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

"chemical tanker" means a cargo ship constructed or adapted and used for the carriage in bulk of any liquid product listed in Chapter 17 of the IBC

Code;

"International Bulk Chemical Code (IBC Code)" means the International

Code for the Construction and Equipment of Ships Carrying Dangerous

Liquid Chemicals 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% of the estimated mass of all structural material, whichever is less.

Application to chemical tankers.