237. For the purpose of this Part, unless expressly provided otherwise-

"gas carrier" means a cargo ship constructed or adapted and used for the carriage in bulk of any liquefied gas or other product listed in Chapter 19 of the IGC Code;

"International Gas Carrier Code (IGC Code)" means the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in

Bulk adopted by the Organisation and as amended and adopted by the

Organisation from time to time;

"ship constructed" means a ship the keel of which is laid or which is at a similar stage of construction;

"similar stage of construction" means the stage at which-

(a} construction identifiable with a specific ship begins; and

(b} assembly of that ship has commenced comprising at least 50

tonnes or 1 o/o of the estimated mass of all structural material, whichever is less.

Application to gas carriers.