What is ship Ballast?
Heavy material, such as pig iron or water, stored in the bottom of the ship to keep her steady. Modem ships have ballast tanks built into them. When a ship has discharged her cargo and sails empty she is ballasted by flooding water into her ballast tanks to give her stability.
What is ship Berth?
Usually refers to the quay or jetty alongside which a ship lies for loading and unloading cargo. A building berth is the inclined or sloping slipway on which a ship is built and from which she is launched.
What is ship Bilge keel?
Lengthwise keel secured to the hull on either side of the main keel to provide stability.
What is ship Bogie?
An undercarriage used for transporting.
What is ship CAD/CAM?
Computer Assisted (or Aided) Design/ Computer Assisted Manufacture. These are computer programs to assist the Naval Architect and the shipbuilders in designing and building the ship.
What is Caisson?
A dock gate which floats and can be positioned at the dock entrance by sinking it into position. Caissons are used in dry docks and non-tidal basins to prevent the water getting into a dry dock or to stop it from getting out of a non-tidal basin when the tide goes out.
What is ship Centerline?
An imaginary line drawn from the bow to the stem post, dividing the ship in half.
What is ship Cladding?
Plates of iron which are clad or secured to the hull of a wooden ship to give it protection.
What is ship Class?
Collective name for ships of similar size and design.
What is ship Clipper?
The fast ocean-going sailing ships originating in Baltimore in the early 19th century. Such ships, owned by companies in America and Great Britain, used to compete with one another in the tea trade with China and India.
What is ship Composites?
Building materials of different types. A boat or ship is said to be “composite-built” when the frames or ribs are of steel and the hull planking is of wood.
What is ship Container?
The standard ISO-sized containers have modules 10, 20, 30 and 40 feet long. By far the most popular size is 8ft X 8.5ft X 20ft (2435mm X 2590mm X 6055mm).
What is ship Cradle?
Framework shaped to the curvature of the hull, which supports the ship on dry land. Cradles are fitted between the hull of the ship and the launching slipway to keep the hull upright. When the ship is launched, the cradles travel down the slipway with the ship.
What is ship Cylinder?
A circular chamber or hole within an engine which contains the piston.
Cylinder bore The diameter of the piston cylinder in which the piston operates.
What is ship Davit?
An appliance designed for hoisting and lowering boats over the side of a ship.
What is ship Deckhead?
The nautical term for the ceiling of a compartment.
What is ship Deckhouse?
The structure fitted to the upper deck of a ship.
What is ship Derrick?
A large spar rigged as a boom to the mast of a ship and used for hoisting cargoes in and out of ships.
What is ship Displacement?
The amount of water which the hull of a ship displaces in the water (as in Archimedes’ principle). This displacement is measured in tons. The displacement tonnage of a ship can vary, depending on whether she is fully loaded with cargo, or empty.
What is ship Drag chains?
Chains which are secured at one end to the land and at the other end to the hull of a ship before launching. They are used to slow and stop the ship when she enters the water from an inclined launching berth. Drag chains are used in narrow rivers or confined waters.
What is Dredger?
Vessel used in channels, harbors and rivers for deepening the water by excavation of the bed.
What is Dry dock?
A dock where the water is pumped out and in which a ship can be built or repaired: When the work is completed the dock is flooded with water and the ship floated out.
What is ship DWT?
Deadweight tonnage is the weight of cargo which a ship carries: plus the weight of fuel, stores, water ballast, fresh water, crew, passengers and baggage.
What is ship Flame planer?
A machine using a gas torch type flame to cut several steel plates at the same time.
What is ship Floating out?
Method of launching a ship after she has been built or fitted out in a dry dock by flooding the dock and floating her out.
What is ship Frame?
The term given to the ribs of a ship which are shaped to the hull and run from the keel to the upper deck.
What is ship Frame bender?
The machine which shapes the frames or ribs of the ship.
What is ship Galley?
A large vessel powered by oarsmen. Such craft were often fitted with sails.
What is ship Hogging?
Occurs when the bow and stern drop below an imaginary line between them.
What is ship Infra-red emissions?
Electro-magnetic radiation waves produced by machinery in ships and aircraft. The wavelengths of infra-red emissions can only be detected by special receivers.
What is ship Knot?
The measurement of the speed of a ship. One knot is one nautical mile per hour. A nautical mile is longer than a land mile.
What is ship Launchways?
(or launching ways, slipways or just “ways”). Wide, wooden slideways on which the cradles supporting a ship rest. Before the ship is launched, the launchwavs are heavily greased so that the cradles can move easily over them.
What is ship Liquid pressure testing?
When a tank or pressure vessel is constructed it is given a liquid pressure test to ensure that it does not leak.
What is ship Lloyd’s?
Register of Shipping An 18th-century society founded in London, England to define rules regarding the construction of merchant ships.
What is LNG ship/tanker?
Vessels specially constructed to carry liquid natural gas. Natural gas is frozento a very low temperature of minus 163°C which makes the gas liquid. The liquid gas is then pumped into the LNG tanker which has highly insulated tanks to prevent the gas from evaporating.
What is LPG ship/tanker?
The construction of liquid petroleum gas-ships is similar to that of the LNG tankers. Propane or butane gases are frozen to make them liquid and then pumped into LPG tankers.
What is ship Nautical mile?
The length of a nautical mile is 2026 yards (1852 meters). A land mile is shorter: 1760 yards.
What is ship OBO?
A combination bulk carrier which can transport oil, bulk or ore.
What is Panamax?
The largest size of vessel able to go through the Panama Canal.
What is Piston?
A solid cylinder which fits into the engine cylinder. The piston is connected to the crank shaft of the engine by a piston rod. Liquid or gas can be injected into the cylinder under pressure, which forces the piston to move within the cylinder.
What is ship Plate or plating?
Sheets of steel used for building the hull of a ship.
What is ship Radiography (or X-ray)?
The method used for checking that a weld joining two steel plates together has been properly carried out. The X-ray shows up faulty welding or cracks in the weld.
What is ship Roll (or rolling)?
The side-to-side movement of the ship from the upright position. Rolling is caused by the motion of the sea on the ship.
What is ship Sagging?
The bow and the stern are above an imaginary line which joins them so that the keel has dropped.
What is ship Scale Loose?
surface of steel created by rust and heat treatment. Also a chemical deposit in a boiler.
What is ship Scantlings?
The dimensions of all parts of a ship’s hull, including her frames, girders, stringers, plates, etc.
What is ship Screw?
A term used for the propellor of a ship. It is derived from the screw motion of the propellor through the water.
What is ship Scribe, to?
To engrave lines on steel plates by using sharp, pointed tools.
What is ship Sensor?
Device (such as sonar or radar) used to increase the senses of hearing and sight.
What is ship Shearing?
The hull is distorted about the center line or fore and aft line between the bow and stem. This distortion causes the ship to shear off a straight course.
What is ship Ship elevator?
A very large platform on which a ship sits and is then lifted out of the water so that work can be carried out under the water line.
What is ship Shore?
Large pieces of timber which support a vessel in the upright position in dry dock or on a slipway. When a ship dry-docks, shores are placed on each side, between the ship and the dock, while the water is being pumped out. More shores are fitted under the bottom of the ship to support her when the dock is emptied.
What is ship Side-thrust?
The sideways movement of a ship through the water when the bow or stern thrusters are used.
What is ship Sonar?
A sonar-set in a ship can locate submarines under the water by transmitting sound waves towards the submarine. The sound waves bounce back off the submarine to a receiver in the ship. Computers work out the range, speed and depth of the submarine from the sound waves. The sonar principle is also used for measuring the depth of the water, to locate shoals of fish, and wrecks.
What is ship Stabilizers?
Moveable fins fitted in the ship’s hull below the water line, which when operated help to decrease rolling. When not required, the fins are housed inside the hull, and when they are operated they are moved out into the water. The fins are operated by machinery in relation to a gyro in the stabilizer system, endeavoring to bring the ship back to an upright position.
Stern post A vertical piece of metal which supports the stem of a ship. It is located in the center of the stern in line with the keel.
What is ship Straightening roller?
Large rollers which straighten out steel plates and frames.
TEU Twenty-feet Equivalent Units: equivalent to 20ft containers.
What is ship Thrusters?
Propellors fitted in tunnels in the hull of a ship, at right angles to the center-line. They are usually fitted near the bow to assist in moving the ship sideways while at rest. Some ships which have to be accurately positioned have stem as well as bow thrusters.
What is ship Tide Tables?
Time-and-Tide Tables Official publication listing times of the high and low water levels of tides throughout the world.
What is Tug?
Vessels designed to tow (pull) and push ships. Ocean-going tugs are used to help ships in distress at sea, or for towing ships, oil rigs and floating docks over a long distance. Harbor tugs are smaller and are used for berthing large ships, by pushing and pulling them into position.
What is ship Turbine engine?
A turbine is a wheel which is fitted with a large number of angled fins or blades instead of spokes. It is rotated by forcing high pressure steam or hot gases through the blades. A shaft running through the center of the turbine rotates, providing power. The power reaches the propellor shaft and the propellor through a gearbox. Turbine engines are usually fitted in fast warships and in some liners.