Hi MFR401,
Draft refers to the maximum keel depth. Here at the Cape Cod Canal, the Army Corps of Engineers will ask for the 'deep draft' of a tug and barge combination...if the barge is light, the deep draft may be the tug. If the barge is loaded, the barge may have the deep draft. Controllers want to know that for clearance information.
73 and Good Hunting!
Gene N1EH
'The BigWingBoy'
Plymouth, Massachusetts, USA