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

By this principle it is easy to conceive how a ship is compelled to turn into any direction, by the force of the wind acting upon her sails, in horizontal lines. For the sails may be so arranged as to receive the current of air, either directly, or more or less obliquely: hence the motion communicated to the sails must of necessity conspire with that of the wind upon their surfaces. To make the ship tack, or turn round with her head to the windward, it is therefore necessary, after she has received the first impression from the helm, that the head-sails should be so disposed as to diminish the effort of the wind, in the first instant of her motion, and that the whole force of the wind should be exerted on the after-sails, which operating on the ship’s stern, carries it round like a weather-cock. But since the action of the after-sails, to turn the ship, will unavoidably cease when her head points to the windward, it then becomes necessary to use the head-sails, to prevent her from falling-off, and returning to her former situation. These are accordingly laid aback on the lee-side, to push the vessel’s fore-part towards the opposite side, till she has fallen into the line of her course thereon, and fixed her sails to conform with that situation.

It has been observed above, that the first effort to turn the ship in tacking is communicated by the helm, which is then put to the lee-side. This circumstance being announced by the pilot, or commanding-officer, who then calls out, Helm’s a-lee! the head-sails are immediately made to shiver in the wind, by casting loose their sheets, or bowlines. The pilot then calls, Up tacks and sheets! which is executed by loosening all the ropes which confine the corners of the lower sails, in order that they may be more readily shifted to the other side. When the ship has turned her head directly to windward, as in d, fig. 2. plate [XI]. the pilot gives the order to turn about the sails on the main and mizen masts, by the exclamation, Haul main-sail, haul! the bowlines and braces are then instantly cast off on one side, and as expeditiously drawn in on the other side, so as to wheel the yards about their masts: the lower corner of the main-sail is, by means of its tack, pulled down to its station at the chestree; and all the after-sails are, at the same time, adjusted to stand upon the other board. Finally, when the ship has fallen off five or six points, as h, fig. 2. plate [XI]. the pilot cries, Haul of all! or, Let go, and haul! the sails on the fore-mast are wheeled about by their braces: and as the ship has then a tendency to fall off, she is checked by the effort of the helm, which for that purpose is put hard a-lee. The fore-tack, or the lower corner of the fore-sail, being fixed in its place, the bowlines are hauled; and the other sails, which have been neglected in the hurry of tacking, are properly arranged to the wind, which exercise is called trimming the sails. See Lee-way and Sailing.

TACKLE, palan, pronounced taicle, a machine formed by the communication of a rope with an assemblage of blocks, and known in mechanics by the name of pulley.

Tackles are used in a ship to raise, remove, or secure weighty bodies; to support the masts; or to extend the sails and rigging. They are either moveable, as communicating with a runner; or fixed, as being hooked in an immoveable station; and they are more or less complicated, in proportion to the effects which they are intended to produce.

If a b d e, fig. 3. plate [XI] be a single block, upon which are suspended the weights f g, then since the nearest distance of the ropes f g, from the center of motion c, are a c equal to d c, the block will be reduced to the lever or balance a d with respect to its power: Since a c is then equal to d c, it is apparent that f g will always be in equilibrium. As no advantage therefore can be acquired, in raising a weight by an immoveable single block, it is only rendered useful by changing the direction of the moving power. This circumstance is extremely convenient to the labourers, and often absolutely necessary; particularly in raising bodies to a higher station; as from the hold to the upper decks, or from the deck to the masts or yards, &c. which would otherwise be difficult or impracticable to perform. See also the articles Block and Whip.

When a single block is moveable along with the body to which it is attached, fig. 4. plate [XI]. as the blocks of the brace-pendants, reef-tackle pendants, jiggers, &c. the momentum of the power is doubled; because it moves twice as fast as the weight, or body to which it is attached. For in the same time that any part of the rope f, moves upward from f to g, equal in length to the two equal ropes d and c, the block, and consequently the weight annexed, will be drawn through the space e h, whose length is equal to one of the ropes only.

When a tackle consists of two or more fixed and moveable blocks, wherein one rope communicates with the whole; if one end of the rope be fixed, as in fig. 5. 6. and 7. in order to proportion the weight to the resistance, the power applied must be to the weight, as one, to twice the number of sheaves in the moveable blocks: because, in the efforts of a tackle, the velocity of the moving power is, to the velocity of the rising or moving body, as twice the number of moveable sheaves to unity, as appears in fig. 5. which consists of one fixed block a, and another moveable as e. For since one rope operates on all the sheaves from g to f, the part at f, lying beyond the fixed block, and called the fall, cannot be drawn down and lengthened, unless the two parts d and c, on each side of the moveable block, be at the same time equally drawn up and shortened. Hence it is evident, that the part a f will be lengthened twice as much as either d or c is shortened, because whatever is taken from each of those parts is added to the length of a f; but the point f, to which the power is applied, descends as fast as a f is lengthened and the point e, to which the weight is fastened, ascends as fast as d or c is shortened. If therefore, a weight suspended at f, be to a weight suspended at e, as one to two, they will balance each other, as being in the reciprocal ratio of their velocities.

Whatever has been observed with regard to the tackles above mentioned, is equally applicable to all others, and is in the same manner demonstrable, viz. that the velocity with which the mechanical force moves, in raising a weight, is to the velocity wherewith the weight rises, as twice the number of moveable sheaves to unity.

A tackle wherein both the blocks are moveable, and communicate with a runner, is represented by fig. 10. plate [VIII]. That part of the tackle which is fixed to one of the blocks, &c. is called the standing part; all the rest are called running parts; and that whereon the men pull when employing the tackle, is called the fall. The application of the tackle to mechanical purposes is termed hoisting or bowssing. See those articles.

Ground Tackle. See Ground Tackle.