Additional weight carried in a ship to give it stability and/or to provide a satisfactory trim. Nowadays this is done by pumping water in or out of trimming tanks, but in the past ballast was usually in the form of pigs of soft iron, known as kentledge, or stone or shingle was taken on board temporarily and stowed in the holds. Ballast tanks are the external or internal tanks fitted in submarines to control them when surfacing or diving. In ballast, the condition of a cargo vessel which has discharged its cargo and has taken ballast on board. Yachts carry their ballast externally, as a keel. Sailing vessels insufficiently ballasted were said to be crank.
Subjects: Maritime History — Warfare and Defence.