an old ship of war, fitted with an apparatus to fix or take out the masts of his majesty's ships, as occasion requires.

The mast of this vessel is extremely high, and withal properly strengthened by sprouts and stays, in order to secure what are called the sheers, which serve, as the arm of a crane, to hoist out or in the masts of any ship lying alongside. The sheers are composed of several long masts, whose heels rest upon the side of the bulk, and having their heads declining outward from the perpendicular, so as to hang over the vessel whose masts are to be fixed or displaced. The tackles, which extend from the head of the mast to the sheer-heads, are intended to pull in the latter towards the mainhead, particularly when they are charged with the weight of a mast after it is raised out of any ship, which is performed by strong tackles depending from the sheer-heads. The effort of these tackles is produced by two capstans, fixed on the deck for this purpose.

Hulk, is also a name bestowed on any old vessel laid by as unfit for further service. It is probably derived from the ἀκαθάς, or vessels of burthen, of the ancient Grecians.