For the purposes of this Part
"ship" includes every description of lighter, barge or similar vessel, however propelled and any structure launched and intended for use in navigation as a ship or as a part of a ship;
"shipowner" includes charterer, manager or operator of ship;
"salvage services" means services rendered in direct connection with salvage operations;
"salvor" means any person rendering salvage services;
"salvage operation" includes the operations referred to in section 409(1) (d), (e) and (f);
"Unit of Account" means the special drawing right as defined in section 2 of Article XXI of the Articles of Agreement of the International Monetary Fund.