of strengthened deck space allows even the largest of the anchors,
heavy wires, chains, buoys and other related equipment to be stored and handled.
 AHTS have an extremely powerful multi-drum system with twin winches, each for
towing and anchor handling purposes. Apart from this, it has the combination of
other spare drums and work winches which are especially used for towing and deep-
water anchor handling.
 Sufficient amount of anchor chain can be stored on board due to the availability of
larger capacity chain lockers.
 AHTS are multipurpose vessels that can even perform the functions of ordinary
supply boats such as carrying a large quantity of water, fuel and deck cargo.

16. 1.4.1 APPLICATIONS OF AHTS VESSELS
 AHTS are used as multipurpose workboats in the oil as well as the gas offshore
field.
 They are used for towing operations, rig moves, for carrying dry and liquid cargo
such as cement, mud, fresh water, fuel oil, etc.
 If the ocean-going tugs are not readily available, then these can take up to the role
of salvaging and rescue.
 Anchor work for rigs, barges, semi-submersibles, construction barges, etc can be
executed with the help of these vessels. These vessels can perform efficiently in the
roughest sea conditions and also in very deep waters.
 Installation of buoys, SBM mooring, sub-sea moorings is ideally done with the help
of the Anchor Handling Tugs.
 Nowadays, they are progressively being used for towing and anchor handling of
newer offshore structures such as the Tension Leg Platforms (TLPs) or even the
gravity-based platforms.
IMPORTANCE OF AHTS VESSELS
AHTS provides multi-utility facilities. Oil drilling from oceanic areas has increased and has
become a regular activity. Hence, its demand is increasing day by day. These vessels are
one of those technological creations of the marine world that also help in preventing major
mishaps at the sea.
ADDITIONAL FEATURES
Anchor handling tug vessels have crane-like equipment (known as the winch) that can be
attached to the oil rigs and then, propelled forth in the water. The “anchor supply “, mentioned
as a part of the vessel’s name is then allowed to be sunk into the sea water so that it keeps
the rigs steady.
Restrictions of these vessels are based upon the type of work to be carried out such as –

17. 1. They can be restricted to handle large construction or cargo barges when operating in
confined spaces.
2. Since they are more often than not confused with the harbour tugs, these vessels are
not designed to push other vessels either alongside or at sea.
3. These vessels have a limited pulling power for which the towing gears steel deck
fittings, tow points and other suitable towing assemblies have to be strong enough in order
to perform effortlessly.
Since such jobs are difficult and could endanger lives, taking short cuts, working
impatiently, building up frustration and reacting complacently have to be isolated. The Master
and the Crew of such workhorses, hence, have to remain alert at all times and portray swift
and positive reactions to avert catastrophic consequences.

18. Chapter - 2
Fixing Main Dimensions

19. GENERAL FEATURES OF AN AHTS:
 Operational difficulties are faced due to numerous pumps and
valves tohandle.
 Requirement of a high-power anchor handling winch and other
anchorhandling equipment (A-frames, cranes etc.)
 The deck loading on the open deck are discharged by large cranes on board the rig.
 Pumps are used for fuel oil, rig water etc.
 Air compressor for discharging bulk.
 Cranes may be provided to handle deck load and Rig Anchors.
 Propulsion is diesel with CPP having Kort nozzle. As vessel has to tow as well
as actas supply vessel, CPP is vital.
 Usually one or two rigs are supplied at same time.
 Helipad facility is an additional feature and not required in all vessels.
Functions and Requirements:
The main functions of a supply vessel with towing facility are:
 Transport of fresh water, diesel oil, bulk cement, stores, Mud, base oil,
glycol,materials, and equipment etc.
 Tow/move drilling and work over safety rigs.
 Anchor handling duties.
 Move men and materials between platforms and shore.
 Firefighting, evacuate casualties. Operations to be 24 hrs/day continuous operation.
AIM OF THE PROJECT AND MISSION ANALYSIS
The project aims to build an Anchor Handling Tug Supply (AHTS) vessel which
will carry out the above-mentioned function for the Rigs owned by ONGC in the
Krishna-Godavari basin.

20. OWNER’S REQUIREMENT
The owner’s requirements are as follows:
Table 2.1: Owner’s requirements
The design constraints/frameworks are the following:
1. Safe and reliable construction.
2. Owner’s / Charterer’s requirements to endurance, safety, and performance.
3. Requirements from Regulatory bodies and Statutory bodies.
4. Economic design (Initial cost / operating cost)
5. Efficiency in all functions (Offshore operation and cargo handling)
Based on these conditions it is up to the designer to make an efficient, well
considereddesign and at a lowest cost as possible for the operational area it shall
serve.
OPERATING AREA AND BASEPORT:
The route selected is in Krishna-Godavari offshore
Basin.The nearest port is Kakinada port
Details of the Location and Topography of Kakinada Port
⚫ Latitude: 16.56' (North)
⚫ Longitude: 82.15’. (East).
TYPE AHTS
13knots
TOWING SPEED 7 Knots
BOLLARD PULL 100t
t
RADIUS OF ACTION 710n
m

21. ⚫ Minimum Depth: 10.9 metres
⚫ Minimum Breadth: 70 metres
⚫ Topography: Natural Harbour.
Figure 2.1(a) Location of KG BASIN

22. Figure 2.1 (b) Maps of KG BASIN oil fields
Figure 2.1 (c) Maps of KG BASIN

23. RADIUS OF ACTION
It is the maximum distance by which a vessel has to travel from one port to
another place before refueling it, plus a 10% allowance. For our vessel, this route
will be:
Kakinada Port - KG DWN 98/2 – Kakinada Port
The distance from Kakinada Port - KG DWN 98/2 is around 141 nautical miles.
As refueling is possible only at the port, to and for journey has to be
considered for finding radius ofaction.
Therefore, Radius of action = [141 nm*2] +10%allowance = 310.2 nm
By considering the towing and anchor handling duties of the vessel and
considering that the vessel may have to do safety stand-by operations, the range
is taken as
710 nm with 15 days endurance.
CLASS NOTATION:
Class Notation: DNV 1A1 Tug, Supply Vessel, Fi-Fi 1, DP- AUTR, EO
 1A1: Main class notation under DNV.
 Tug: Vessel must follow the requirement given in [DNV Pt. 6 Ch. 1 Sec. 4]
 Supply Vessel: Vessel designed especially for supply services to
offshore installation.[DNV: Pt. 5 Ch. 7]
 DP AUTR: A dynamic positioning system with redundancy in technical
design and with an independent joystick back-up. Equivalent to IMO
equipment class 2. Dynamic Positioning can be described as an integration
of several shipboard systems to obtain the ability of accurate
maneuverability. [DNV Pt. 6 Ch. 7 Sec. 1]
 Fi-Fi 1: Given to vessels intended for fighting fires on offshore and
onshore structures, as well as rescue operations. Vessel will be built for
early-stage firefighting. Vessel will have capability to withstand higher heat
radiation loads from external fires. Pump capacity should be enough to
produce length of throw= 120m and height of throw= 50m.
[DNV Pt. 5 Ch. 7 Sec. 5]
 E0: Class notation E0 which is considered to meet the regulations of
the International Convention for the Safety of Life at Sea (SOLAS) for
unattended machinery spaces. [DNV Pt. 6 Ch.3]

24. 2.1_PARENT SHIP ANALYSIS
Parent Ship Data of various vessels with Comparable Overall Size, Deck-Area and Bollard Pull were chosen. The Database was
collected from ship registers of various Classification Societies like DNV, BV, LR etc and product brochure from various Offshore
Vessel Providers.
NAME LOA[m] Lbp[m] b[m] T[m] d[m] dwt[t]
bollard
pull
speed[kn] L/B L/D B/D B/T BHP
MMA
CRYSA5T
70.05 66 17 6.1 7.05 2515 102.14 14 4.120588 9.93617 2.411348 2.786885 7965
MMA
VISION
67.8 60.75 15 5 6.1 1700 105 14 4.52 11.11475 2.459016 3 8000
MMA
MONARCH
75.4 67.16 16.8 5 7.5 2193 157 14.8 4.488095 10.05333 2.24 3.36 12069
MMA
CORAL
70.05 66 17 6.1 7.5 2400 108 14 4.120588 9.34 2.266667 2.786885 8000
MMA
MAJESTIC
78.2 69 18.5 6.6 8 3500 160.7 12 4.227027 9.775 2.3125 2.80303 12070
GREATSHIP
AARTI
63 60.14 15 5.2 7.6 1650 80 14 4.2 8.289474 1.973684 2.884615 7000
GREATSHIP
ADITI
64.35 60 15 5.182 7.4 2045 80 16 4.29 8.695946 2.027027 2.894635 7100
GREATSHIP
AHALYA
63 59.26 15 5.2 7.6 1643 80 16 4.2 8.289474 1.973684 2.884615 7000
GREATSHIP
AMRITA
64.35 60.14 15 5.182 7.4 2045 80 16.5 4.29 8.695946 2.027027 2.894635 7100
GREATSHIP
ANJALI
64.35 60.14 15 5.182 7.4 2180 90.1 14 4.29 8.695946 2.027027 2.894635 7100

25. 2.1.1_DETERMINATION OF DIMENSIONLESS RATIO:
I have selected parent ships of similar bollard pull and overall structural size, collected
the data of parent ship and the dimensional ratios L/B, B/D, B/T, L/D is plotted against
deadweight. By using Linear Regression analysis, the dimension rations of the ship
are selected corresponding to the deadweight of 3000t.
BOLLARD PULL V/S L/B
By using Linear Regression analysis, for BOLLAR PULL=100T , L/B Ratio = 4.2513
For which B = 14.7352 m
y = 0.0007x + 4.1813
4.1
4.15
4.2
4.25
4.3
4.35
4.4
4.45
4.5
4.55
0 20 40 60 80 100 120 140 160 180
L/B
bollard
pull L/B
102.14 4.120588235
105 4.52
157 4.488095238
108 4.120588235
160.7 4.227027027
80 4.2
80 4.29
80 4.2
80 4.29
90.1 4.29
80 4.2
150 4.227027027
150 4.227027027

26. BOLLARD PULL V/S L/D
By using Linear Regression analysis, for BOLLAR PULL=100T , L /D = 9.1451 m
For which D = 6.8500 m
y = 0.0187x + 7.2751
0
2
4
6
8
10
12
0 50 100 150 200
L/D
bollard
pull L/D
102.14 9.936170213
105 11.1147541
157 10.05333333
108 9.34
160.7 9.775
80 8.289473684
80 8.695945946
80 8.289473684
80 8.695945946
90.1 8.695945946
80 8.289473684
150 10.02564103
150 10.02564103

27. BOLLARD PULL V/S B/D
By using Linear Regression analysis, for BOLLAR PULL=100T , B/D Ratio = 2.1454
For which D = 6.8500 m
y = 0.004x + 1.7454
0
0.5
1
1.5
2
2.5
3
0 20 40 60 80 100 120 140 160 180
B/D
bollard
pull B/D
102.14 2.411347518
105 2.459016393
157 2.24
108 2.266666667
160.7 2.3125
80 1.973684211
80 2.027027027
80 1.973684211
80 2.027027027
90.1 2.027027027
80 1.973684211
150 2.371794872
150 2.371794872

28. BOLLARD PULL V/S B/T
By using Linear Regression analysis, for BOLLAR PULL=100T , B/T Ratio = 2.8925
For which T = 5.09429 m
y = 0.0009x + 2.8025
0
0.5
1
1.5
2
2.5
3
3.5
4
0 20 40 60 80 100 120 140 160 180
B/T bollard
pull B/T
102.14 2.786885246
105 3
157 3.36
108 2.786885246
160.7 2.803030303
80 2.884615385
80 2.894635276
80 2.884615385
80 2.894635276
90.1 2.894635276
80 2.884615385
150 2.803030303
150 2.803030303

29. BOLLARD PULL V/S LOA
By using Linear Regression analysis, for BOLLAR PULL=100T , LOA = 67.469
y = 0.1861x + 48.859
0
10
20
30
40
50
60
70
80
90
0 20 40 60 80 100 120 140 160 180
LOA[m] bollard
pull LOA[m]
102.14 70.05
105 67.8
157 75.4
108 70.05
160.7 78.2
80 63
80 64.35
80 63
80 64.35
90.1 64.35
80 63
150 78.2
150 78.2

30. BOLLARD PULL V/S LBP
By using Linear Regression analysis, for BOLLAR PULL=100T , LBP = 62.644
From these Ratios, the Main Particulars of the Vessels are taken as:
LBP = 62.644 m
B = 14.7352 m
T = 5.09429 m
D = 6.8500 m
y = 0.1239x + 50.254
58
60
62
64
66
68
70
72
0 20 40 60 80 100 120 140 160 180
Lbp[m]
bollard pull Lbp[m]
102.14 66
105 60.75
157 67.16
108 66
160.7 69
80 60.14
80 60
80 59.26
80 60.14
90.1 60.14
80 60
150 70.46
150 70.48

31. 2.2 DETERMINATION OF MAIN PARTICULARS:
For the calculation of Deadweight and Displacement, the method specified in the RINA
Transaction 1977 “Some Ship Design Methods” by Watson and Gilfillan.
Considering CB = 0.71722
Displacement Δ:
𝛥 = 𝐶𝐵 . 𝐿 . 𝐵 . 𝑇 .  . (1 + 𝑠)
where s is taken as 0.006
= 4848.9021 t
Deadweight Calculations:
Total displacement = Light ship mass + Dead weight
Light ship mass = Steel Mass + Outfit Mass + Machinery Weight
Available Deadweight = Total Mass Displacement – Lightship Mass
Steel Mass:
Steel weight for actual CB
1 at 0.8D is given by;
𝑊𝑆 = 𝑊𝑆7[1 + 0.5(𝐶𝐵
1
− 0.7)]
where;
𝐶𝐵
1
= 𝐶𝐵 + (1 − 𝐶𝐵).
(0.8𝐷 − 𝑇)
3𝑇
= 0.71722
𝑊𝑆7 = 𝐾. 𝐸1.36
K = 0.041~0.051 (for Offshore Vessels)
K is taken as 0.045
Equipment Number is given by the equation:
𝐸 = 𝐿(𝐵 + 𝑇) + 0.85. 𝐿. (𝐷 − 𝑇) + 0.85. ∑𝑙1ℎ1 + 0.75. ∑𝑙2ℎ2
= 1620.689
where, 0.85 ∑ l1h1 + 0.75 ∑ l2h2 is taken as 285
Thus,

32. WS7 = 1043.78 t
WS = 1055.9939
Machinery Weight:
𝑊𝑀 = 0.72 (𝑀𝐶𝑅)0.78
(Watson &
Gilfillan)
= 1094.192839 t
𝑤ℎ𝑒𝑟𝑒 𝑀𝐶𝑅 𝑖𝑠 𝑡𝑎𝑘𝑒𝑛 𝑎𝑠 12000 𝑘𝑊
Outfit Mass:
𝑊𝑂 = 𝐾. 𝐿. 𝐵
where K is taken as 0.3
= 276.82 t
Total Lightship Mass:
Lightship mass = 𝑆𝑡𝑒𝑒𝑙 𝑀𝑎𝑠𝑠 + 𝑂𝑢𝑡𝑓𝑖𝑡 𝑀𝑎𝑠𝑠 + 𝑀𝑎𝑐ℎ𝑖𝑛𝑒𝑟𝑦 𝑊𝑒𝑖𝑔ℎ𝑡
= 2427.0105𝑡
Available Deadweight:
Available Deadweight = Total Mass Displacement – Lightship Mass
2421.8 𝑡
Available Deadweight is more than Required Deadweight.

33. 2.3 PRELIMINARY STABILITY CHECK
The Preliminary Stability check is done using the Prochaska’s Stability Computation
Method and the parameters required to find the stability is found using empirical
relation. This method gives an empirical relation to find the GZ values.
General Criteria regarding righting lever curve properties are given below:
a) The area under the righting lever curve (GZ curve) shall not be less than 0.055
metre-radians up to φ = 30° angle of heel and not less than 0.09 metre-radians
up to φ = 40° or the angle of down-flooding φf if this angle is less than 40°.
Additionally, the area under the righting lever curve (GZ curve) between the
angles of heel of 30° and 40° or between 30° and φf, if this angle is less than
40°, shall not be less than 0.03 metre-radians.
b) The righting lever GZ shall be at least 0.2 m at an angle of heel equal to or
greater than 30°.
c) The maximum righting lever shall occur at an angle of heel not less than 25°. If
this is not practicable, alternative criteria, based on an equivalent level of safety,
may be applied subject to the approval of the Administration.
d) The initial metacentric height GM0 shall not be less than 0.15 m.
Criteria for Offshore Supply Vessels regarding righting lever curve properties are given
below:
a) The area under the curve of righting levers (GZ curve) should not be less than
0.07 metre-radians up to an angle of 15° when the maximum righting lever (GZ)
occurs at 15° and 0.055 metre-radians up to an angle of 30° when the maximum
righting lever (GZ) occurs at 30° or above. Where the maximum righting lever
(GZ) occurs at angles of between 15° and 30°, the corresponding area under
the righting lever curve should be:
0.055 + 0.001 (30° - φmax) metre-radians
b) The area under the righting lever curve (GZ curve) between the angles of heel
of 30° and 40°, or between 30° and φf if this angle is less than 40°, should be
not less than 0.03 metre-radians;
c) The righting lever (GZ) should be at least 0.2 m at an angle of heel equal to or
greater than 30°;
d) The maximum righting lever (GZ) should occur at an angle of heel not less than
15°;

34. e) The initial transverse metacentric height (GM0) should not be less than 0.15 m.
Parameters
Water Plane Area Coefficient:
𝐶𝑊𝐿 = 𝐶𝐵 (0.471 + 0.551. 𝐶𝐵)
⁄
(Parson – 2003)
= 0.828019
Vertical Centre of Buoyancy:
𝐾𝐵1 = (
5
6
−
𝐶𝐵
3.𝐶𝑊𝐿
) . 𝑇 (Normand
II)
= 2.774376 m
𝐾𝐵2 = (0.78 − 0.285
𝐶𝐵
𝐶𝑊𝐿
) . 𝑇 (Wobig)
= 2.715951 m
𝐾𝐵 = (𝐾𝐵1 + 𝐾𝐵2) 2
⁄
= 2.745163 m
Metacentric Radius:
𝐵𝑀 = 𝐶1. 𝐵2
(12. 𝑇. 𝐶𝐵)
⁄
(Papanikolaou)
= 5.218597 m
Where,
𝐶1 = 0.096 + 0.89. 𝐶𝑊𝑃
2
(Normand)
= 0.706197
Vertical Centre of Gravity:

35. 𝐾𝐺 = 𝑘𝐷. 𝐷
(Papanikolaou)
= 4.4525 m
Where,
𝑘𝐷 𝑖𝑠 𝑡𝑎𝑘𝑒𝑛 𝑎𝑠 0.65 (𝐹𝑜𝑟 𝑆𝑚𝑎𝑙𝑙 𝐶𝑎𝑟𝑔𝑜 𝑉𝑒𝑠𝑠𝑒𝑙 𝑘𝐷 = 0.6~0.8)
Metacentric Height:
𝐺𝑀 = 𝐾𝐷 + 𝐵𝑀 − 𝐾𝐺
= 3.51126 m
GZ Curve
The GZ values are obtained from the equation,
𝐺𝑍 = 𝐺𝑀. 𝑠𝑖𝑛ɵ + 𝐵𝑀. 𝐶𝑅𝑆

36. The CRS values are obtained from the Prohaska’s Chart given below:
ɵ
(deg)
ɵ
(rad)
sin ɵ GM
(m)
BM
(m)
CRS GZ
(m)
0 0 0 3.51126 5.218597 0 0
15 0.261799 0.258819 3.51126 5.218597 -0.04 0.700037
30 0.523599 0.5 3.51126 5.218597 -0.2 0.711911
45 0.785398 0.707107 3.51126 5.218597 -0.4 0.395397
60 1.047198 0.866025 3.51126 5.218597 -0.6 -0.09032
75 1.308997 0.965926 3.51126 5.218597 -0.7 -0.2614
90 1.570796 1 3.51126 5.218597 -0.8 -0.66362

37. The GZ Curve thus obtained is given below:
General Criteria regarding GZ curve properties
Characteristics IMO requirements Result P/F
Area under GZ curve
upto 30°
Area should be
greater than
0.055m.rad
0.20711m.rad P
Area under GZ curve
upto 40°/ φf
Area should be
greater than
0.09m.rad
0.28356m.rad P
Area under GZ curve
between 30° and 40°/
φf
Area should be
greater than
0.03m.rad
0.07645m.rad P
Right Lever GZ at φ
equal to or greater
than 30°
GZ should be greater
than 0.2
0.5076m P
Maximum Righting
Lever GZ Occurs at φ
Angle should be
greater than 25°
23.59275° F
Initial Metacentric
Height GM0
GM0 should not be
less than 0.15m
2.39647m P
y = -5E-09x5 + 9E-07x4 - 4E-05x3 - 0.0006x2 + 0.0617x + 0.002
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
0 10 20 30 40 50 60 70 80 90 100
Chart Title Angle
(deg) GZ
0 0
15 0.700037
30 0.711911
45 0.395397
60 -0.09032
75 -0.2614
90 -0.66362

38. Criteria for Offshore Supply Vessels regarding GZ curve properties
Characteristics IMO requirements Result P/F
Area under GZ curve
upto 15°
Area should be
greater than
0.07m.rad
0.07006m.rad P
Area under GZ curve
upto 30°
Area should be
greater than
0.055m.rad
0.20711m.rad P
Area under GZ curve
between 15° and 30°
Area should be
greater than
0.06141m.rad
0.13704m.rad P
Area under GZ curve
between 30° and 40°
Area should be
greater than
0.03m.rad
0.07645m.rad P
Maximum Righting
Lever GZ Occurs at φ
Angle should be
greater than 15°
23.59275° P
Conclusion
The stability criteria are satisfied in accordance to Prohaska’s method.
2.4 FREEBOARD CHECK
All ships (with certain exceptions) are required to be surveyed and marked with
permanent load line markings in accordance with the International Convention on Load
Lines (ICLL), 1966 as modified 1988. The Principle Purpose of load line assignment
is to ensure that the ship always has sufficient reserve buoyancy and intact stability
when proceeding to sea. Reference is made to Part 3 of the IMO publication ‘Load
Lines – 2002 Edition’ that details the procedure for the calculation and assignment of
freeboards. Freeboard influences the following: -
 Reserve buoyancy
 The angle of deck immersion
 The stability at large angle of heel
AHTSs are classified as type B ships. The steps involved in freeboard check are:
 Calculate tabular freeboard from the table
 Calculate the correction for CB
 Calculate the correction for depth
 Calculate the correction for sheer
 Calculate correction for superstructure
 Calculate final freeboard from above results

39. Standard Tabular Freeboard:
L (in m) Freeboard (in mm)
62 600
From IMO regulation 28
Correction for CB,0.85D >0.68 (Regulation 30)
CB = 0.71722
𝐶𝐵,0.85𝐷 = 𝐶𝐵 + (1 − 𝐶𝐵).
(0.85𝐷 − 𝑇)
3𝑇
= 0.7307
𝐹
𝑛𝑒𝑤 = 𝐹𝑠𝑡𝑑.
(𝐶𝐵,0.85𝐷 + 0.68)
1.36
=622.3678mm
Correction for Depth (Regulation 31)
𝐿
𝐷
< 15 (𝑎𝑠
𝐿
𝐷
= 8.5)
𝑅 =
𝐿
0.48
(𝑓𝑜𝑟 𝑣𝑒𝑠𝑠𝑒𝑙𝑠 𝑙𝑒𝑛𝑔𝑡ℎ𝑠 𝑙𝑒𝑠𝑠 𝑡ℎ𝑎𝑛 120 𝑚𝑒𝑡𝑟𝑒𝑠)
= 129.1666
𝐶𝑜𝑟𝑟𝑒𝑐𝑡𝑖𝑜𝑛 = (𝐷 −
𝐿
15
) . 𝑅
= 499.0291 mm
Correction due to Superstructure (Regulation 37)
Total
Effective
Length of
Superstructu
re
0 0.1
L
0.2
L
0.3
L
0.4
L
0.5
L
0.6
L
0.7
L
0.8
L
0.9
L
1 L
Percentage
Deduction for
Type B
0 6.3 12.7 19 27.5 36 46 63 75.3 87.7 100
Effective Superstructure Length = 23.0405 m
Using Linear Interpolation,

40. Percentage Deduction here = 28.43829 % of Standard Freeboard
𝐶𝑜𝑟𝑟𝑒𝑐𝑡𝑖𝑜𝑛 = 193.3804 𝑚𝑚
Correction due to Sheer (Regulation 38)
Sheer is defined as being the curvature of the freeboard deck in a fore and aft direction.
Benefits of sheer include:
 Greater reserve buoyancy at the ends of the ship, particularly forward, ensuring
good lift in a head/following sea;
 Reduces water shipped on deck;
 Reduces risk of foredeck being submerged after collision thus improving
survivability in the damaged condition and helps to maintain an acceptable
angle of heel at which progressive down flooding takes place.
The tabular freeboards are based upon a standard sheer profile (standard ship),
measured at seven equally spaced stations along the hull. A process based on
Simpson’s 1331 Rule of area estimation is applied separately to the sheer
measurements from the aft perpendicular to amidships and the forward perpendicular
to amidships to produce measures of effective sheer aft and forward respectively.
Any deficiency in sheer will result in an increase in freeboard.
Excess sheer will result in a deduction in freeboard.
The amount of the deduction or increase in freeboard is determined by formulae in
regulation 38.
After Half
Station Ordinate (in mm) Factor
After Perpendicular 25 (L/3 + 10) 1
1/6 L from A.P 11,1 (L/3 + 10) 3
1/3 L from A.P 2,8 (L/3 + 10) 3
Amidships 0 1
Forward Half
Station Ordinate (in mm) Factor
Amidships 0 1
1/3 L from F.P 5,6 (L/3 + 10) 3
1/6 L from F.P 22,2 (L/3 + 10) 3
Forward Perpendicular 50 (L/3 + 10) 1
Where the sheer profile differs from the standard, the four ordinates of each profile in
the forward or after half shall be multiplied by the appropriate factors given in the table
of ordinates. The difference between the sums of the respective products and those

41. of the standard divided by 8 measures the deficiency or excess of sheer in the forward
or after half. The arithmetical mean of the excess or deficiency in the forward and after
halves measures the excess or deficiency of sheer.
Deficiency of Shear = 386.2097
𝐶𝑜𝑟𝑟𝑒𝑐𝑡𝑖𝑜𝑛 = 0.75 −
𝑆
2𝐿
= 181.7671𝑚𝑚
Final Freeboard requirement after Correction
𝐹𝑏 = 705.2074846 + 491.1111111 − 183.4535349 + 201.2647978
= 1109.784 𝑚𝑚
Available Freeboard = D – T
= 1.756 m = 1756 mm (More than required)
Hence Freeboard Check satisfied in accordance to ICLL 1966.
2.5 PRELIMINARY RESISTANCE CHECK
Preliminary resistance check was carried out using J. Holtrop and G.G.J. Mennen
method manually.
Coefficient of Frictional Resistance 𝐶𝐹 = 0.075 (𝑙𝑜𝑔10 𝑅𝑒
⁄ − 2)2
= 0.00174
Velocity v = 13 knots = 6.6872 m/s
Kinematic Viscosity ν = 0.00000114 m2/s
Reynolds number 𝑅𝑒 = (𝑉. 𝐿)/𝜈 = 429946268.7
Midship Coefficient 𝐶𝑀 = 1.006 − 0.0056 𝐶𝐵
−3.56
(Kerlen
1970)

42. = 0.988889
Waterplane Coefficient is taken as 𝐶𝑊𝑃 = 0.895
Transverse Sectional Area of the Bulb 𝐴𝐵𝑇 = 0
Wetted Surface Area
𝑆 = 𝐿(2𝑇 + 𝐵)√𝐶𝑀(0.453 + 0.4425 𝐶𝐵 − 0.2862 𝐶𝑀
− 0.003467 𝐵 𝑇
⁄ + 0.3696 𝐶𝑊𝑃) + 2.38 𝐴𝐵𝑇/𝐶𝐵
= 1247.4𝑚^3
Frictional Resistance (𝑹𝑭)
𝑅𝐹 =
1
2
𝑉2
𝐶𝐹 𝑆
= 396.2000302 𝑘𝑁
The Form Factor of the hull (1 + 𝑘1):
1 + 𝑘1 = 𝑐13 ∗ {0.93 + 𝑐12 ∗ (
𝐵
𝐿𝑅
)
0.92497
∗ (0.95 − 𝐶𝑃)−0.521448
∗ (1 − 𝐶𝑃 + 0.0225 𝑙𝑐𝑏)0.6906
= 1.482981483
where the parameter reflecting Length of the Run 𝐿𝑅 is given by the relation:
𝐿𝑅
𝐿
= 1 − 𝐶𝑃 + 0.06𝐶𝑃 ∗ 𝑙𝑐𝑏/(4𝐶𝑃 − 1)
= 0.264551615
𝐿𝑅 = 17.98950981
Prismatic Coefficient 𝐶𝑃 = 𝐶𝐵 𝐶𝑀 = 0.73891
⁄
Coefficient 𝑐12 = (𝑇/𝐿)0.2228446
𝑤ℎ𝑒𝑛 𝑇/𝐿 > 0.05 (ℎ𝑒𝑟𝑒 𝑇/𝐿 =
0.097)
= 0.594656575
Coefficient 𝑐13 = 1 + 0.003𝐶𝑠𝑡𝑒𝑟𝑛
= 1.03

43. where 𝐶𝑠𝑡𝑒𝑟𝑛 = +10 (for afterbody form of U-
Shape)
𝑙𝑐𝑏 = −1.6934 𝑚 𝑎𝑓𝑡 𝑓𝑟𝑜𝑚 𝑚𝑖𝑑𝑠ℎ𝑖𝑝
Appendage Resistance (𝑹𝑨𝑷𝑷):
𝑅𝐴𝑃𝑃 =
1
2
 𝑉2
𝑆𝐴𝑃𝑃(1 + 𝑘2) 𝐶𝐹
= 6.670276776 𝑘𝑁
where,
Wetted Area of Appendages is taken as 𝑆𝐴𝑃𝑃 = 52.58319
Appendage Resistance Factor is taken as (1 + 𝑘2) = 2.8
Wave Resistance (𝑹𝑾):
𝑅𝑊 = 𝑐1 𝑐2 𝑐5 𝛻  𝑔 𝑒𝑥𝑝{𝑚1 𝐹
𝑛
𝑑
+ 𝑚2 𝑐𝑜𝑠(𝜆𝐹
𝑛
−2
)}
= 156.2586361 𝑘𝑁
where,
𝑐1 = 2223105 𝑐7
3.78613
(𝑇/𝐵)1.07961
(90 − 𝑖𝐸)−1.37565
where 𝑐7 = 0.5 −
0.0625𝐿
𝐵
𝑤ℎ𝑒𝑛
𝐵
𝐿
< 0.25 (ℎ𝑒𝑟𝑒 𝐵/𝐿 = 0.23522)
= 0.47343
𝑖𝐸 = 1 + 89 𝑒𝑥𝑝{−(𝐿/𝐵)0.80856(1 − 𝐶𝑊𝑃)0.30484(1 − 𝐶𝑃 − 0.0225 𝑙𝑐𝑏)0.6367
(𝐿𝑅/𝐵)0.34574
(100𝛻/𝐿3
)0.16302
}
= 42.96025142
𝑐2 = 𝑒𝑥𝑝(−1.89√𝑐3)
= 1
where 𝑐3 = 0.56 𝐴𝐵𝑇
1.5
{𝐵 𝑇(0.31√𝐴𝐵𝑇 + 𝑇𝐹 − ℎ𝐵)}
⁄
= 0
in which ℎ𝐵 is the Position of Centre of Transverse Sectional Area of Bulb
𝐴𝐵𝑇
(due to lack of Bulbous Bow, both considered as 0)

44. Draft at Fore Perpendicular 𝑇𝐹 = 𝑇 = 6.6
𝑐5 = 1 − 0.8 𝐴𝑇/(𝐵 𝑇 𝐶𝑀)
= 1
where Immersed Part of the Transverse Area of Transom at Zero Speed 𝐴𝑇 = 0
(due to lack of immersion in the Transom Area)
𝑑 = −0.9
𝜆 = 1.446 𝐶𝑃 − 0.03 𝐿 𝐵
⁄ when L/B<12 (here
L/B = 3.778)
= 0.925508159
𝑚1 = 0.0140407 𝐿 𝑇
⁄ − 1.75254 𝛻1 3
⁄
𝐿
⁄ − 4.79323 𝐵 𝐿
⁄ − 𝑐16
= −2.822453224
where 𝑐16 = 8.07981 𝐶𝑃 − 13.8673 𝐶𝑃
2
+ 6.984388 𝐶𝑃
3
= 1.237184979 when CP<0.80 (here
CP= 0.7184)
𝑚2 = 𝑐15 𝐶𝑃
2
𝑒𝑥𝑝(−0.1 𝐹
𝑛
−2
)
= −0.241564261
where 𝑐15 = −1.69385 when L3/∇ < 512 (here L3/∇ =
54.8937)
Additional Resistance due to presence of a Bulbous Bow (𝑅𝐵) is taken as 0 due to
the lack of a Bulbous Bow.
Additional Pressure Resistance due to the immersed Transom (𝑅𝑇𝑅) is also taken as
0 due to lack of immersion in Transom Area.
Model-Ship Correlation Resistance (𝑹𝑨):
𝑅𝐴 =
1
2
 𝑉2
𝑆 𝐶𝐴
= 26.76533355 𝑘𝑁
where,

45. Correlation Allowance Coefficient
𝐶𝐴 = 0.006 (𝐿 + 100)−0.16
− 0.00205 + 0.003√𝐿/7.5 𝐶𝐵
4
𝑐2(0.04 − 𝑐4)
= 0.000593028
where 𝑐4 = 0.04 when TF/L>0.04 (here TF/L=
0.0971)
Total Resistance of a Ship (Rtotal):
Rtotal = RF(1 + k1) + RAPP + RW + RB + RTR + RA
= 538.1146 kN
Effective Power (𝐏𝐄):
PE = Rtotal ∗ V
= 3598.48 kW
Assuming QPC = 0.6
Brake Power (𝐏𝐁):
PB = PE/QPC
= 5997.467 kW
2.6 PRELIMINARY VOLUME CHECK
Volume Available under the Deck:
VUD = 7350.786 m3
Required Volume under the Deck:
VRV = VFW + VDO + VLO + VSludge + VC + VM + VB
Volume of Fresh Water:

46. VFW = (200L)No. of Crew × No. of Day
where,
Number of Days = 15
Number of Crew = 30
Thus, Total Volume of Fresh Water:
VFW = 90 m3
Volume of Diesel Oil:
VDO = Fuel Consumption ∗ Time of Operation
where,
Fuel Consumption at Full Load (in L/hr) = 3335.6 L/hr
For Range = 710 nm at Service Speed = 13 Knots,
Time of Operation = 54.61 hrs
Thus,
VDO = 182.175m3
Volume of Lube Oil:
VLO = 3% of VDO
= 5.4652 m3
Volume of Sludge:
VSludge = 100 m3
Volume of Cargo (Mud/Cement):
Both Mud and Cement are of 400 m3
in Capacity.
VC = 800 m3

47. Volume of Machinery Room:
With respect to Volume Occupied by ABB Azimuth Thruster DZ1100-R2000 (including its
Auxiliary Machineries) and Caterpillar Diesel Generator C175-20,
Volume of Machinery Room is taken as:
VM = 2210 m3
Volume of Ballast Tank:
Ideally, Weight of Ballast Tank is taken equal to the Weight of Payload.
WB = Payload = 1450 tonnes
VB = 1450 m3
Thus, Required Volume under the Deck:
VRV = 5768.039679 m3
From the fact that VUD > VRV, we can conclude that the Current Dimensions satisfies needs
for necessary spaces within the Hull.

48. Chapter - 3
Hull Geometry

49. 3.1 OFFSET GENERATION
This section deals with exploring Hull Geometry - from Modelling of the Hull to
generation of the Faired Offsets and Drafting of Lines Plan. The Offsets obtained will
used in the next sections i.e., Bonjean Curves and Hydrostatic Calculations.
The steps for generating Faired Offsets is listed below:
Step 1: Prepare a Preliminary General Arrangement for the Vessel
Preliminary General Arrangement
Preliminary General Arrangement is designed based on General Arrangement of
Parent Ships as well as similar vessels available. This General Arrangement is
prepared in such a manner that it contains all the Necessary design aspects as per
referenced from the Various Sample GA’s, while also fulfilling the needs of the Owner
and being faithful to the Design Dimensions determined in the previous chapter.

50. Step 2: Obtain a Base 3D Model
Orca 3D’s Ship Hull Assist Interface
The above mentioned Preliminary General Arrangement is imported onto Rhinoceros
Program (here Rhino 7 is used). Using the Orca 3D extension within the Rhino
program, we can easily obtain a base model. With the help of Ship Hull Assistant within
the Orca 3D, a base model of a Hull can be obtained by inputting the detailed
dimension onto its interface and manipulating the model in a primal manner, as
represented in the image given below.

51. Base 3D Model obtained from Orca 3D
Step 3: Manipulating the 3D model
The 3D model is then manipulated to fit the imported Preliminary General Arrangement
using control points. Parallel Middle Body, Transom and other Structural Aspects are
also manipulated to fit the desired design. For more detailed oriented transformation,
the Rhino file (.3dm file) is imported into Maxsurf Modeler.
Maxsurf’s Parametric Transformation Function

52. Using its Parametric Transformation Function, the Model can be transformed on the
basis of Displacement, Block Coefficient, Prismatic Coefficient etc. After all the needed
transformation, the Final 3D Model is obtained.
The Final 3D Model
Step 4: Obtain Offset from the 3D Model
Process for obtaining Offset values, starting with defining Design Gird. While defining
Design Grid, we define the Design Station Spacing (=3.4 m), Waterline Spacing (=1
m) and Buttock Spacing (5 m & 7.5 m).
Defining Waterlines Defining Stations

53. Defining Buttocks
Next, Use Calculate Offsets Function under the Data tab of the Maxsurf Modeler.
Then, under the Window tab, select Offsets to obtain Offset tables of each Station.
Culminating them all, we obtain the required Offset Table.
Offset Window of Maxsurf Modeler
Step 5: Fairing the Offsets

54. From the above prepared Offsets, Lines Plan is drawing in AutoCAD. These lines are
made smooth and continuous i.e, Faired. Any and all modifications made during the
fairing process are also implimented onto the Offset Table.
Faired Lines Plan from AutoCAD is given below:
Body Plan
Half-Breadth Plan
Profile

55. Offset table obtained after the fairing process is given below:
WL
/ST
N 0.5 1 1.5 2 3 4 5 6 7
7.2
785
7
8 9
9.7
857
24
0
0 0 0 0 0 0
8.5
713
56
10.
443
91
10.
895
55
10.
952
12
11.
055
48
11.
184
29
11.
282
13
0.5
0 0 0 0 0 0
10.
574
49
11.
403
58
11.
663
84
11.
699
08
11.
780
58
11.
885
74
11.
966
45
1
0 0 0 0 0
10.
212
7
11.
747
37
12.
177
77
12.
319
88
12.
346
08
12.
411
14
12.
495
34
12.
560
87
1.5
0 0 0 0
8.3
853
55
11.
922
96
12.
570
04
12.
790
5
12.
875
16
12.
895
57
12.
946
28
13.
012
91
13.
065
35
2
0 0 0 0
11.
868
59
12.
837
6
13.
167
22
13.
276
78
13.
335
66
13.
351
25
13.
390
15
13.
442
35
13.
483
68
3
0 0
11.
634
35
12.
757
01
13.
567
29
13.
858
01
13.
951
5
13.
987
19
14.
019
52
14.
028
2
14.
050
18
14.
080
67
14.
104
9
4
10.
158
73
12.
699
84
13.
478
63
13.
874
91
14.
251
28
14.
376
8
14.
405
08
14.
421
98
14.
438
02
14.
442
37
14.
453
59
14.
469
36
14.
481
96
4.9
616
61
12.
426
84
13.
524
33
14.
011
19
14.
284
65
14.
539
86
14.
607
7
14.
616
71
14.
623
17
14.
629
35
14.
631
04
14.
635
47
14.
641
77
14.
646
86
6
12.
959
61
13.
814
79
14.
221
76
14.
453
31
14.
662
04
14.
707
1
14.
708
89
14.
710
01
14.
711
08
14.
711
38
14.
712
17
14.
713
34
14.
714
31
7
13.
079
39
13.
884
85
14.
273
97
14.
495
72
14.
693
4
14.
733
25
14.
733
63
14.
733
62
14.
733
61
14.
733
61
14.
733
61
14.
733
63
14.
733
64
8
13.
084
42
13.
887
83
14.
276
32
14.
497
69
14.
694
96
14.
734
62
14.
735
14.
735
14.
735
14.
735
14.
735
14.
735
14.
735
9
13.
084
42
13.
887
83
14.
276
32
14.
497
69
14.
694
96
14.
734
62
14.
735
14.
735
14.
735
14.
735
14.
735
14.
735
14.
735
10
13.
084
42
13.
887
92
14.
276
34
14.
497
5
14.
694
9
14.
734
71
14.
735
14.
735
14.
735
14.
735
14.
735
14.
735
14.
735
11
13.
061
13.
865
56
14.
255
27
14.
477
9
14.
677
64
14.
719
6
14.
722
13
14.
724
44
14.
726
88
14.
727
58
14.
729
35
14.
731
75
14.
733
58
12
12.
903
25
13.
712
95
14.
108
56
14.
337
5
14.
550
36
14.
605
12
14.
620
26
14.
637
62
14.
657
45
14.
663
36
14.
679
07
14.
701
65
14.
720
03

56. 13
12.
479
33
13.
300
21
13.
709
43
13.
953
25
14.
197
83
14.
284
13
14.
330
15
14.
386
09
14.
453
96
14.
474
51
14.
529
8
14.
611
08
14.
678
76
14
11.
643
83
12.
478
55
12.
911
03
13.
182
04
13.
486
65
13.
633
48
13.
735
92
13.
858
45
14.
010
26
14.
057
06
14.
184
33
14.
373
7
14.
533
4
15
10.
245
28
11.
084
81
11.
547
82
11.
858
97
12.
258
12.
503
91
12.
695
58
12.
909
97
13.
175
35
13.
258
57
13.
487
34
13.
829
03
14.
118
23
16
8.2
229
77
9.0
580
55
9.5
523
62
9.9
074
02
10.
417
46
10.
788
56
11.
097
85
11.
419
99
11.
809
95
11.
936
08
12.
292
34
12.
827
7
13.
280
98
17
5.7
612
42
6.6
124
85
7.1
432
2
7.5
361
61
8.1
386
18
8.6
181
41
9.0
397
39
9.4
562
35
9.9
405
55
10.
098
36
10.
573
76
11.
324
06
11.
962
41
18
3.2
332
96
4.0
672
66
4.6
155
18
5.0
312
19
5.6
785
95
6.2
186
23
6.7
095
58
7.1
852
89
7.6
996
32
7.8
611
55
8.3
545
87
9.2
417
45
10.
016
27
18.
494
25
2.0
773
34
2.8
520
11
3.3
759
45
3.7
862
4
4.4
333
18
4.9
786
97
5.4
817
22
5.9
719
48
6.4
854
82
6.6
420
98
7.1
068
78
7.9
712
99
8.7
426
67
19
1.0
144
67
1.6
719
02
2.1
352
25
2.5
075
91
3.1
208
07
3.6
505
89
4.1
481
47
4.6
380
81
5.1
451
2
5.2
958
92
5.7
295
45
6.5
050
86
7.1
982
44
19.
5
0.2
863
38
0.6
889
84
0.9
766
25
1.2
468
81
1.7
384
85
2.2
059
34
2.6
708
83
3.1
419
51
3.6
318
64
3.7
762
5
4.1
829
37
4.8
383
71
5.4
097
23
20
0.3
564
94
0.6
725
15
1.2
340
54
1.9
103
76
2.4
407
17

57. 3.2 BONJEAN CALCULATIONS
In this section, the Sectional Area and Moment of each station up to each waterline is
calculated. This enables the calculation of Displacement, LCB and VCB for any
waterline in both even keel and trimmed condition. The calculations are done by
integrating the offsets for particular station and waterline using Simpson’s formulae.
The results are in the tables given below:

58. Bonjean Area Table
STN/WL 0.5 1 1.5 2 3 4 5 6 7 7.278571 8 9 9.785724
0 0 0 0 0 0 0 6.781477 20.25793 35.36133 39.62162 50.73546 66.3033 78.65999
0.5 0 0 0 0 0 0 8.539102 23.99011 40.20366 44.75943 56.61666 73.18308 86.30195
1 0 0 0 0 0 8.161329 23.66221 40.53864 57.62542 62.43529 74.93769 92.37222 106.1533
1.5 0 0 0 0 6.435319 20.98837 38.4707 55.9854 74.22072 79.24601 92.29615 110.4676 124.8108
2 0 0 0 0 9.579626 26.94855 45.22653 63.71408 82.37787 87.58181 101.0862 119.869 134.6785
3 0 0 4.685204 10.3237 28.81132 48.06965 67.5217 87.10687 106.6843 112.1536 126.3332 146.0248 161.527
4 0 8.1033 17.36857 26.88413 46.58032 66.67065 86.78997 106.9996 127.1711 132.8028 147.3952 167.6413 183.5648
4.961661 0 9.118528 18.79158 28.6844 48.87982 69.30856 89.75392 110.2341 130.6987 136.4044 151.184 171.6781 187.787
6 0 9.397188 19.23613 29.26673 49.6659 70.24406 90.82558 111.4286 132.0136 137.751 152.6099 173.2077 189.3931
7 0 9.461772 19.34165 29.40628 49.85696 70.47414 91.09163 111.7281 132.3458 138.0919 152.9728 173.5999 189.8071
8 0 9.464493 19.34615 29.41235 49.86549 70.48468 91.1041 111.7425 132.3621 138.1087 152.9911 173.6201 189.8288
9 0 9.464493 19.34615 29.41235 49.86549 70.48468 91.1041 111.7425 132.3621 138.1087 152.9911 173.6201 189.8288
10 0 9.464533 19.34624 29.41238 49.86517 70.48455 91.10392 111.7424 132.3619 138.1086 152.9909 173.6199 189.8286
11 0 9.448495 19.31498 29.36689 49.79406 70.39064 90.99054 111.6125 132.219 137.9627 152.8384 173.4612 189.6673
12 0 9.339825 19.10151 29.05292 49.2927 69.72015 90.16854 110.6579 131.155 136.8726 151.6905 172.257 188.4392
13 0 9.046851 18.52424 28.20146 47.92534 67.88152 87.90211 108.0106 128.1887 133.8298 148.477 168.8756 184.9852
14 0 8.466298 17.37612 26.50406 45.18986 64.19305 83.34289 102.663 122.1602 127.6333 141.8952 161.8859 177.785
15 0 7.487496 15.43088 23.61901 40.51755 57.86995 75.50319 93.42817 111.6749 116.8295 130.3362 149.4577 164.8289
16 0 6.068239 12.60176 19.40905 33.65063 48.51309 63.82975 79.59307 95.83737 100.4678 112.7032 130.2872 144.6472
17 0 4.349501 9.182694 14.31786 25.30085 37.04862 49.40461 62.35751 75.91372 79.82131 90.26073 105.5892 118.3969
18 0 2.571863 5.627505 9.00266 16.51154 24.85263 33.90078 43.6323 54.0376 57.07196 65.26091 77.57834 88.17038
18.5 0 1.739897 3.934309 6.439705 12.20737 18.80554 26.12795 34.14838 42.86028 45.42016 52.36339 62.91812 72.11092
19 0 0.951552 2.29537 3.919645 7.868986 12.61897 18.0756 24.23022 31.07021 33.1062 38.67405 47.23829 54.77522
19.5 0 0.348071 0.937743 1.711289 3.808401 6.567775 9.983849 14.0491 18.79011 20.23469 24.25408 30.56899 36.20552
20 0 0 0 0 0 0 0 0 0.249546 0.450202 1.413019 3.61412 6.007252

59. Bonjean Moment Table
STN/WL 0.5 1 1.5 2 3 4 5 6 7 7.278571 8 9 9.785724
0 0 0 0 0 0 0 22.06165 74.09893 142.8563 164.1475 223.5831 316.2222 397.4725
0.5 0 0 0 0 0 0 27.76175 87.31584 161.1088 183.8764 247.2864 345.8652 432.1259
1 0 0 0 0 0 20.82929 69.7824 134.7918 212.6149 236.6524 303.5117 407.2541 497.8681
1.5 0 0 0 0 11.94661 47.89049 103.0127 170.6635 253.2624 278.3765 348.1642 456.2897 550.5991
2 0 0 0 0 17.73361 60.36662 117.9692 189.1894 274.0598 300.0666 372.2831 484.0447 581.4193
3 0 0 4.337088 11.8817 44.30123 91.50786 152.8158 228.1803 317.3208 344.6537 420.4799 537.6474 639.5761
4 0 1.469958 12.42912 21.28579 55.84459 105.0014 168.4819 246.1674 338.0934 366.2377 444.2714 564.7368 669.4341
4.961661 0 1.618149 13.28349 22.22441 57.6157 107.6407 172.0883 250.8853 344.0603 372.5749 451.6089 573.5491 679.4658
6 0 1.661968 13.56837 22.57713 58.31493 108.7124 173.5773 252.8594 346.5677 375.2402 454.6982 577.2556 683.6748
7 0 1.672255 13.63671 22.66387 58.48964 108.984 173.9599 253.373 347.2272 375.9434 455.5193 578.2503 684.8128
8 0 1.672689 13.63964 22.66774 58.49775 108.997 173.9789 253.3995 347.2625 375.9814 455.5648 578.3073 684.8796
9 0 1.672689 13.63964 22.66774 58.49775 108.997 173.9789 253.3995 347.2625 375.9814 455.5648 578.3073 684.8796
10 0 1.672698 13.63971 22.66772 58.49721 108.9968 173.9788 253.3994 347.2624 375.9813 455.5646 578.3072 684.8795
11 0 1.669913 13.61802 22.63423 58.41899 108.8631 173.7836 253.1412 346.9449 375.6486 455.1968 577.9025 684.458
12 0 1.651001 13.46949 22.40076 57.85858 107.8894 172.3338 251.1821 344.4892 373.0627 452.3022 574.6748 681.0733
13 0 1.599958 13.06742 21.76563 56.32307 105.2018 168.3013 245.6868 337.5455 365.7368 444.0649 565.4433 671.3676
14 0 1.498644 12.26677 20.49575 53.24095 99.79009 160.1509 234.5084 323.2732 350.6254 426.8964 545.856 650.4007
15 0 1.327452 10.90799 18.32876 47.95277 90.46641 146.0555 215.0529 298.1334 323.8942 396.1309 509.9315 611.0117
16 0 1.078991 8.929801 15.15621 40.13841 76.56254 124.8622 185.5487 259.5268 282.6684 348.1121 452.7808 547.2204
17 0 0.778542 6.540747 11.32075 30.60897 59.4088 98.39387 148.2637 210.0264 229.5556 285.4006 376.6662 460.9092
18 0 0.467103 4.052135 7.298162 20.50902 40.97099 69.53566 107.0156 154.4338 169.599 213.4103 286.7715 356.4533
18.5 0 0.320298 2.860069 5.331392 15.49131 31.68917 54.81144 85.7136 125.4151 138.2091 175.3578 238.229 298.7106
19 0 0.179944 1.698288 3.364689 10.33766 22.00665 39.25177 62.96861 94.15481 104.3307 134.1231 185.1437 234.734
19.5 0 0.069133 0.712793 1.546074 5.256432 12.05798 22.85227 38.5484 60.15247 67.37268 88.88365 126.5109 163.5999
20 0 0 0 0 0 0 0 0 0 0 0 0 0

60. Bonjean Curves

61. 3.3 HYDROSTATIC CALCULATIONS
It is mandatory in the design of a ship to calculate and plot as curves a number of
hydrostatic properties of the vessel’s form at a series of drafts. Throughout its life a
ship changes its weight, trim & freeboard. Its condition at any state of circumstances
can be found from hydrostatic curves. Hydrostatic particulars corresponding to
different waterlines are calculated. The calculations are done by integrating the offsets
(Half Ordinates, Sectional Areas and Moments) by using Simpson’s Rules for Numeric
Integration.
The results are given in table below:

62. Hydrostatics Table
0.5 1 1.5 2 3 4 5 6 7 7.278571429 8 9 9.785724367
AWP 333.60 378.02 487.86 510.56 607.00 668.75 730.63 748.16 763.02 768.13 781.28 801.96 819.55
Mmid 1789.58 1892.93 1065.90 1047.66 -670.76 -1801.38 -3131.31 -3138.76 -2924.37 -2820.55 -2555.25 -2124.86 -1753.46
LCF (FROM
MIDSHIP) 5.36 5.01 2.18 2.05 -1.11 -2.69 -4.29 -4.20 -3.83 -3.67 -3.27 -2.65 -2.14
IL 75588.13 91117.19 138739.68 148696.09 208137.88 252068.83 303789.74 315981.25 325539.91 329025.29 337566.66 350796.27 362008.94
IT 13246.41 18067.86 23953.84 26727.83 32088.94 36373.99 39745.22 41434.51 42700.13 43062.40 44111.07 45916.04 47628.66
IF 65988.07 81638.48 136410.87 146546.34 207396.65 247216.56 290369.73 302813.17 314331.84 318668.23 329209.44 345166.25 358257.36
▼ 0.00 125.22 276.71 439.15 834.01 1280.82 1770.36 2288.04 2816.82 2965.68 3354.90 3904.43 4345.36
▲ 0.00 129.12 285.33 452.83 859.99 1320.72 1825.51 2359.31 2904.56 3058.06 3459.40 4026.06 4480.72
MT 0.00 22.37 200.56 359.31 1054.69 2152.45 3697.33 5690.60 8097.47 8841.45 10923.00 14193.48 17092.94
ML 0.00 642.53 1637.42 2274.17 2322.92 1463.01 -257.34 -2450.89 -4610.72 -5183.98 -6604.33 -8386.32 -9609.37
BML - 651.95 492.97 333.70 248.67 193.01 164.02 132.35 111.59 107.45 98.13 88.40 82.45
BMT - 144.29 86.57 60.86 38.48 28.40 22.45 18.11 15.16 14.52 13.15 11.76 10.96
KB - 0.18 0.72 0.82 1.26 1.68 2.09 2.49 2.87 2.98 3.26 3.64 3.93
KMT - 144.46 87.29 61.68 39.74 30.08 24.54 20.60 18.03 17.50 16.40 15.40 14.89
KML - 652.12 493.69 334.52 249.94 194.69 166.11 134.83 114.47 110.43 101.38 92.04 86.38
TPC 3.42 3.87 5.00 5.23 6.22 6.85 7.49 7.67 7.82 7.87 8.01 8.22 8.40
LCB - 5.13 5.92 5.18 2.79 1.14 -0.15 -1.07 -1.64 -1.75 -1.97 -2.15 -2.21
MCT1cm - 26.88 40.83 43.86 52.37 58.14 63.73 66.46 68.99 69.94 72.26 75.76 78.63
T 0.35 0.70 1.05 1.40 2.10 2.80 3.50 4.20 4.90 5.10 5.60 6.30 6.85
CW 0.41 0.43 0.50 0.51 0.51 0.52 0.53 0.54 0.55 0.55 0.56 0.58 0.59
CB 0.00 0.21 0.27 0.31 0.33 0.35 0.37 0.39 0.42 0.42 0.43 0.45 0.46
CM - - - - - - - - - - - - -
CP - - - - - - - - - - - - -
Hydrostatics Curves