HISTORY OF MARINE ARCHITECTURE.

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sea, that the rudder has very little remaining power, being raised almost en-tirely out of the water. When the ship, in this situation, pressed on thelee-bow by the sea, and by the wind on the weather-quarter, rises to the top ofthe wave, it will fly, perhaps, to with such violence as to bring the head round ;and being laid, by this sudden attack, almost on its broadside, becomes immediatelyplunged, with the greatest velocity, into a tremendous sea, which breaking inwith irresistible force, will often sweep away whatever is upon the deck;the injury very commonly extending to the loss of the masts themselves,and the greater part of the people on deck, who are instantaneously pre-cipitated into the deep by the tremendous shock. It is, moreover, by no meansimprobable, but that the greater part of those ships whose fate now remainstotally unknown, have fallen victims to this species of disaster.

The use of sliding keels is known by actual experience to counteract allmischances and disasters of this kind. In fresh breezes, or in light winds, it istotally immaterial how much sail is set, or how it is disposed ; since the act ofraising or lowering the keels will immediately counteract the inconveniencethat might otherwise arise from carrying too much sail, either forward or aft.The most trifling practice will render the navigator perfectly acquainted with theiruse, and the easy steerage of his ship will convince him of their advantage. Ina gale of wind, it is necessary that the main and fore keels should be hauledclose up, and the stern keel let down to such depth as shall be found necessaryto make the vessel steer perfectly easy. The inventor expresses himself asabsolutely certain, that in case the very plain and simple instructions last givenare carefully followed, no misfortune, similar to that of broaching to, can everbefal a vessel furnished with sliding keels. “ How pleasing,” he observesin the latter part of this description, “ must be the reflection in the mindsof all persons on board, that they are strongly and unassailably guarded fromthe intervention of such an accident; but more especially how tranquil, undersuch a recollection, must be the mind of him to whom the safety of the ship,and the lives of the people on board, is committed ; whose memory may sufferfrom an accident, which neither his prudence nor his courage could foresee orprevent, and to which he himself falls the unfortunate unerring victim.”

To pursue the detail still further: vessels furnished with two or three slidingkeels will tack with far greater readiness than those which are destitute of them ;inasmuch as the fore and sternmost keels have each of them an effect on the ves-sel, very little inferior to that of the rudder itself. In working therefore to windward,

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