Ship Terminology

**Bunkerbarge** · 10-04-2006

I said a while ago that I would start a thread of ship terminology so I have finally made a start. I have tried to keep it to parts of a vessel rather than stray into the realms of other engineering aspects so that it remains interesting for the model boater.

So unfortunately you are not going to get the giggle of "Pet Cocks", "Brass Nipples" or "Male /Female" fittings Etc...etc...

A

Abaft: Position on a vessel near the stern.
Abeam: Another ship or object on either side of and in line with a vessel.
Abaft the beam: Term referring to another vessel or shore location to the rear of a line drawn across the beam of a ship.
A-Bracket: Bracket resembling the letter “A” laying on its side. Certain multiple screw merchant ships and many warships have propeller shafts extending outside the hull, forward of the sternpost. Such shafts are supported by a bearing in an A-bracket attached to the hull.
Aft Peak: A watertight compartment between rear watertight bulkhead and the stern.
Aft Perpendicular: A line drawn perpendicular to the waterline where the after edge of the rudder post meets the Summer Load line.
Azimuth Thruster: A thruster that can rotate through 360 degrees, fixed or retractable.

**Bunkerbarge** · 10-04-2006

B

Balanced Rudder: A rudder type in which a proportion of the rudder area, 25-30 % is forward of the axis of rotation. This is to reduce the required torque at the rudder stock.
Beam ends: When a vessel has heeled over to such an extent that there is no righting moment left to bring it back to the normal upright position. Also known as world ends or kiss your ass goodbye.
Beam: The maximum breadth of the vessel.
Belfast Bow: name given to raked stem introduced by Harland and Wolff of Belfast, giving a large foc’s’le deck.
Bilge: Curved portion, often circular, between bottom and side shell plating and the lower parts of holds, tanks and machinery spaces.
Bilge Keel: External fin at round of bilge to reduce rolling. May extend outwards from the vessel by up to 1 Metre in width. Extends fore and aft approximately 2/3 the length of the vessel.
Bilge radius: Radius of the shell plating that joins the side shell to the bottom shell of the hull, measured at the midships section.
Bilge strake: Continuous horizontal fore and aft strip of plating from stem to stern in way of the bilge.
Binnacle: Stand of wood or metal in which a compass is suspended. The cover protects the compass from weather and reduces glare from external lighting.
Bitt: Strong part of ships structure, generally based on the keel and attached firmly to a main deck to which a hawser or warp can be hitched when exceptionally heavy loads are applied such as when the vessel is being towed.
Bitter end: End of the anchor cable secured in the chain locker by a clench pin.
Block Coefficient: Ratio of the displacement of a ship to a given waterline and the volume of the circumscribing block having the same length, breadth and draught of the ship.
Bollard: Large and firmly secured post of circular section for securing hawsers and mooring ropes. Often fitted in pairs on the same base plate.
Boot Topping: Area of a ships side immediately above and below the deep load line. Particularly susceptible to marine weed growth and often coated with specially formulated anti-fouling paint.
Boss: Centre portion of propeller.
Bow: The forward end of the ship.
Bower anchors: The two largest anchors in a ship carried permanently attached to their cables, one on either side of the bow.
Bow thruster: Manoeuvring propeller installed at or near the bow, within a transverse tunnel, for docking assistance, or maintaining vessel heading.
Breadth moulded: Measured at midships and is maximum breadth over the frames.
Break: Point where a side shell plating section drops to the deck below such as in a poop or foc’s’le.
Breast hook: Triangular plate bracket joining port and stbd side stringers at the stem, holding both sides of the ship together.
Breast plate: Horizontal plate that connects shell plating at the stem.
Bridge: Superstructure erection above the freeboard deck generally extending to the ships side giving a clear view from which the ship can be manoeuvred.
Bridge wings: Open portion of the bridge extending from the wheelhouse to the side of the vessel.
Bulbous bow: Protruding bow below the waterline intended to reduce the vessels resistance to motion by breaking the creation of the wake.
Bulkhead: Vertical partition subdividing a ships interior into compartments.
Bulwarks: Vertical plating erected at the gunwhales of a ship to prevent persons being washed overboard and to reduce the water breaking over the deck in a seaway.
Bunker: Compartment where fuel oil or coal for ships engines or boilers is stored.
Buttock: Breadth of a ship where the hull rounds down to the stern.
Butt strap: Connecting metal strap covering a butt joint between two plates to give strength to the joint.

Nigel.D · 10-04-2006

From now on when you loose an argument you are (beam ends) Gospel according to Bunkerbarge(richard)

**Bunkerbarge** · 10-04-2006

I actually thought I had been quite close to it a couple of times in the past on the North Atlantic but the fact that am writing this would indicate that we actually didn't!!

Nigel.D · 11-04-2006

Wow Richard I never knew there was such a huge range of terminology please carry on with this

**wonwinglo** · 11-04-2006

For a landlubber like myself this is excellent reference material Bunkers.

**Bunkerbarge** · 11-04-2006

I spent an hour doing C this morning and lost it all in the process of saving it to my pen drive. I was not a happy teddy!!

**Bunkerbarge** · 11-04-2006

C

Cable Stopper: Device used to secure the anchor cable and take the load off the windlass when the vessel is riding at anchor.
Camber: Curvature of the deck in a transverse direction. Camber is measured between the deck height at the centre and the deck height at the side. Also called Round of beam.
Cant Frames: Frame not square to the centre line such as in a cruiser stern. Not required with a Transom Stern.
Capstan: Barrel device or rolling concave drum, on a vertical axis, used for heaving in mooring lines or anchor cables.
Carvel Built: Type of ships plating made flush by Vee Butt welding or Butt Strap riveting.
Caulking: 1) making jopints watertight by filling seams of deck planks with Oakum. 2) Method of closing butts and seams of riveted steel plating.
Ceiling: Timber placed across the floor of a cargo hold to protect it from damage.
Cellular: Structural arrangement where a compartment is divided into small spaces such as a double bottom.
Centre Girder: Continuous longitudinal girder in the double bottom that runs fore and aft on the centre line.
Centre of Buoyancy: The centroid of the underwater volume and point through which the total buoyancy force it assumed to act. For a ship to float on an even keel the centre of buoyancy must be under the centre of gravity. The position of the centre of buoyancy is dictated by the loading of the vessel.
Centre of Gravity: The point through which the total mass of the vessel is assumed to act. The position of the centre of gravity of a ship depends on the distribution of internal masses. The stability of the vessel is directly related to the difference vertically between the centre of buoyancy and the centre of gravity. The greater this distance the greater the stability.
Chain Locker: A compartment that holds the anchor chain and also contains the ‘Bitter End’ connection.
Chock: 1) Smooth surfaced fitting at the weather deck side through which mooring ropes are led. 2) Wedge for securing a hatch cover or adjusting the alignment of a piece of machinery such as an engine, pump or gearbox.
Clinker Built: Each strake or plank of the hull construction overlaps the strake below. Generally used only in small boat building.
Clipper Bow: A bow where the stem post is concave in form as it rises from the waterline forming a bowed shape, like the Kreigsmarine “Atlantic Bow”.
Coaming: vertical plating bounding a hatchway. Heights of coamings depend on hatch position, some being more exposed than others. Coaming may be omitted altogether if directly secured steel covers are fitted. The height of the coaming is dictated by the Merchant Shipping (Load Line) Rules of 1968.
Cofferdam: A void or empty space between two bulkheads or floors preventing contamination of the two spaces contents.
Collision Bulkhead: Foremost transverse watertight bulkhead extending to the freeboard deck. Designed to limit entry of water in the event of a bow collision.
Companionway: 1) Set of steps leading between decks. 2) Ladder used for embarking and disembarking the vessel.
Compartment: Subdivision of the hull by transverse watertight bulkheads, creating compartments that allow the vessel to remain afloat and upright after flooding.
Conning Position: Part of the bridge with a commanding view from which the vessel may be conned (steered) when underway.
Controllable Pitch Propeller: Propeller made up of a boss with separate blades mounted onto it. An internal mechanism enables the blades to move simultaneously through an arc to change the pitch angle and therefore the pitch. Astern thrust can be generated without the need to reverse the rotation of the shaft. CPP units are generally not as efficient as fixed pitch propellers so tend to be used where manoeuvrability is more of a consideration than efficiency such as in ferries.
Crows Nest: Look out position on the upper foremast. Rarely used nowadays.
Crutches: Posts or saddles on the deck forming a crutch that the ends of derricks can rest and be secured when not in use.
Cycloidal Propeller: Combined steering and propulsion device comprising of a number of vertical blades arranged to rotate and revolve to give thrust in any desired direction. The most common form of these is the Voith Schneider unit.

**Bunkerbarge** · 16-04-2006

D

Damping: A ship (boat) has six degrees of freedom, Heaving, Swaying, Surging, Rolling, Pitching and Yawing. The first three are linear motions. Rolling is rotation about a longitudinal axis, pitching is rotation about a transverse axis and yawing is rotation about a vertical axis. It is often necessary to dampen these actions and many devices from stabilizer fins to passive water tanks have been used to this effect.
Davits: Supports under which lifeboats and liferafts are stored and launched.
Deadlight: Steel cover used to protect a porthole in heavy weather. Usually secured with screws and wingnuts.
Deck: Horizontal steel or wooden flooring usually extending from one side of the vessel to the other.
Deck Head: Underside of the deck.
Deck House: Superstructure found on upper decks of a vessel which do not extend the full width of the vessel.
Deck, Main: Principal or strength deck that for structural reasons is an essential part of the ships structure. Usually the deck to which vertical watertight bulkheads terminate.
Deck, Shelter: Deck above the main deck. If this deck is not permanently closed against the weather it is exempt from tonnage dues.
Deck Tween: In a cargo ship any deck between the bottom of the ship and the main deck.
Deep Tanks: Tanks extending from the shell or double bottom up to or beyond the lowest deck. May serve the dual purpose of carrying liquid in bulk or ballast.
Depth Moulded: Vertical distance at Midships from the Keel to the uppermost deck, taken inside the ships plating.
Devils Claw: Claw attached to the fore part of a Windlass which can be fitted over a link in the anchor cable thus enabling the weight of the anchor to be taken off the windlass when the vessel is under way.
Displacement: Weight of water in tones, displaced by a ship. Loaded displacement includes cargo, stores passengers, and crew. Light displacement is the tonnage displaced without these items. The weight of a Warship is always quoted as displacement tonnage.
Docking Bracket: Vertical stiffener fitted between each transverse bulkhead to support the centerline girder of an oil tanker.
Docking Plug: Threaded bolt usually with a socket hex head, fitted to all double bottom yanks and spaces to allow drainage prior to examination in a dry dock.
Dodger: Screen used as a protection from sea spray.
Double Bottom: Space between the outer hull plating and the inner bottom plating of the ship.
Double Skin: A method of construction that utilises an outer and an inner hull. This method of construction is now compulsory for oil and product carriers.
Doubling Plates: Extra plates, bars or stiffeners added to strengthen sections where holes have been cut.
Down to her Marks: When a vessel is fully loaded to her maximum draught for her relevant load line.
Drain Hat: Bilge water collecting pointing a continuous tank top designed to exclude large waste material.
Draught: Distance from the bottom of the ship to the loaded water line. If the waterline is parallel to the keel the vessel is said to be on an even keel or on the keel. If not the vessel is said to be trimmed by either the head or the stern.
Duct Keel: Space formed by twin longitudinal girders in a ships double bottom. Provides longitudinal strength and is usually used to carry longitudinal pipe mains such as ballast and fuel. Big ships can have a small cart on rails that you sit on and pull yourself along to gain access to valves and fittings for inspection and repair. It is one of the scariest places I have ever been.

rjwood_uk · 16-04-2006

this is all great stuff richard!!! are you getting this from a book or your head???

if its all in your head i dont know how you can remember it all off by heart.....and in alphabetica order!!! :P