An Universal Dictionary of the Marine / Or, a Copious Explanation of the Technical Terms and Phrases Employed in the Construction, Equipment, Furniture, Machinery, Movements, and Military Operations of a Ship. Illustrated With Variety of Original Designs of Shipping, in Different Situations; Together With Separate Views of Their Masts, Sails, Yards, and Rigging. to Which Is Annexed, a Translation of the French Sea-terms and Phrases, Collected from the Works of Mess. Du Hamel, Aubin, Saverien, &c.

by William Falconer

Moorings are usually an assemblage of anchors, chains, and bridles, laid athwart the bottom of a river, or haven, to ride the shipping contained therein.

The anchors, employed on this occasion, have rarely more than one fluke, which is sunk in the river near low-water mark. Two anchors, being fixed in this manner, on the opposite sides of the river, are furnished with a chain, extending across from one to the other. In the middle of the chain is a large square link, whose lower end terminates in a swivel, which turns round in the chain as about an axis, whenever the ship veers about with the change of the tide. To this swivel-link are attached the bridles, which are short pieces of cable, well served, whose upper ends are drawn into the ship, at the mooring-ports, and afterwards fastened to the masts, or cable-bits.

A great number of moorings, of this sort, are fixed in the royal ports, or the harbours adjacent to the king’s dock-yards, as Deptford, Chatham, Portsmouth, Plymouth, &c.

MORTAR, a piece of artillery, shorter and wider than the cannon, and having a chamber different from the size of its bore.

Mortars are used in the attack of a fortified place, by sea, to discharge bombs or carcases amongst the buildings. The bomb is a great hollow ball, filled with powder, which, falling into the works of a fortification, &c. destroys the most substantial buildings by its weight; and, bursting asunder, creates the greatest disorder and mischief by its splinters.

The chambers of mortars are extremely different in their figures, and each of those figures is defended by better or worse arguments. Thus they are spherical, cylindrical, conical, bottled, or concave. In reality, nothing appears to be less determined upon true principles or experiments than the proportions of the several parts of a mortar[^[39]].

As the sea-mortars, or those which are fixed in the bomb-vessels, are generally fixed at a much greater distance than is ever required ashore, they are made somewhat longer, and much heavier, than the land-mortars.

Plate [VI]. fig. 7. represents a sea-mortar, the principal parts of which are, A, the chace; B, the reinforce; C, the breech; and D, the trunnions. The interior part, comprehended between the dotted lines, is called the bore, wherein the bomb is lodged; and the inner part of the bore, which is diminished towards the breech, and contains the powder, is termed the chamber.

Mr. Muller, in his Treatise of Artillery, very justly observes, that the breech of our 13 inch sea-mortars is loaded with an unnecessary weight of metal. The chamber thereof contains 32 pounds of powder, and at the same time they are never charged with more than 12 or 15 pounds, by the most expert officers, because the bomb-vessel is unable to bear the violent shock of their full charge. Thus the action of the powder is diminished by the vacancy left in the chamber, which is never above half filled. As a charge of 12 or 15 pounds of powder at most is therefore sufficient, it is evidently proved, by the theory of powder, that this will produce the greatest effect when discharged from a mortar with a cylindrical chamber, represented by fig. 8. He also proves, by a variety of experiments made by Captain Desaguliers and himself, that the conical chamber, now used, is considerably inferior to the cylindrical one with the last charge of powder.

To facilitate the use of the mortar, it is placed in a solid carriage of timber, called the bed, whose different parts are strongly bolted together. By means of this it is firmly secured in its situation, so that the explosion of the powder may not alter its direction. In the middle of the upper-side of this carriage, plate [VI]. fig. 9. are two semi-circular notches, to receive the trunnions; over these are fixed two very strong bands of iron, called the cap-squares, a, the middle of which is bent into a semi-circle, to embrace the trunnions, and keep them fast in the mortar-bed. The cap-squares are confined to the timber-work by strong pins of iron, called the eye-bolts, b, into whose upper ends are driven the keys, chained beneath them. On the fore-part of the bed a piece of timber is placed transversely, upon which rests the belly of the mortar, or that part which contains the chamber. The elevation of this piece, which is called the bed-bolster, is represented by fig. 13. and the plan by fig. 12. it is used to elevate and support the mortar whilst firing.