Marine and Naval Architecture terms have special meaning. Persons studying ship construction, working on board ship, or dockyard will find these pages useful.

	NATIONAL FLAG	The flag flown by a ship to show her nationality.
	NET CAPACITY	The weight of cargo which a vessel can carry when loaded in salt water to her summer freeboard marks. Also called cargo carrying capacity, cargo deadweight, useful deadweight.
	NET TONNAGE	See Tonnage (Net)
	NRT	Net registered tons. See Tonnage (Net)
	OBO SHIP	A multipurpose ship that can carry ore, dry bulk goods and oil.
	OIL TANKER	A ship designed for transporting oil in bulk
	OPEN REGISTRY	See "flag of convenience" or "flag of necessity"
	ORE CARRIER	A large ship designed for the transportation of ore.
	ORE-BULK-OIL CARRIER	See OBO ship
	OUTBOARD	Away from, the centerline towards the side; outside the hull
	PANAMAX	A vessel designed small enough for passage through the Panama Canal
	PANTING	The pulsation in and out of the bow and stern plating as the ship alternately rises and plunges deep into the water
	PANTING FRAME	The frames in the forward and after portions of the hull framing to strengthen against shell panting
	PARALLEL MIDDLE BODY	The amidships portion of a ship in which the contour of the underwater hull form is unchanged
	PASSENGER SHIP	A ship authorized to carry more than twelve passengers.
	PERIOD OF ROLL	The time occupied in performing one complete roll of a ship as from starboard to port and back to starboard
	PILOT HOUSE	The enclosed space on the navigating bridge from which a ship is controlled when under way. See bridge
	PINTLES	The pins or bolts that hinge the rudder to the gudgeons on the rudder post or sternpost
	POOP	A superstructure fitted at the after end of the upper deck
	PORT	The left-hand side of a ship when facing forward
	PRODUCT CARRIER	A tanker used to carry refined oil products. Normally four different grades of oil can be handled simultaneously.
	QUARTERS	Accommodations.
	RAKE	Fore-and-aft inclination from the vertical
	REEFER	A ship designed for carrying goods requiring refrigeration
	REEFER CONTAINER	An insulated container fitted with a refrigeration unit for carrying cargo requiring temperature control
	RO/RO SHIP	Cargo or ferry ship on which trucks and other vehicles can be driven on and off on ramps through large openings at the bow, stern or side
	RUDDER STOCK	A vertical rudder shaft that connects to the steering gear
	RUDDER STOP	A stout bracket to limit the swing of the rudder to the maximum 37 degree starboard or port
	S.S.	Steamship.
	S/T	Short tons (2,000 lbs.).
	SAGGING	Straining of the ship that tends to make the middle portion lower than the bow and stern (See hogging)
	SCUPPERS	Drains from decks to carry off accumulations of rainwater, condensation or seawater
	SCUTTLE	A small circular or oval opening fitted in decks to provide access
	SEA CHEST	An opening for supplying seawater to condensers, pumps, etc. located in the hull below the waterline and having means for the attachment of the associated piping
	SEA TRIALS	A series of trials done at sea to determine whether the ship has met the specifications of design, modification, or repair
	SEA WORTHINESS	The condition of a vessel with regards to materials, construction, equipment, crew and outfit which is considered safe for the trade in which it is employed
	SEABEE	A self-propelled sea barge larger than the "LASH" but using rollers to move aboard the ship
	SEAWORTHINESS CERTIFICATE	A certificate issued by a classification society surveyor allowing a vessel with a mishap affecting its seaworthiness to proceed to another port where permanent repairs can be carried out.
	SELF-SUSTAINING SHIP	A containership fitted with her own crane for loading and discharging containers
	SELF-TRIMMING SHIP	A ship whose cargo holds are shaped so that the cargo levels by itself.
	SELF-UNLOADER	A bulk carrier which is equipped with cargo unloading gear
	SHEER	The longitudinal curve of a vessel's decks in a vertical plane. Due to sheer, a vessel's deck height above the baseline is higher at the stem and stern than at amidships
	SHEER STRAKE	The course of shell plating at strength deck level
	SHELL EXPANSION	A plan showing the seams and butts, thickness and associated welding or riveting of all plates comprising the shell plating, framing, etc.
	SHELL PLATING	The plates forming the outer side and bottom skin of the hull
	SHELTER DECK	A superstructure deck fitted continuous from stem to stern and fitted with at least one tonnage opening
	SHIFTING	Moving the ship to suit the location of shore cargo loading gear
	SHIFTING BOARD	Portable bulkhead members, generally constructed of wood planking and fitted fore and aft in cargo holds when carrying grain or other cargo to prevent shifting when the ship is rolling
	SHORE	A brace or prop used for support while building a ship
	SHORT TON	2,000 pounds.
	SISTER SHIPS	Ships built on the same design.
	SKEG	A deep, vertical, finlike projection on the bottom of a vessel near the stern
	SKYLIGHT	A glass covered framework fitted over a dock opening for admitting light and air into the compartment below
	SLOP TANK	A tank in a tanker into which the residue of tank washing are pumped.
	SOUNDING PIPE	A pipe leading to the bottom of an oil or water tank, for guiding a sounding tape or jointed rod when measuring the depth of liquid in the tank
	SPARRING	(See Cargo battens)
	SPECTACLE FRAME	A large casting extending outboard from the main hull for supporting for the ends of the propeller shafts in a multi-screw ship
	STABILITY	The ability of a ship to return to her normal upright position when listed by the action of waves, wind, etc.
	STARBOARD	The right-hand side of a ship when facing forward
	STEALER	A single wide plate that is butt-connected to two narrow plates, usually near the ends of a ship.
	STEM	The upright bow frame forming the apex of the intersection of the forward sides of a ship
	STERN FRAME	Large casting attached to th after end of the keel, incorporating the rudder gudgeons and propeller post in single-screw ships
	STERN TUBE	The watertight tube enclosing and supporting the propeller shaft on bearings
	STERN, CLEARWATER	A stern with a "shoeless" stern frame
STERN, CRUISER	A spoon-shaped stern used an most merchant ships designed to give maximum immersed length
STERN, TRANSOM	A square-ended stern used to provide additional hull volume and deck space aft and to decrease resistance in some high speed ships.
STERNPOST	The vertical part of the stern frame to which the rudder is attached
STERNWAY	The reverse movement of a vessel. See astern
STIFF, STIFFNESS	A stiff ship is one which have a short period of roll and therefore will roll uncomfortably
STIFFENER	An angle, T-bar channel, built-up section etc, used to stiffen plating of a bulkhead, etc.
STORE	A general term for provisions, materials and supplies used aboard ship
STOWAGE	The placing of goods in a ship in such a way as to ensure the safety and stability of the ship
STRANDING	The running of a ship on shore on a beach.
STRENGTH DECK	The deck that is designed as the uppermost part of the main hull longitudinal strength girder
STRINGER	A fore-and-aft girder running along the side of a ship at the shell and also to the outboard strake of plating on any deck
STRINGER BAR	The angle connecting the deck plating to the shell plating or to the inside of the frames. The strength deck stringer bar is usually called the gunwale bar
SWASH BULKHEAD	Longitudinal or transverse nonwatertight bulkheads fitted in a tank to decrease the swashing action of the liquid contents as a ship rolls and pitches at sea
SWASH PLATE	A plate serving the purpose of a swash bulkhead, but not extending to the bottom of the tank
T.E.U.	Twenty Foot Equivalent Unit for containers. See containers
TAIL SHAFT	The ship's propeller shaft
TANK-BARGE	A river barge for the carrying of liquid bulk cargo
TANKER	Ship designed for transporting liquid cargo, usually petroleum products
TENDER	A tender ship is one which have a long period of roll but may list excessively in a strong wind and may be dangerous if a hold is flooded following a collision
TEST HEAD	The head or height of a column of water which will give a prescribed pressure on the vertical or horizontal sides of a compartment or tank in order to test its tightness, or strength
TONNAGE (DEADWEIGHT)	See deadweight
TONNAGE (GROSS)	Gross tonnage includes a ship's internal volume, excluding such spaces as the peak, double bottom, deep tanks used only for water ballast, bridge, forecastle, open-ended poop, certain light and air spaces, skylights, anchor and steering gear spaces, toilets, the wheelhouse, and certain passenger spaces
TONNAGE (GROSS, NET)	A measure of the internal volume of spaces within a vessel in which 100 cu.ft.. is 1 ton
TONNAGE (NET)	Net tonnage is the gross tonnage less certain additional spaces such as crew and officer spaces, chart room, and a percentage of the propelling machinery spaces; also see deadweight, displacement, light and displacement, loaded
TONNAGE OPENINGS	Nonwatertight openings in the shelter deck and in the ''tween deck bulkheads immediately below in order to exclude spaces from tonnage measurement and thus obtain reduced gross and net tonnage. The openings could be closed by nonwatertight wood shifting boards or metal covers meeting the tonnage and load line regulations
TRANSOM BEAM	The aftermost transverse deck beam
TRANSOM FRAME	The aftermost transverse side frame
TRIM	The difference between the draft forward and the draft aft. A ship is trimmed by adjusting the location of fuel, cargo, ballast, etc.
TRIMARAN	A triple hulled vessel
TRIPPING BRACKET	Flat bars or plates fitted at various points on deck girders, stiffeners, or beams as reinforcements to prevent their free flanges from tripping
TUG	A boat equiped with powerful engines for towing or pushing large ships or barges
TUMBLEHOME	Inboard slope of a ship's side above the designed waterline
TWEEN DECK	The space between any two adjacent decks