BOLTS in a ship, are iron pins, of which there are several sorts, according to their different make and uses. Such are, drive bolts, used to drive out others ; ray bolts, with jags or barbs on each side to keep them from flying out of their holes ; clench bolts, which are clenched with rivetting hammers ; forelock bolts, which have at the end a forelock of iron driv en in, to keep them from starting back set bolts, used for forcing the planks and bringing them close together ; fend or fender bolts, made with long and thick heads, and struck into the uttermost bends of the ship, to save her sides from bruises ; and rings bolts, used for bring ing to of the planks, and those parts whereto are fastened the breeches and tackles of the guns.
There are various inventions for driv ing bolts into ships, and others for draw ing them out ; we shall describe one by Mr. It. Phillips, for driving copper bolts into ships, for which he received the gold medal from the Society of Arts, &c. in the Adelphi. The instrument employed for driving the bolts consists of a hollow tube, formed from separated pieces of cast iron, which are placed upon the heads of each other, and firmly held thereto by iron cir cles or rings over the joints of the tube : the lowest ring is pointed, to keep the tube steady upon the wood ; the bolt, be ing entered into the end of the hole bored in the wood of the ship, and completely covered by the iron tube, is driven for wards within the cylinder by an iron or steel punch placed against the head of the bolt, which punch is struck by a mall; and as the bolt goes farther into the wood, part of the tube is unscrewed and taken oil; till the bolt is driven home into its place up to the head.
The tubes are about five inches in cir cumference, and will admit a bolt of seven eighths of an inch in diameter References to Plate, Life Boat:, Eec.
Fig. 4. A, the copper bolt, with one end entered in to the wood previous to fix ing the tube.
B, a piece of timber or ship's side into which the bolt is intended to be driven.
Fig. 5. C, C, C, C, the parts of the iron tube fastened together, ready to be put on the bolt A.