Any variety of hatch cover, which hinges and folds during opening.

An aerated solution that is used for fire prevention and fire-fighting. Foam is an efficient agent for extinguishing most liquid petroleum fires.

A foam system has a storage tanks containing foam concentrate.

The mixture produced by diluting foam concentrate with water before processing to make foam.

In this type of a fender, the core consists of closed-cell, resilient, energy absorbing foam covered with protective, seamless polyurethane elastomer skin.

Fixed, low- and high-expansion foam systems are permitted in the machinery spaces and fixed, low-expansion systems are required on cargo tank decks of tankers.

The full strength liquid received from the supplier, which is diluted and processed to produce foam. When using portable foam making equipment the concentrate is usually introduced to the system directly from the 25 litre storage drums.

An arc welding process that uses an arc between a continuous filler metal electrode and the weld pool.

A ship that has no superstructure on the freeboard deck.

A roll stabilisation system using an athwartships tunnel or tank connecting two wing tanks. The water movement is out of phase with the rolling motion and creates a moment which counteracts the roll.

A liquid, a gas or combination thereof.

It consists of a flue gas system supplemented by a separate small (500 Nm3/h) inert gas generator. The flue gas system covers the bulk of the inerting during cargo unloading, and the topping up generator tops up tank pressures during the sea voyage.

If available, flue gas from ship boilers can be used for inerting. The flue gas system washes and cools the boiler flue gas, and delivers it to the cargo tanks during cargo unloading and tank washing.

A preheater arranged in the flue gas duct of boiler used for preheating of feedwater with no steam produced.

A bottom transverse member mounted in the double bottom to support the inner bottom plating, can be watertight, solid or a bracket construction.

The uncontrolled entry of seawater into a tank or compartment as a result of damage.

The floodable length at any point in the length of the ship is the maximum portion of the length, having its centre at the point in question, which can be symmetrically flooded at the prescribed permeability, without immersing the margin line.

Watertight doors provided to increase the damage stability of the ro-ro ship by restricting the movement of any water along the deck and therefore reducing the free water surface area.

A process by which two or more particles aggregate without loosing their individual identities.

A method of launching a survival craft whereby the craft is automatically released from a sinking ship and is ready for use, (SOLAS, Chapter III).