A,B,C,D In Ship Terminology

A,B,C,D In Ship Terminology


Access Holes – Holes cut in the ship’s structure to permit entering or leaving various compartments.
After perpendicular – A vertical straight line at or near the after edge of the rudder post
Amidships – At the midship section of the ship
Accommodation ladder – a portable ladder on a ship’s side for people boarding from small boats or from a pier.
Aft – Near or towards the stern of the shipShip’s terms
Aftermost – The furthest aft.
Aft Peak Bulkhead – The first main transverse watertight bulkhead forward of the stern.
Anchor – A heavy object of steel attached to a vessel by a cable and/or chain and cast overboard
to keep the vessel in place.
Athwart ship – Perpendicular to the fore and aft centerline of the ship


Ballast – Any substance other then cargo, which is usually placed/loaded in the inner compartment of a ship to produce a desired trim or improve stability.Ship’s terms
Bay – It is an area between adjacent transverse frames or transverse bulkheads
Beam – The width of the ship at its widest point
Bilge – Internally, the lowest part of the ship.
Bilge Keel – Piece of plate set perpendicular to the ship’s shell along her bilge for reducing the rolling.
Bilge strake – It is the strake at the turn of the bilge extending outward to a point where the side rises
Bow – The forward end of the ship.Ship’s terms
Boss – The curved swelling portion of the ship’s hull around the propeller shaft.
Breakwater – A guard plate preventing solids or liquid from sweeping into the deck.
Breast hook – A triangular plate bracket joining the port and starboard structural members at the stem.
Bridle – A V-shaped chain, wire or rope attached to a vessel being towed, to which the towline is
attached .Ship’s terms
Body plan – A drawing which shows the frame lines in elevation.
Boat deck – a deck on which the lifeboats are kept.
Bollards – A round tie posts to which the mooring lines are made fast.
Booby hatch – A watertight covering over a deck opening which is used for a stairway or ladder.
Bridge – An elevated structure extending across or over the weather deck containing the stations for the control of the ship and communications.
Bridge deck – A deck of superstructure midship Bulkhead – A vertical partition separating the
compartments in a ship.
Bulkhead deck – It is the uppermost deck to which the transverse watertight bulkheads and
shell are carried.
Bulkhead Structure – Is a transverse or longitudinal bulkhead plating with stiffeners and girders.
Bulwark – It is the vertical plating immediately above the upper edge of the main deck at side.
Butt – The joint formed when two plates are placed edge to edge


Cabin – An enclosed compartment of a ship used as living quarter.
Camber – The athwart ship rise of a deck.Ship’s terms

Cargo hatch – a large opening in the deck which permits loading of the cargo inside Ship.
Cargo port – an opening in the ship’s side used for loading and unloading cargo Cargo area – that part of the ship which carries cargo.
Cargo hold bulkhead – boundary bulkhead separating the cargo holds.
Carlings – supports, usually in a fore and aft direction, of flat plate/bar, welded between transverse deck beams.
Casing – covering or bulkhead around or about any space for protection.
Ceiling wood –sheathing on tank top to protect the cargo and ship structure.
Center line – middle line of the ship extending from stem to stern
Chain locker – compartment in the forward part of the ship for storing the anchor chain.
Chain pipe – A pipe for passage of chain from deck to chain locker
Classification - the certification process administered by a an agency whereby the ship is constructed and maintained to the agency’s requirements.
Cofferdams – any space between two bulkheads or decks primarily designed as a safeguard against oil leakage from one compartment to another.
Collar – a welded plate used to close a beam or frame penetration through plating.
Collision bulkhead - the foremost main transverse watertight bulkhead
Companionway - a covered stairway leading down from the open deck
Compartment - a sub-division of space or room in a ship
Confined space - a space identified by one of the following characteristics, limited opening for entry or exit, unfavorable natural ventilation or not designed for continuous worker occupancy.Ship’s terms


Dead rise - a rise or upward slope of the bottom of the ship from the keel to the bilge.
Deadweight – cargo carrying capacity of the ship.
Deck house - A structure on the freeboard or superstructure deck not extending from side to side.
Derrick - a device for hoisting heavy weights or cargo
Displacement - Total weight of the ship, when afloat, including every thing on board.
Discharges - any piping leading through the ship’s sides for conveying bilge water, drains, etc.
Dog - a small bent metal fitting used in closing doors,hatches etc.
Double Bottom - is the structure of the ship bounded by the bottom shell and the inner bottom plating
Doublers plate - a plate fitted over another plate for extra strength
Duct keel - is a keel built of plates in box form, extendingthe length of the cargo hold.Ship’s terms


Enclosed superstructure - is the superstructure with bulkheads forward and fitted with weather tight doors and closing appliances.
Erecting - the process of hoisting and joining the various parts of the ship’s hull. These parts could be in various sizes and called micro panels, panels, blocks, mega blocks.


Fabricate - to make assemblies from raw steel materials
Face plate - narrow stiffening plate along the edge of any frame, stiffeners or other structural members, either welded or integral part of the member.
Fairing - reforming distorted plating to its original shape

Fender - any device used to absorb the shock and prevent damage to ship’s hull when coming against a
jetty or against any other object.

Forecastle - short superstructure situated at the bow.
Foremast - the forward most mast on a vessel
Forepeak - is the area of the ship forward of the collision bulkhead.
Forepeak Bulkhead - Same as collision bulkhead

Frame spacing - the fore and aft distance between adjacent frames.
Freeboard - vertical distance from the upper watertight deck to the waterline when the ship is fully loaded.
Freeboard marks - making done amidships on both sides of the ship, to mark the position up to which the ship can load
Freeboard deck - normally the uppermost complete deck exposed to weather and sea, which has permanent means of closing all openings.
Freeing port - is an opening in the bulwarks to allow the water shipped on deck to run freely overboard.

Funnel - a smoke stack of a vessel


Gangway - is a raised walkway between superstructure such as between the bridge and forecastle or between bridge and poop.
Galley - kitchen of a ship
Garboard strake - the longitudinal plating next to the keel
Girder - is a collective term for primary member supporting structural members.
Girth - any specified length
Grating - light platform or walkway made up of metal bars, used for access to the machinery
Gross tonnage - overall volume of the ship.
Gunwale - is the upper edge of the ship’s side


Hatch – An opening in the deck for passage of cargo
Hatch Coaming - is the vertical plating built around the hatchways, to prevent the water from entering the hold.
Hatch Covers - Steel covers fitted over the hatchways to prevent the ingress on water in the holds, and also as supporting structure for the deck cargo.
Hawse pipe - a pipe passage from the deck at bow to the ship side for the passage of the anchor chain
Hawser - a large rope used for towing or mooring
Heel - inclination of the ship to one side with respect to the center line.
Hull - the body of the ship, including the shell plating,decks, bulkheads, and framing Inboard - inside the ship, toward the center line


Inner bottom - plating forming the upper surface of the double bottom


Keel - main structural member or the backbone of a ship running longitudinal along the center line of the ship.
Knot - speed unit of one nautical mile (6080 feet)
Kort nozzle - a steel ring surrounding the propeller


Ladder - inclined steps used on ships
Launching – process of putting the vessel in water by allowing it to slide down on greased skids.
Length between perpendiculars - length measured between the forward and aft perpendiculars.
Length overall - length of the ship measured from the extreme forward to the aftermost point of the ship.
Lightening hole - a hole cut tin a plate of a structural member to reduce the weight

List - to lean over to one side
Load waterline - line of surface of a ship when loaded to its waterline
Longitudinal - a shell, deck or a stiffener running in a fore and aft direction


Main Deck – usually the uppermost continuous deck
Mast – a pole or similar structure on which the lights, and signals can be placed or displayed.
Manhole – a opening in a deck or any other member, which provides access for a man
Midship – at or near the middle point of a ship
Midship section – a cross section through the middle of a ship.
Mooring – securing a after deducting the total volume for certain ship by several lines or cables


Net tonnage – the figure spaces which can not be used for cargo


Outboard – away from the center line of the ship
Overboard – outside, over the side of the ship into water


Peak – a narrow compartment at either end of the ship
Pillar – a vertical member which provides support to a deck girder
Pintle – a pin on which the rudder hinges
Poop – a space below an enclosed superstructure at extreme aft end of the ship
Poop deck – first deck above main deck at aft end.
Port – The left hand side of the ship when looking towards forward side
Porthole – a circular opening in ship’s side for ventilation and natural lighting.
Profile – a side elevation of the ship
Propeller – a rotating device which drives the ship through the water


Rigging – ropes, masts, wire ropes, lashings etc.
Roll – motion of the ship from side to side
Rudder – a flat piece of steel attached upright to the stern post at the stern by pintles, gudgeons or hinges, so that it can be turned, causing the vessel to turn.
Rudder Post – after post of the stern frame to which the rudder is attached.Ship’s terms
Rudder Stock – shank of the rudder which extends from the rudder to the steering gear


Sagging – straining of the ship which makes the middle portion of the ship lower than the aft and the forward end

Scupper – a deck drain
Scuttle – a small opening in deck or shell usually fitted with a cover, for access to a compartment
Sea chest – a compartment through which the sea water is admitted or discharged
Shedder Pates – slanted plates fitted in dry cargo holds to prevent undesired pockets of cargo.
Sheer strake – top strake of a ship’s side
Shell Expansion – a plan showing all the shell plates.
Skeg – a framed steel plate structure which acts as a fixed rudder under the stern
Sheer – an upward curvature of a ship’s deck in the fore and aft direction
Shell plates – plates forming the outer skin of the ship
Skylight – an opening in the deck to give to give air and light to the compartment below
Starboard – the right hand side of a ship when looking forward.
Stem – a piece of bar or plating on which the ship’s outside plating terminates
Stern – aftermost part of the ship.
Stern frame – a heavy strength member in single screw ship combining the rudder post
Stern tube – a long bushing or bearing through the stern to support the end of the propeller shaft
Stiffener – a collective term for the secondary supporting structural members
Stool – a structure supporting the cargo hold and tank bulkheads
Strake – a row of shell, deck, bulkhead or other plating
Strength deck – normally the uppermost continuous deck
Stringer – a fore and aft member used to give longitudinal strength
Stringer plate – deck plating which contacts the shellShip’s terms
Superstructure – decked structure on the freeboard deck extending for at least 96 % of the breadth of the ship


Tank top – plating over the double bottom
Tail shaft – a short portion of the propeller shaft passing through the stern tube and carrying the propeller
Tween decks – abbreviation for between decks, placed between the upper deck and the tank top
Trunk – a small casing passing through the deck, used for ladders or ventilation


Void Space – an empty space in a ship


Weather deck – a deck exposed to the weather
Web frame – a frame with a deep web
Windlass - a machine used to hoist the anchors.

# Various books, study material and other online sources has been refereed prior to writing this article but no major part is copied or produced  from any of the source but explained same thing in better detailed way.

Main reference source: Ship Terms by " Society of naval architecture students, Cochin" By Arjun k bharath.

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Author Amit                                                                            

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