BOLT

Plate II

The bolts are principally employed either to unite several members of a ship's frame into one solid piece, or to fasten any moveable body on a particular occasion. Those which are calculated for the former purpose have commonly small round heads, somewhat slatted, on the contrary, the bolts which are intended for the latter use, have either a large round head, as those of the chains, fig. I. plate II. or an eye, with or without a ring in the same place, fig. 3. and 39, as those which are designed to secure the great guns, the jears of the main-sail and fore-sail, the stoppers of the cables, &c.

The bolts are short or long, according to the thickness of the timber wherein they are to be lodged: they penetrate either quite through the pieces into which they are driven, or to a certain determinate depth. The last of these, called a rag-bolt, is retained in it's situation by means of several barbs, fig. 2. which, fastening into the timbers, prevent the bolt from loosening from it's situation by the working of the ship. The first, after being driven through the pieces it is intended to unite, is confined by a flat iron wedge, called the forelock, which is thrust through a narrow hole in the small end of the bolt, where it is hardened home by a hammer; and to prevent the forelock from cutting the wood-work in this position, a little iron ring is fixed over the end of the bolt, between the forelock and the timber.

Those bolts, which have the largest of the round-heads, are called fender-bolts, being driven into the wales, stem, or sides of some small vessels of burthen, as lighters, beancods, prames, &c. to defend their timber-work, from the shock of any other vessels which may fall aboard by accident.

Reference Works