Compartment (ship)
A compartment is a portion of the space within a ship defined vertically between decks and horizontally between bulkheads. It is analogous to a room within a building, and may provide watertight subdivision of the ship's hull important in retaining buoyancy if the hull is damaged. Subdivision of a ship's hull into watertight compartments is called compartmentation.
History
Bulkhead watertight compartments were originally invented by the Chinese. These compartments strengthened the junks and slowed flooding in case of holing during the Han and Song dynasties.[1][2][3][4] The wide application of Chinese watertight compartments soon spread to the Europeans through the Indian and Arab merchants.[5][6]
The economics of early unsinkable passenger ships was scrutinized in an 1882 Scientific American article.[7]
Watertight subdivision
Watertight subdivision limits loss of buoyancy and
A ship will sink if the transverse bulkheads are so far apart that flooding a single compartment would consume all the ship's reserve buoyancy. Aside from the possible protection of machinery, or areas most susceptible to damage, such a ship would be no better than a ship without watertight subdivision, and is called a one-compartment ship. A ship capable of remaining afloat when any single watertight compartment is flooded is called a two-compartment ship, but damage destroying the tightness of a transverse bulkhead may cause flooding of two compartments and loss of the ship. A ship able to remain afloat with any two compartments flooded is called a three-compartment ship, and will withstand damage to one transverse bulkhead.[8]
After the
Doors
Three types of doors are commonly used between compartments. A closed watertight door is structurally capable of withstanding the same pressures as the watertight bulkheads they penetrate, although such doors require frequent maintenance to maintain effective seals, and must, of course, be kept closed to effectively contain flooding.[8]
A closed weathertight door can seal out spray and periodic minor flow over weather decks, but may leak during immersion. These outward opening doors are useful at weather deck entrances to compartments above the main deck.[8]
Joiner doors are similar to doors used in conventional buildings ashore. They afford privacy and temperature control for compartments formed by non-structural bulkheads within the ship's hull.[8]
Nomenclature
Compartments are identified by the deck forming the floor of that compartment. Different types of ships have different deck naming conventions. Passenger ships often use letters of the alphabet sequentially down from A deck (the highest) above B deck, and B deck above C deck, and so forth. Another popular naming convention is numbering the main deck 1, the deck below it 2 (or the second deck), and the deck below that the third deck, and so forth. Decks above the main deck may be named, like the bridge deck or poop deck,[9] or they may be numbered upwards from the main deck with a zero prefix: 01 above the main deck, 02 deck above 01, and so forth.[10]
The
The centerline position code is zero for a compartment on the ship's centerline, odd numbers for compartments entirely to starboard of the centerline, and even numbers for compartments entirely to port. For compartments sharing the same deck and forward frame, the first two parts of the code are identical, and the third part of the code is numbered outward from the centerline. For example, four main-deck compartments at frame 90 would be 1-90-1-L inboard and 1-90-3-L outboard on the starboard side of the ship and 1-90-2-L inboard and 1-90-4-L outboard on the port side.[10]
The fourth part of the code is:[11]
- A for store rooms (or AA for cargo holds)
- C for crewed communication or control centers
- E for crewed engineering machinery spaces
- F for oil storage tanks (or FF for oil cargo tanks)
- G for gasoline-storage tanks (or GG for gasoline cargo tanks)
- J for JP-5storage tanks (or JJ for JP-5 cargo tanks)
- K for chemical-storage spaces
- L for living spaces, including , and passageways
- M for ammunition magazines
- Q for miscellaneous spaces not otherwise coded, including laundry, galley, pantries, wiring trunks, uncrewed engineering, electrical and electronic spaces, shops, and offices
- T for vertical-access trunks (escape trunks)
- V for void (empty) spaces
- W for water-storage tanks
See also
References
- Manning, George Charles (1930). Manual of Naval Architecture. New York: D. Van Nostrand Company.
- Morrell, Robert W. (1931). Oil Tankers (2nd ed.). New York: Simmons-Boardman Publishing Company.
Notes
- ^ Harper, David Adamson (2011) [2011]. KWANGCHOW - Freddy Everard On The China Seas. BookBaby (published December 30, 2011).
- ISBN 9780762433674.
- ^ Du Bois, George (2014). Understanding China: Dangerous Resentments. Trafford Publishing (published November 8, 2014).
- ISBN 978-1434392787.
- ISBN 978-0470659632.
- ISBN 978-0822630333.
- ^ Scientific American. Munn & Company. 1882-02-11. p. 87.
- ^ a b c d e f Manning, pp.146-148
- ^ Manning, p.145
- ^ a b c "SHIP COMPARTMENTATION AND WATERTIGHT INTEGRITY" (PDF). United States Navy. Retrieved 12 January 2014.
- ^ "Compartment Letters for Ships" (PDF). United States Navy. Retrieved 24 February 2018.