Hull and Structure Flashcards
AMI Systems Hull and Structure
Aft
An adjective or adverb meaning, towards the stern (rear) of the ship.
After Peak
Aftermost tank or compartment of a ship.
After Perpendicular
A line to the base line intersecting the after edge of the rudder post at the designed load water line. For stern counters that are well submerged, such as “cruiser sterns,” barges, and similar sterns. The after perpendicular is a line to the base line intersecting the after side of the stern counter at the designed load water line.
Air ports
Often referred to as side scuttles or port holes.
Amidship
The mid or center transverse plane of a vessel located midway between the forward and after perpendiculars.
Anchor
The purpose of the anchor gear or ground tackle is to secure a ship to the seabed in shallow water. Reasons for doing so can be the ship has to wait until a berth becomes available, to load or discharge cargo when a port does not have a berth alongside for the ship, to help with maneuvering in emergency to avoid grounding. In general, ships have two bow anchors and sometimes a stern anchor. There are two bow anchors for safety. Under normal circumstances, one anchor is sufficient, but under severe weather conditions or in a strong current both anchors may be needed. Also, if one anchor fails the second anchor is a backup.
Anchor Chain
An anchor chain is a chain connecting a ship to its anchor. The chain runs from the chain locker, through the Sperling pipe, via the gypsy wheel of the windlass, through the hawse pipe, to the anchor. The anchor chain consists of links with studs to prevent kinks in the chain (stud link chain).
Anode
Cathodic protection using a sacrificial material (usually zinc or aluminum). Intended to protect the Hull structure from corrosion.
Appendage
An underwater surface which protrudes from a hull. That’s to say any sort of keel, rudder, or skeg.
Athwartships or Transverse
Across the ship, at right angles to the keel.
Auxiliaries
Machinery other than main propulsive machinery.
Baffle
A plate or structure placed in the line of flow of fluids or gases to prevent the free flow in order to slow down or stop fluids from surging (e.g. oil tanks). Increases the stability and prevents the center of gravity moving when fluids shift from one side to another.
Ballast
Weight (usually sea water in tanks) loaded into a ship to increase stability when the ship is empty, or when cargo, etc., has a high vertical center of gravity. Also, used to control trim.
Base Line
Horizontal reference line, usually at the lowest boundary. For vessels with a flat keel plate outside of the bottom strakes, the base line is at the top of the flat keel. For vessels with a hanging bar keel, the base line is usually at the lower contour of the molded surface. For vessels with a designed trim or drag, the base line is at the lowest point.
Bilge
Rounded portion of hull between side and bottom.
Bilge Keel (or Rolling Chock)
A longitudinal member fitted to the outside of the shell on the bilge strake of plating to prevent excessive rolling of the ship.
Bitter End
The inboard end of a mooring line or anchor chain.
Bitts
A pair of short, vertical wooden or iron uprights for securing mooring or towing lines.
Bollard
An upright, somewhat stronger than a bitt, on a pier or wharf: used for mooring lines.
Boom
A term applied to a spar used in handling cargo.
Bow
The front of a vessel.
Bow Thruster
A motor driving a propeller near the bow that operates laterally to move the bow one way or the other to help with maneuvering.
Bracket
A steel plate, usually of triangular shape, and commonly with a reinforcing flange, used to stiffen or tie beam angles to bulkheads, frames to longitudinals, or any two structural parts which meet at an angle, in order to strengthen the joint against flexing.
Brow
A portable gangway or gangplank.
Bulbous Bow
A protruding bulb at the front of a ship that may be entirely underwater when the ship is fully loaded. A bulbous bow reduces the drag of a large ship underway by creating a wave of its own that partially negates the bow wave of the ship. This increases speed, fuel efficiency, stability, and the range of a large ship underway by as much as 15%.
Bulkhead
A partition between compartments. Transverse, extending athwartships. Longitudinal, extending fore-and-aft.
Bulkhead Deck
The uppermost deck to which watertight bulkheads are continuous.
Bulwark
The extension of a ship’s side above the level of the weather deck.
Buoyancy
An upward force exerted by a fluid, that opposes the weight of an immersed object.
Butts
The transverse joints in a vessel’s hull.
Camber
The transverse curvature of a deck.
Capstans
The capstan consists of a vertical warping drum with a vertical drive shaft that is driven either electrically, hydraulically, or electro-hydraulically. If the capstan is combined with a gypsy (or cat’s head) it can be used to control the anchor (i.e. a vertical anchor windlass).
Cavitation
A phenomenon in which rapid changes of pressure in a liquid lead to the formation of small vapor-filled cavities (or bubbles) in places where the pressure is relatively low.
Centerline
The fore-and-aft line at the middle of the ship.
Chain Locker
Chain lockers are high and narrow, making them self-stowing. This means that the stacked chain cannot fall over in bad weather. A chain locker is considered a confined space. The end of the chain, the bitter end, is secured to an end connection in the chain locker, with a release outside the locker.
Chock
A hole or ring attached to the hull to guide a line via that point; an opening in a ship’s bulwark, normally oval in shape, designed to allow mooring lines to be fastened to cleats or bits mounted to the ship’s deck.
Cleat
A cleat is a device used for securing a line used on a vessel for mooring purposes.
Coaming
The plates and shapes making up the boundaries of a hatch or skylight. Also, the piece between the deck and the lower skill of a doorway.
Cofferdam
The void space between two bulkheads or decks located close together used to isolate spaces from each other. Also called voids.
Collar
Filler plate used around a shape where it passes through plating for watertightness.
Collision Bulkhead
First complete watertight bulkhead from bow of shin.
Crane
Cranes are lifting devices on board Mobile Offshore Drilling Units (MODUs), Barges, Cargo and Tank vessels, and some Passenger vessels. Cranes are used to lift machinery, product service hoses, product, cargo and supplies.
Davit
Apparatus for lowering or raising lifeboats: a curved spar at the deck’s edge for hauling light loads.
Deadrise
The transverse angular rise of a vessel’s bottom from the base line measured at the vessel’s side.
Deadweight
The difference between a ship’s loaded and light displacement. Total deadweight refers to the carrying capacity of a ship’s cargo deadweight is total deadweight less fuel, water, stores, dunnage and other items necessary for use on the voyage.
Delamination
General term to describe when congruous laminate materials start to separate into layers.
Depth
The vertical measurement from the main deck at side to the base line or bottom of hull.
Displacement
The weight of water in long tons which a floating ship displaces. Light displacement is the weight of the ship with crew and ordinary stores aboard, but excluding cargo, fuel, and passengers. Loaded displacement is the weight of the ship at her maximum draft with crew, stores, cargo, fuel, and passengers.
Dogs
Closure fittings for watertight or weathertight doors and/or hatches.