LIFEBOAT. A boat specially constructed for saving persons from wrecked or imperiled vessels, in storms or heavy seas, when the use of an ordinary open boat would be impossible or extremely dangerous. There have been countless contrivances for this purpose. all varying in their types; but unless a boat is provided with sonic distinctive properties, such as those of self-bail ing or self-righting, or both combined, it is not considered a lifeboat in the strict meaning of the term. The conventional open boat, with or with out air-chambers, which is used in broken water along the seashore for rescuing life, is known as a surf-hoat.
The no my supposed improvements that have been devised at one time or another for life boats, which have modified or departed from first principles, have generally resulted in no practical value, and there would be little ad vantage in considering . them here. Neither would it serve any profitable purpose to go fur ther back than the time of the origin of the present Eng lish model, even if that could be done with any of certainty. In 1755 Lionel Lukin. a coach-maker of an inland town near London. 'nit afloat on the Thames a Norway yaWl, which he had fitted with watertight compartments. a heavy iron keel, and other essen tials in buoyancy and stability, wide]] are the ear dinal and requisite feature-, of the life boat of to-day. Lukin did not sue eeed in bringing his invention, whieh had many defects, into par tieniar notice up to the time of his death. whirls oc curred in Is34. An expert boat builder of South Shields, Ilenry Greathead, however. put En kin's device into practical use as early as 1700. when lie produced a boat embodying the ele ments of the orig inal. but with a curved keel and the substitution of cork for side air chambers. T h boat had no means of freeing itself of water. or of righting in ease of being eapsizod. Janie; Bevelling. of Creat Yarmouth, was really the first person to project a self-righting lifeboat. which he did in IS5I. the design subsequently hi ing bet tered by dames l'eake, who added to it the self bailing quality. This boat has been much improved by study and experiment.
The chief rermirement of the English lifeboat is to counteract. as far as practicable, the ten denev of the boat to swamp when it ships a sea, and to remain bottom up when capsized. It
therefore must possess extra buoyancy, stability, self-bailing and self-righting qualities. Boats in general use are about 34 feet long and have an extreme breadth of S feet. The frames are made of white oak, and the outside planking of lbmduras mahogany, laid diagonally. To render the craft buoyant and insulnuergible, large air-tight boxes are built in at both ends, and copper air-eases are played tinder a water tight deck, and along the sides of the boat above the deck and beneath the thwarts. The dis charge of water is accomplished by means of 10 draining-tubes extending from the deck, which is on a level with the load waterline, to the bot tom of the boat, the top of each tube being fitted with a self-aeting valve, which opens dO•I1Ward when there is pressure from above and permits the water to flow out, but prevents it from en tering from the opposite direction. The water on the raised deck, hieing above the outside level of the sea, by the force of its own gravity passes through the valves into the relieving tubes and escapes. A heavy gnu-metal keel. three inches deep. is secured to the wooderi keel of the boat, and this, in conjunction with air-chambers, effects the self-righting property. The craft, when bottom up. floats unsteadily on the bow and stern compartments. while the keel, being carried above the centre of gravity. falls on one side or the other and drags the boat back to its natural, upright the water that has been shipped in the process passing out through the tubes. A lifeboat has usually five 1hwarts, which can accommodate 10 oarsmen, double banked. is fitted with a centreboard, and pro vided with movable masts and sails. Attached to the exterior sides are festooned life-lines, to which persons may cling until they can be got into the boat. Owing to its great weight. sonic 4000 or 5000 pounds, this lifeboat can only be used to advantage along steep shores or where it can be launched directly into deep water. It is very useful in going long distances in rough water under sail. When the boat is kept on shore a carriage is furnished for transporting and launching it, while portable roller skids are also supplied to aid, when required. in its con veyance over the ground. The equipments, which are very complete, are carefully stowed in the boat always ready for immediate service.