A floating mark to point out the position of objects beneath the water, as shoals, anchors, etc.; also any light body used to support in the water another body, whose specific gravity exceeds that of water, as the buoys used to support the swivel rings of mooring chains, etc The buoys used to mark the position of shoals, and to point out the right channel, are generally large and strong conical casks, made water tight, and are retained in their proper situation by a rope from the apex, made fast to an anchor dropped in the desired spot. These buoys are variously distinguished, either by their colour, or numbers painted on them; also sometimes by small beacons rising from their upper surface. All these buoys are under the superintendence of the Corporation of the Trinity House. Ships' buoys are generally formed as double cones attached at their bases, and are mostly composed of wood; but these being very liable to sink by leakage, buoys made of plate iron have for some time past been extensively used both in the royal and mercantile navy.
They are attached by ropes, termed buoy-ropes, to the anchor, care being taken that the length of the buoy-rope exceeds the depth of water in which the ship is to anchor.
A buoy intended to support persons who have fallen into the water, until a boat can be dispatched to their assistance. The forms and materials of which life buoys are composed are very numerous. The annexed cut represents a very simple and effectual machine of this kind invented by Mr. Scheffer. Fig. 1 is the machine inflated with air. It is made of skins, without any seam, (by a process of which the inventor retains the secret,) and is perfectly air and water tight; it is provided with an ingeniously contrived stop-cock, which screws into the hole shown in the engraving, by means of which the machine may be readily inflated by blowing with the mouth, and its escape afterwards rendered impossible. The buoyancy of the machine is suffi cient to support two persons; so that a man equipped with one, even if totally unacquainted with swimming, need not hesitate to proceed to the assistance of a person struggling in the water; and it is put on in a moment, by merely stepping into it, and passing it up to the chest, where it may be worn without inconvenience, or in the least impeding the full action of the limbs.
The following cut represents the air cock, a is the nozzle of the cock, which is screwed into the elastic air vessel; b an ivory pipe screwed into the barrel, used, when required, as a mouth-piece to inflate the vessel; when that is effected, the handle d of the plug is turned, so that the hole e of the plug is brought round opposite to the bolt f, when the spiral spring g projects the bolt into e, and locks it fast. The hole e is perforated through the plug, so that the locking takes place whether the plug be turned to the right or to the left: thus the cock is secured from being opened by accident, and the escape of the air is prevented. To open the air passage it is necessary to draw and hold back the spring-bolt with one hand, while the other turns the handle d into the position shown. Another important purpose to which these buoys may be applied is that of floating a rope from a stranded ship, by which means a communication with the shore is more easily established than when it is attempted to convey a rope from the shore to the ship, as the wind and sea assist in the transmission of the rope in the first case, whilst in the latter, they form a serious obstacle to it.
Spars and casks are sometimes employed to float the rope, but are much inferior to the present invention, as the lives of the men passing along the floating line are greatly endangered by their being struck with them. The weight of such apparatus likewise keeps the floats deep in the water, consequently less exposed to the action of the wind, so that the tide may carry the rope in a wrong direction; but with Scheffer's buoyant vessels lying on the surface of the sea, the wind would have so powerful an effect as to render the course of the tide immaterial; the passengers and crew might then with security pass along the rope to the shore, a the air vessel, or float for the rope b, which is suspended by the rings to the bands ccc; d d the water line, or depth at which it lies immersed when the rope is attached.
A most admirable life buoy, for the preservation of men who may have the misfortune to fall overboard at sea, by day or night, has been invented by Lieut. Cook, R.N. and is so much approved, that the lords of the Admiralty have given orders that every ship in the royal navy shall be fitted with one. The buoy is so fitted to the stern or quarter of the ship, that in the event of an accident by night, it can be detached from its position into the water in about ten seconds, with a fusee at the head of the staff, giving a brilliant fight, which a sea passing over it cannot extinguish. Ships may on these occasions frequently have to run a mile before they can sufficiently shorten sail so as to heave to with safety; but the buoy having fallen close to the man, the light blazing above his head will direct the boat to the spot without loss of time: this is a most valuable feature in the invention, invaluable, as from the great difficulty of finding a man in the water in a dark night, under these circumstances, men have been left to perish when there has been every reason to conclude that they had reached whatever might have been thrown to their assistance.
The apparatus consists of two hollow copper spheres, connected together by a horizontal bar, through the middle of which is fixed, vertically, a strong staff, formed of a metallic tube; the upper extremity of this tube supports the fusee, and the lower portion contains the balance rod and weight, which drop out of the tube when the apparatus is released from the ship, and preserves it upright in the water; the fusee is lighted at the same instant by a gun lock. The above cut represents the life buoy suspended at the stem of a vessel. In many ships, the communication with the triggers for firing and for letting it go, is so contrived, that the man at the helm can detach it without quitting his post. The following cut represents the lifebuoy in use, with the fusee blazing over the head of the man, who is seen standing on the balance plate.