Tom Bowling. The ideal seaman. Immortalised in Dibden's song, and in Smollett's 'Roderick Random'.
Tom Cox's Traverse. Work done by a man who bustles about doing nothing. Usually amplified by adding 'pinning twice round the scuttle butt and once round the longboat'.
Tompion. Plug put in muzzle of gun to keep bore clean and watertight.
Tongue. Upper main piece of a built mast. 2. Rope spliced into upper part of a standing backstay. 3. Clapper of a bell.
Tonnage. Expression of a ship measurement that is not necessarily based on weight. In some cases it is derived from cubic capacity - this usage being ascribed to the number of 'tuns' that would stow in the space. The principal ship tonnages are Gross, Net, Displacement, Deadweight, and Under Deck tonnages.
Tonnage Deck. That deck that forms the upper boundary of the space measured when assessing tonnage. In vessels having less than three complete decks it is the upper deck. In all other cases it is the second deck from below.
Tonne. Metric unit of weight. Equals 0.9842 avoirdupois ton and 1000 kilo.
Tons Burden. Carrying capacity of a vessel expressed in tons. In Section 3 of Merchant Shipping Act it means 'net registered tonnage'.
Tons per Inch. Number of tons required to increase a vessel's draught by one inch at a given draught.
Top. Platform at head of lower mast. Rests on trestle trees and thwartship bearers. Gives a good spread to upper rigging. 2. Division of the watch in Royal Navy.