This document provides an overview of various departments involved in ship design and construction. It discusses the forward design group, electrical and weapons department, outfit department, and structure department. Key points include how ships are launched, stability calculations, damage control assessments, electrical and navigation systems onboard, and outfitting elements like insulation, ladders, anchors, and ventilation. Calculations are performed to predict ship behavior during launch and to ensure stability under various loading conditions.
2. Index
1. Forward Design Group
2. Electrical & Weapons
3. Outfit Department
4. Structure Department
3. Forward Design Group
Launching
The ship is built section by section and gradually pushed from the building hall into the open.
A dry dock can be used and flooded up when the ship is sufficiently far advanced.
Occasionally, slipways are partially or wholly below high water level and the site is kept dry
by doors which, on launch day are opened to let the water in and provide some buoyancy to
the hull. More often, the hull is constructed wholly above water and slid into the water when
ready.
Usually, the ship slides stern first into the water because this part of the ship is more buoyant.
Less often, the ship is slip or tipped sideways into the water and the considerations are then
rather different.
In a well ordered, stern first launch, sliding ways are built around the ship, and shortly before
the launch the gap separating them from the fixed ground ways is filled by a layer of grease
to which the weight of the ship is transferred from the building blocks.
After it begins to enter the water, the buoyancy builds up at the stern until it reaches the value
sufficient to pivot the entire ship about the fore puppet (i.e. forward end of the launching
cradle). The ship continues down the way until it is floating freely having side away from, or
dropped off the end of, the ways.
Conditions that might go wrong in this procedure, they are, the grease might be too slippery
or not slippery enough. It might be squeezed out by the pressure. Instead of stern lifting, the
ship might tip the wrong way about the end of the ground ways and plunge.
Calculations are carried out before arranging the launch to investigate each of these problems.
The calculations predict the behaviour of the ship during launch, to enable a suitable high tide
to be selected and to arrange the ship and slip to be in proper and safe condition.
Launching Curves
A set of six curves is prepared to predict the behaviour of the ship during launch. They are
curves, plotted against distance of travel down the slip, of, Weight (W), Buoyancy, Moment
of weight about fore puppet, Moment of buoyancy about fore puppet, Moment of end about
after end of ground ways, Moment of buoyancy about after end of ground ways.
Conventionally, the Moment of end about after end of ground ways is drawn positive when
anti-clockwise and Moment of buoyancy about after end of ground ways is drawn positive
when clockwise.
4. The important features of these curves are as follows:-
a) At the point at which the moment of buoyancy about the fore poppet equals the
moment of weight about the fore poppet , the stern lifts
b) The difference between the weight and the buoyancy curves at the position of stern
lift, is the maximum force on fore poppet.
c) The curve of moment of buoyancy about the after end of the ways must lie wholly
above the curve of moment of the weight, the least distance between the two curves
gives the moment of tipping about the aft end.
d) Crossing of the weight and buoyancy curves before the after end of the ways,
indicates that the fore poppet will not tip at the end of ways.
Docking and Undocking
The ship is constructed on the slipway and it rests on various keel blocks, bilge blocks and
side blocks. Slipway is a kind of ramp on the shore by which ship or boats can be launched
into the water. This is a one time job. This docking plan is made at the initial stage and is a
one time job.
The different blocks are -
Keel blocks on which the keel plate of the ship rests, is made of four C-channels.
Bilge blocks, which support the curve of the hull, are cylindrical.
Along the side of the keel blocks are the side blocks.
5. Fore Poppet and Aft poppet
Structures built under the stem and stern of the ship on the slipway form the fore poppet and
aft poppet respectively. These hinder the dislocation of the ship’s rear as well as front when it
is on the slipway.
Dry Docking ofthe ship
The ship is dry-docked for carrying out the remaining construction of the ship.
The ship is brought into the dry dock and then aligned with the already placed keel
blocks and bilge blocks.
The water is then slowly pumped out of the dry dock and the ship finally rests on the
keel blocks and the bilge blocks.
The ship is also additionally supported by wooden shores at the bottom and sides.
That help the ship in keeping still during her docking and undocking.
The docking plan both at the slipway and the dry dock shows the strengthened areas on the
hull for supporting the vessel with minimum stress. The arrangement ensures to support each
portion of ship and prevent it from bending due to its own bending.
Inclining Experiment
An inclining experiment is a test performed on a ship to determine its stability, lightship
weight and coordinates of its centre of gravity. This experiment involves shifting of weight
on the ship and noting the heeling angle by use of pendulums installed in the ship at different
locations.
Procedure:
Different weights are taken and placed at the predefined aft, forward and midship
marks.
The distance of the ship is also recorded.
The locations of pendulums are decided.
The draft marks at each shift are also recorded on both sides.
Then by shifting weights in different order and using the net deflection formula, mean
deflection per moment is calculated.
Intact Stability
The vessel is in normal operational configuration. The hull is not breached in any
compartment. The vessel will be expected to meet various stability criteria such as GMt
(metacentric height), area under the GZ (righting lever) curve, range of stability, trim, etc.
6. The intact conditions include-
Light Ship - The vessel is complete and ready for service in every respect, including
permanent ballast, spare parts, lubricating oil, and working stores but is without fuel,
cargo, drinking or washing water, officers, crew, passengers, their effects, temporary
ballast or any other variable load.
Deep sea going condition-Along with all the Lightship loads, the vessel has all
systems charged meaning that all fresh water, cooling, lubricating, hydraulic and fuel
service header tanks, piping and equipment systems are filled with their normal
operating fluids. Crew and effects are at their normal values. Consumables
(provisions, potable water and fuel) are at 100% capacity. Ammunition and/or cargo
is at maximum capacity. The vessel is at its limiting draft or legal load line.
Light Harbour Condition-Along with all the Lightship loads, the vessel has all
systems charged meaning that all fresh water, cooling, lubricating, hydraulic and fuel
service header tanks, piping and equipment systems are filled with their normal
operating fluids. Crew and effects are at their normal values. Consumables
(provisions, potable water and fuel) are at 10% full load. Ammunition and/or cargo is
at 100% capacity.
The stability calculations are also done at various intermediate loading conditions, and finally
intact stability with growth margin is also calculated.
Growth Margin - Additional margin added in the ship weight calculation to cover for later
weight increases. This is because the ship gets heavier as it ages due to conversions,
modifications, painting etc. The modifications occur due to the improvisations made in the
successive ships of the same class. Without these considerations, the ship can later end with
stability problems.
Damage Stability
The vessel in the assessed "Worst Intact Condition" is analytically damaged by opening
various combinations of watertight compartments to the sea. As per the Naval Engineering
Standards (NES)-109, the ship can be flooded maximum without sinking till 15% of its
length or 21m whichever is more.
Based on these standards, different sets of compartments are flooded and the stability
calculations carried out, and the corresponding GZ curves drawn and metacentric heights
calculated.
Heeling Trials
Heeling trials are carried out to prove that the ship and the equipment within it continue to
function when the vessel is held at a steady angle of heel. For instance, pumps may fail to
maintain to suction, bearings of electric motor may become overloaded, boats may not be
able to be lowered by the davits clear of the ship, etc.
7. Electrical & Weapons Department
There are around 600 compartments in the ship which are needed to be well equipped with
every required electrical system. There are around 20-30 systems in Weapon and 60-70
electrical system in the ship. Statement of Technical Requirement or SOTR is obtained from
the Navy for each of these systems.
Steps to decide which company to give contractto for ElectricalSystems:
Step 1 - Reading of Statement of Technical Requirement (SOTR)
The technical requirements of different electrical systems are provided by the client.
Step 2 - Preparing Technical Specification of Procurement (TSP)
This is prepared by the company responsible for building the ship.
Step 3 - Deciding the quantity of different systems required on the basis of Budged
Quotation.
Step 4 - Purchase Requisition is done using the SAP software.
Step 5 - Purchase Requisition and Technical Specifications Procurement is then sent to the
commercial department who then put an online tender for the different systems required.
Step 6 - The companies then approach with their Techno-Commercial offers to the Ship
Building Industry within 15 days of passing the tender. The offers are passed to the
Commercial department as well as the Design Department.
Step 7 - Technical Negotiation Committee (TNC) is held with the preferred companies who
offered the Techno-Commercial offers. The committee includes people from the Navy;
Design, Planning and Commercial department of the Industry and the companies with their
offers. After the meeting, finally clearance is given to a particular company to deliver the
order in specified time duration.
Lighting System in Ships:
Automatic Emergency Lights
Automatic Emergency Lanterns are the battery backed lighting devices that are fitted at the
exit doors and switches on automatically when the ship experiences a Power Outage.
8. Red Shade Fluorescent Lights
A fluorescent lamp is a low pressure mercury vapour gas discharge lamp that uses
fluorescence to produce visible light. An electric current in the gas excites mercury vapour
which produces short wave ultraviolet light that then causes a phosphor coating on the inside
of the lamp to glow.
In a Naval Ship, these lights are used so that the movements inside the ships are not detected
from outside and helps people inside the ship to move around.
Degaussing System in Ships
Degaussing is the process of decreasing or eliminating a remnant magnetic field. Due to
magnetic hysteresis, it is generally not possible to reduce a magnetic field completely to zero,
so degaussing typically induces a very small "known" field referred to as bias. Degaussing
was originally applied to reduce ships' magnetic signatures during the Second World War.
The degaussing system is installed aboard ship to reduce the ship's effect on the Earth's
magnetic field. In order to accomplish this, the change in the Earth's field about the ship's hull
is "cancelled" by controlling the electric current flowing through degaussing coils wound in
specific locations within the hull. This, in turn, reduces the possibility of detection by these
magnetic sensitive ordnance or devices.
The details of the magnetic field are fed in the Magnetometer. The System first collect data
through sensors and generates magnetic field of an area in the sea in the form of digital
signals.
Magnetic field of the ship and earth is neutralized in such a way that the sea mines won’t
detect it. The parts of the ship with more ferrous materials are wounded with more number of
coils.
EmergencySupply System
Fire pumps
A fire pump is a part of a fire sprinkler system's water supply and powered by electric, diesel
or steam. The pump intake is either connected to the public underground water supply piping,
or a static water source. It is used in case of any Fire related emergency.
Steering Gear
A Steering Gear is the equipment provided on ships to turn the ship to left (Port side) or to
right (Starboard side) while in motion during sailing. The Steering Gear works only when the
ship is in motion and, does not work when the ship is stationary. All the ships are to be
provided with, an efficient main steering gear, an auxiliary steering gear and, except for very
small ships, the main steering gear should be power operated.
9. Salvage System
Salvage system is used for recovering a ship, its cargo, or other property after a shipwreck or
other maritime casualty. Salvage may encompass towing, re-floating a sunken or grounded
vessel, or patching or repairing a ship.
NavigationSystems:
1. Eco- Sounder- It is used to measure the depth of the sea.
2. Electro- Magnetic Log- It is used for measuring the speed of the speed.
3. Differential Global Positioning System (DGPS) - Differential Global Positioning
System (DGPS) is an enhancement to Global Positioning System that provides
improved location accuracy.
4. Magnetic Compass- It is used for measuring the course and heading of the ship.
5. Automatic Identification System (AIS) - It is an automatic tracking system used on
ships and by vessel traffic services (VTS) for identifying and locating vessels by
electronically exchanging data with other nearby ships.
6. Voyage Data Recorder (VDR) - Records the data of ship’s journey and is saved at the
time of damage/ sinking to figure the cause of accident.
7. Radar
8. Electronic Chart Display Information System (ECDIS)
Communication systems:
Internal
1. MBSRE - Main Broadcast Sound Reproduction Equipment is meant for
recreating sound waves and for general music and announcements, etc.
2. Auto-telephone - This is used for communicating mainly in emergency
conditions.
3. Sound or self-powered telephone - This allows the users to communicate with
each other without the use of any external power supply.
External
It creates a communication channel between a source transmitter and a receiver at
different locations on Earth, through satellite communication, using frequencies of
various ranges.
10. Outfit Department
1. Guard rail on weatherdeck arrangement
Guard rails are provided on the deck to provide support to the person moving on the
deck. This is necessary because the ship keeps on surging, swaying, heaving, rolling,
pitching and yawing continuously.
2. Guard rail arrangement around hatches
Guard rails are provided around hatches to provide support to the person climbing on
the ladder. The ladders can be both vertical as well as sloping.
3. Awning arrangementfor weatherdeck
Tents are arranged for ceremonial purposes on the weather deck when some
dignitaries have come to visit. These tents protect the people from the sun.
4. Key plan for bollards and fair leads
The rope is passed through the fair lead and then tied to the bollard. Since an angle is
created by the rope at the fair lead, the stress is distributed amongst the fair leads and
bollards. Also, the fair leads prevent the rope from being cut due to friction on the
deck. The rope should be able to withstand the tension while moving the ship. This
tension arises due to water resistance, air resistance and the velocity of the ship. A
rope of appropriate diameter must be chosen.
5. Access plan (doors, hatches, EES)
It gives the general arrangement of all the doors and hatches inside the ship.
EES – Emergency Escape Scuttle
6. Manhole key plan
It gives the general arrangement of all the manholes inside the ship.
7. Ladder keyplan
It gives the general arrangement of all the ladders inside the ship.
11. 8. Insulation/Lining plan
Types of insulation:
a. Thermal insulation – To stop heat from transferring from one compartment to
another.
b. Acoustic insulation – To stop the transfer of noise.
For eg. From the engine room to the adjacent rooms.
c. Fire insulation – To stop fire from spreading for some amount of time to the
adjacent compartments so that there is time to extinguish the fire.
9. Windows, bridge and L.S.O. arrangement
The captain of the ship navigates and maneuverers the ship from the bridge. He must
have a 360 degree view from there. Hence, windows are installed on all sides. These
windows are very strong and have 85% transparency. Heating coils are installed
inside these windows so that an ice layer is not formed on the window if the ship is to
travel through an icy region.
10.Brow ships (ALU) arrangementand details
For boarding from jetty to the ship.
11.Draught marks and boot topping line
Draught marks – Indicate the locations of the light ship waterline and the deep
waterline.
Boot topping line – The line which marks the area of the hull of ship up till which it
faces air water interface. This area is given an extra coat of paint to prevent corrosion
due to constant contact with water.
12.Cathodic Protection(Passive)
In the wet basin, sacrificial anodes are hung on both sides of the hull. These anodes
themselves get corroded but prevent the corrosion of the hull.
13.Anchor and Cable arrangement
Anchors are used to keep the ship stationary near the shore. The anchor is dropped
from the forecastle deck into the water and when it hits the sea bed it is dragged and
gets stuck. The anchor chain is wound around the capston.
12. 14.A/C and HE Ventilation
NBC filter – Nuclear Biological Chemical filter
Cooling of different compartments depends upon the heat load of the compartment
and human occupancy. 20% of the air comes from the Air Filtration Unit (ATU) and
80% comes from the Air Treatment Unit (ATU).
15.RAS arrangement
RAS – Replenishment at Sea
If the ship is running low on fuel, it can be refilled by going near another ship and
transferring the fuel through a pipe which is locked by a male female coupling
arrangement.
Injured men are provided with help by transporting them to another ship which is well
equipped with medical facilities. This is done by cable cars. Food and drinking water
is also replenished.
16.Life Raft/BuoyStowage KeyPlan and details
During an emergency, people are evacuated using life rafts.
17.Net Scrambling for Life Saving
In case someone falls into the water, a net is thrown at him. The person can then
climb the net and return to the deck safely.
18.Portable Davit arrangement and details
This system is used for the storage and launching of life rafts. They can be both
manually or electrically controlled.
19.Darkening Ship arrangement
To prevent the ship being spotted from a distance, only low wavelength red lights are
used inside the ship when enemies are nearby.
20.Ammunition Embarking/Transport Route
This is the route used for transporting ammunition while reloading. It can be
controlled both manually and automatically.
13. 21.Helo Securing Ring/Sunken Eye Plates arrangement
The helicopter lands on this securing ring. Hooks are provided to secure the
helicopter with ropes so that it does not slip. This ring bulges inside the deck, hence it
is called sunken eye plate.
22.SafetyNet around Helipad
Adequate safety precautions are taken around the helipad so that the helicopter lands
and takes off safely.
23.Flight Deck Marking
Marking are made on the deck so that they are visible from a distance while landing
the helicopter and it makes sure it lands in the correct place.
24.Helo Traversing system
The helicopter is traversed to the hanger using this system.
25.Hanger Shutter system
To protect the helicopter from the environment, it is parked inside the hanger using a
shutter system.
Some more systems:
Storm rail and support details
Flag staff arrangement and details
Ensign staff arrangement and details
Aerial and v/s rig
Towing arrangement forward and aft
Mooring and Berthing Plan
Reels Hawser and Cordage Details
How to check if a compartment below the waterline is flooded?
If the hatch is opened directly, it will open with great force due to the pressure of the air
trapped over the water which may lead to death. To prevent this, a small screw is provided
on the hatch which is to be opened before opening the hatch. This releases the excess
pressure. If a few water drops come out along with the air, it indicates that the compartment
is flooded.
14. Types of Propellers:
Water Jet Propellers
Fixed Pitch and Variable Pitch Propellers
Co-axial Propellers
Surface Piercing Propellers
Super Cavitating Propellers
Azimuthal Propellers
Controllable Pitch Propellers
Sails
Ores
Fire Point:
The fire point of a fuel is the temperature at which the vapour produced by that given fuel
will continue to burn for at least 5 seconds after ignition by an open flame.
At the flash point, a lower temperature, a substance will ignite briefly, but vapour may not be
produced at a rate to sustain the fire.
Flashpoint:
The flash point of a volatile material is the lowest temperature at which vapours of a fluid
will ignite. Measuring a flash point requires an ignition source. At the flash point, the
vapour may cease to burn when the ignition source is removed.
15. Structure Department
Structural drawings
Every block is prepared in the modelling shop, where every block constitutes of several units.
These units are fabricated individually. Hence it depends on two major factors that that how
big these units and blocks should be which are -
Fabrication
Crane capacity to lift the unit
Now the units are fabricated parallelly, so there is a naming given to every unit depicting
three specifications
1. Block No.
2. Port/starboard
3. Deck level
For port, it is 1 and for starboard, it is 2.
Unit Alignment
Now the units have been fabricated in the modeling shop, but the blocks have to be
constructed by putting the units together. Hence it should be taken cared properly that the
units are aligned properly when they are placed over each other in the slipway. For this not
happen, a rough margin of 300mm is provided in the construction of every unit because there
is always a possibility of making a little error in positioning of the units.
Key plan of a Bulkhead
In the structural drawing of a unit, the key plan of bulkhead is provided in the beginning
itself. The reason is we first make the shell plate then the bulkhead arrangement which is
going to be placed over there. And after that the stiffening arrangement, so for the
construction people it is easier to understand if key plan of bulkhead is provided in the 2nd
page of the structural drawing of the unit.
Shell expansion is done while making the drawing of shell plate because the hull curve is 3D
which is difficult to depict from the drawing , hence shell plate is flattened in 2D drawing and
hence the specifications of drawings are shown.
16. Slipway Preparation
In the slipway, the blocks are joined to form the hull, hence this construction is known as
slipway preparation, there is a proper way of making joining the blocks to prepare hull on the
slipway. We first start from the middle of the slipway and the joining of blocks take place
parallelly. This has an advantage. Suppose in one direction there arises a problem then the
work in other direction would be continued without delay. Hence all the welding and
stiffening would be provided simultaneously in both sides.
Assembly
All the units are fabricated, the plate cutting, nesting, etc. all have taken place and the unit is
ready. Now what happens is that the units are aligned to form blocks, this is assembly, as the
units are assembled to make blocks. This is prior to slipway preparation.
Fairing
The client sends the lines plan drawings which are faired by shipyards using whatever
software they use to fair them.