1. Bangladesh University of Engineering & Technology Department of Naval Architecture and Marine Engineering
NAME-118
Ship design & DRAWING I
LEVEL-1 , TERM-II
Contact Hr: 3 Credit: 1.50

2. General Arrangement Plan
Lesson 1

3. What is a General Arrangement Plan?

4. General Arrangement Plan
The general arrangement of a ship can be defined as the drawing which indicates the assignment of spaces for all the required functions and equipment, properly coordinated for location and access.

5. General Arrangement Plan
Four consecutive steps characterize general arrangement:
Allocation of main spaces
Setting individual space boundaries,
Choosing and locating equipment and furnishing within boundaries
Providing interrelated access

6. General Arrangement Plan
GA Plans are prepared and modified for the conceptual, preliminary, contract and working plan stages.
The data in the early stages comes from past experience and the degree of detail increases as the design progresses.

7. General Arrangement Plan
Design Spiral

8. General Arrangement Plan
Certain requirements must be met:
Watertight subdivision and integrity
Adequate stability
Structural integrity
Adequate provision for access

9. General Arrangement Plan
Contains
Side view: Elevation
Plan views of the most important decks: Main Deck, Under Deck, Bottom Deck, Poop Deck, Bridge Deck etc.
Cross-section

13. General Arrangement Plan
The views and sections display:
division into compartments (tanks, engine room, holds)
location of bulkheads
location and arrangement of superstructure
parts of the equipment (winches, loading gear, bow thruster, life boats)

14. Scale of GA
Scale is considered the ratio of the length in a drawing (or model) to the length of the real thing.
A length of 1 cm taken from a 1:100 general arrangement plan represents the actual length of
1 cm x 100 = 100 cm

15. Scale of GA
Small scale
Possible to draw several decks on one sheet of paper
Eases the work of lining up items that appear on two or more decks and helps to avoid inconsistencies

16. Scale of GA Ship Length Best Scale to Use Above 200 m 1:200 or Smaller
100 m ~ 200 m
1:200
30 m ~ 100 m
1:100
Below 30 m
1:50

17. Factors influencing the GA Plan
The main purpose of the ship
The designer’s ideas on how this purpose can best be achieved.
For cargo ships
carry as much cargo as possible
cost effectiveness
deliver in good condition
methods of loading and discharge that are speedy and economical.
For passenger ships
cabins, public rooms and the services provided to passengers will result in their comfort during the voyage

18. Factors influencing the GA Plan
For service ships
perform its service functions efficiently.
For warships
positioning of each of the combat systems so that all its components will function at near to their optimum capability and, if possible, will continue to do so after enemy attack.

19. General Arrangement Plan
Locate the main spaces and their boundaries within the ship hull and superstructures.
Cargo spaces
Machinery spaces
Crew, passenger and associated spaces
Tanks/holds
Miscellaneous

20. Basic data included in the GA:
Dimensions
Volumes of the holds
Tonnage
Deadweight
Engine power
Speed
Class
Class – registar, length of voyage, type of voyage, dangerous cargo….

21. Profile view of a Ship

22. Shipboard terminology
aft: toward the stern of a ship
stern: the rear of a ship (opposite of "bow")
bow (or stem): front of a ship (opposite of "stern")
abaft: at or toward the stern of a ship, or further back from a location
astern: toward the rear of a ship (opposite of "forward")
fore or forward: at or toward the front of a ship (opposite of “abaft")
port: the left side of the ship, facing forward (opposite of "starboard")
starboard: the right side of the ship, when facing forward (opposite of "port")

23. Shipboard terminology
amidships: near the middle part of a ship
athwartships: toward the sides of a ship
aboard: onto or within a ship, or in a group
inboard: attached inside the ship
on board: somewhere on board the ship
outboard: attached outside the ship
centerline: an imaginary, central line drawn from the bow to the stern

24. Shipboard terminology

25. Components of a Ship Upper Deck Or Main Deck Forecastle Tanktop
Peak Tank
Chain Locker
Collision Bulkheads
Engine Room
Double Bottom
Cofferdams
Superstructure

26. Upper deck or main deck the principal deck of a vessel
in some ships the highest deck of the hull
usually but not always the weather deck (that is open to the sky and exposed to the weather)

27. Forecastle foremost part of the upper deck
usually raised above the main deck

28. Cofferdam
A void or empty compartment is provided between the tanks to prevent two different liquids from mixing with each other. This space is known as cofferdam.
The space avoids intermixing of two different liquid when there is a leak from the boundary separating the two liquid.

29. Cofferdam Cofferdam dam may be provided:
Between fuel oil tanks, and lube oil and fresh water tanks in the engine room.
Between other different grade liquid tanks like diesel oil and fuel oil service tanks.
At fore and aft ends of the cargo holds/cargo tanks area.
Between cargo holds/cargo tanks and engine room.
In Oil Tankers, apart from the above mentioned locations, cofferdams are additionally fitted:
Between cargo space and machinery space.
Pump room also may be a part of cofferdam.

30. Cofferdam

31. Double Hull and Double Bottom
Two levels or layers of hulls – the outer layer and the inner layer.
The double hulls are an important requirement in ships, especially oil tankers.
If one layer is damaged due to accident, the second layer acts as a back-up and prevents ingress of seawater into the ship.
Ballast water is used to store in these empty spaces to increase draft for stability.
Double bottom means the bottom of the ship has two complete layers of watertight hull surface:
one outer layer forming the keel of the ship
a second inner bottom, sometimes called tank top

32. Double Bottom and Double Hull

33. Double Bottom and Double Hull

34. Double Bottom and Double Hull

35. Tanktop inside bottom of the vessel
the plating forming the inner bottom of a ship hull

36. e. Upper hold / Lower hold
spaces that contain the cargoes

37. Peak tank
Aft Peak Tank
after-most watertight tank on the main hull structure
normally used for the storage of fresh water or ballast
provides a degree of protection to all spaces forward of the aft peak bulkhead.
Fore Peak Tank
fore-most watertight tank
normally used for ballast purposes so that the ship can be provided with the proper trim especially on the ballast journey
watertight collision bulkhead is usually fitted
chain locker for storing the anchor chain is normally located inside the fore peak tank.

38. Peak tank

39. Chain locker
A storage space in the forward part of the ship, typically in front of the foremost collision bulkhead, that contains the anchor chain when the anchor is secured for sea.

40. Bulkheads
similar to internal walls dividing a building into separate rooms.
vertical partitions which divide the main hull into different compartments.
arranged either transversely or longitudinally in ships are known as transverse bulkheads and longitudinal bulkheads respectively.

41. Bulkheads Functions of bulkheads
In the event of a damage to the hull plating, watertight bulkheads limit the extend of flooding
Prevent spread of fire from one compartment to another.
Longitudinal bulkheads contribute to the longitudinal strength of the ship.
Divide the main hull of a ship into different compartments such as the aft peak tank, engine room, cargo holds, deep tanks, cofferdam space, and the fore peak tank.

42. Bulkheads

43. Bulkheads All ships must have the following bulkheads-
a collision or fore peak tank bulkhead
an aft peak tank bulkhead
a bulkhead at each end of the engine room

44. Collision bulkheads foremost major watertight bulkhead
in the event of a collision, damage to the cargo located aft of the collision bulkhead will be minimized.
fireproof

45. Collision bulkheads

46. Engine room = machinery space watertight compartment
houses the main and auxiliary machinery
on a large percentage of vessels engine room is located near the bottom, and at the aft

47. Superstructure the parts of the ship that project above her main deck
accommodation for the crew and passengers, messroom, galley, pantry, store, infirmary, wheelhouse
usually consists of several decks (poop deck, navigation deck etc.)

48. Oil Tanker
An oil tanker/petroleum tanker, is a merchant ship designed for the bulk transport of oil with specific gravities in the range of to 0.97 (diesel oil, crude oil etc)
Oil tankers generally have from 8 to 12 tanks. Each tank is usually split into one centerline tank and wing tanks port and starboard.
Tankers generally have cofferdams forward and aft of the cargo tanks, and sometimes between individual tanks.
A pump room houses all the pumps connected to a tanker's cargo lines.
Most new tankers are "double hulled“
All single-hulled tankers around the world will be phased out by 2026, in accordance with the International Convention for the Prevention of Pollution from Ships, 1973 (MARPOL).

49. SEA FORCE 300000 DWT Oil Tanker

50. Oil Tanker

51. Bulk Carriers
A bulk carrier, bulk freighter, or bulker is a merchant ship specially designed to transport unpackaged bulk cargo, such as grains, coal, ore, and cement in its cargo holds.
Today, bulkers make up 40% of the world's merchant fleets and range in size from single- hold mini-bulkers to mammoth ore ships able to carry 400,000 metric tons of deadweight (DWT).

52. SABRINA I 52000 DWT Bulk carrier (190 m X 32 m)
Bulk Carriers
SABRINA I DWT Bulk carrier (190 m X 32 m)

53. Bulk Carriers

54. Container Ships
A ship specially constructed and equipped to carry only containerized cargoes, in all available cargo spaces, either below or above deck.
Container ships are very fast, with speeds up to 30 knots.
They have carrying capacities from 1,000 up to 12,000 TEUs or more.
TEU (twenty-foot equivalent unit) is the size of the standard 20-foot container.
Various types of containers exist for the transportation of break bulk, liquid and refrigerated cargo.
Cargo-handling equipment is rarely fitted, since these ships travel between specially equipped terminals to ensure rapid loading and discharge.

55. MAERSK SEALAND 3500TEU Container Vessel (255 x 32.2 m)
Container Ships
MAERSK SEALAND 3500TEU Container Vessel (255 x 32.2 m)

56. Container Ships

57. Passenger Ships
A passenger ship is a merchant ship whose primary function is to carry passengers. Usually defined as a ship carrying more than 12 passengers 
Passenger ships include ferries, which are vessels for day or overnight short-sea trips moving passengers and vehicles (whether road or rail); ocean liners, which typically are passenger or passenger-cargo vessels transporting passengers and often cargo on longer line voyages; and cruise ships, which often transport passengers on round-trips, in which the trip itself and the attractions of the ship and ports visited are the principal draw.
Although some ships have characteristics of both types, the design priorities of the two forms are different: ocean liners value speed and traditional luxury while cruise ships value amenities (swimming pools, theaters, ball rooms, casinos, sports facilities, etc.) rather than speed. 

58. Queen Mary 2 345m Transatlantic Ocean Liner
Passenger Ships
Queen Mary 2 345m Transatlantic Ocean Liner

59. Passenger Ships