Ls December 1849 one of the South Shields life-boats upset alongside a wrecked vessel on the Herd Sand, on which occasion 20 out of 24 men who formed the crew of the boat, perished. This melancholy accident, which in one moment prematurely cut off so large a number of brave seamen, and carried desolation and misery into so many a household, was the immediate cause of the introduction of the self-righting life-boats. The Duke of NORTHUMBERLAND, as is generally known, shortly afterwards offered a prize of 100 guineas for the model or plan of a lifeboat which should possess in the greatest perfection those qualities which it was considered that such a boat ought to possess.

Amongst those qualities, the Committee appointed to define the various requirements, and to decide on the merits of the several plans, &c., of the different competitors, assigned a prominent place to that of selfrighting ; most justly and most fortunately so we conceive; as the result has been the introduction of a life-boat, which, in addition to qualities of the highest order in other respects, possesses that of self-righting.

In a paper on this subject in the 5th Number of this Journal, it is narrated that, Of 16 disasters to life-boats recorded in the Northumberland Report, 9 were caused by their upsetting and drifting on shore bottom up, involving a loss of 56 lives.

Surely such a fact was of itself sufficient evidence of the desirability of enabling lifeboats to self-right, provided they could be made to do so without sacrificing or impairing other qualities of still more importance.

Nevertheless there have not been wanting those who declaimed against the introduction of self-righting, and who have maintained that it cannot be obtained without sacrificing both stability and speed. Unfortunately accidents, accompanied with loss of life, occurred to three of the first self-righting life-boats that were built, which tended to foster prejudice against what was considered a dangerous innovation. Those accidents, however, were occasioned by %'causes quite independent of the self-righting power, chiefly from an imperfect mode of ballasting.

We believe we shall be able to show, not only that self-righting may be obtained without impairing any other desirable qualities, but that the very means which are employed to produce it increase the stability and speed of the boat, and afford increased shelter to her crew.

We at once concede that these two points, stability and speed, are of prior importance to self-righting ; without the first ["a [boat would not be safe in a heavy sea, and would be constantly liable to upset, whilst without the second all her other good qualities would be useless, since she could not be transported against a heavy sea and gale of wind to the assistance of a wrecked crew. If, however, it can be shown that a boat can be made to self-right without reducing either her stability or speed, we maintain that it is the duty of all who provide life-boats to furnish those who man them with this additional security to their lives.

1st. As regards stability. GREATHEAD and the earlier designers of life-boats appear to have considered that stability was only to be obtained by great breadth of beam ; and accordingly we find that the beam of their boats was generally one-third at least of their length, which is about the proportion of length and breadth which is possessed by the Shields and other north country lifeboats at the present day. A few of these boats have also water ballast, but for the most part they have none. Now great breadth of beam is unquestionably unfavourable to self-righting, as it is also to speed, and the beam in the self-righting boats has accordingly been reduced to about onefourth of their length; but by building them with a very flat floor, and by giving them heavy iron keels, their stability is made equal, or more than equal, to that of the older and wider boats, whilst their speed is necessarily greater.

In illustration of the great stability which may be obtained with the reduced beam, we may mention that a life-boat with 30 feet length and 7-J feet beam, such as those now built by the National Life-boat Institution, will bear the weight of 24 men standing on one gunwale only, without forcing it under water.

A further reason for want of stability in these boats, apart from breadth of beam, has been advanced ; in order to the comprehension of which it will be necessary shortly to explain the principle on which the selfrighting capacity is obtained. The object desired is to establish what in mechanics is termed an "unstable equilibrium," or, in vulgar phrase, make the boat " top heavy," when keel up. This is effected, Istly, by giving considerable sheer of gunwale and enclosing the space at the extremities of the boat, to 3 or 4 feet from the stem and stern posts, so as to form water-tight compartments, or tanks, as they are called, on which the boat will float when keel up; and, 2ndly, by adding an iron keel, or other weights placed as low in the boat or as near to the keel as practicable. Thus an unstable equilibrium is established when the boat is keel up; for floating on the two points of buoyancy at the extremities of the bow and stern, the slightest lateral motion or unequal distribution of weight within the boat brings the iron keel on one side of the centre of gravity, when its weight pressing downwards on that side, and the buoyant power of the enclosed ends lifting upwards on the other, speedily restores the boat to her original position.

The charge of reduced stability above referred to, which has been made by celebrated boat-builders, who have adopted a straight gunwale and low extremities to their life-boats, is, that the top-weight of .the raised extremities must, when the boat heels over, render her more crank than she otherwise would be.

To this we reply, that, up to a certain angle of heeling, such would be slightly the case, but that even to that point it would be more than counteracted by the weight of the heavy iron keel which forms one part of the selfrighting power: beyond that angle, however, i and before the boat was on her,beam-ends, I the bow and stern air tanks would begin to be immersed, when, owing to their greater height, and consequent greater distance from the iron keel, both they and it would act with greater power in resisting whatever force might be exerted to capsize the boat, inasmuch as they would each be resisting that force with a longer leverage than they would do if the sheer of the gunwale were less and they were brought closer together.

We have proved, therefore, that a boat's stability at the most dangerous moment, viz., when on her beam-ends, is increased by the self-righting power.

With regard to the second charge, that the speed of a life-boat is decreased by the self-righting power, we think that we can quite as successfully refute it as we have done that which affected stability.

1stly. As to the additional weight of the iron keel. Without doubt in calm weather and smooth Water, with the limited power obtainable by oars and men's arms, a light boat may be propelled faster than a heavy one; but exactly in proportion as the force of an adverse wind and the blows of a head sea are increased in amount and in power, in that proportion will the additional inertia derivable from weight tell in a boat's favour, husbanding and regulating the force which has been applied to the oars precisely as the fly-wheel does that of a steam-engine or other machine.

2ndly. As to height of extremities of bow and stern. If the bow be kept sharp to gunwale height, and if its height be not excessive, it is favourable to speed; for if the bow be low every heavy broken sea will break over it and fill or half fill the boat, which, rushing fore and aft within her, apart from the inconvenience or injury which it might occasion to her crew, would impede her progress through the water far more than the cloven exterior blow of the heaviest sea would do.

Perhaps some of the earlier life-boats built for this Institution on the self-righting principle (from Mr. PEAKE'S designs), had greater height of bow and stern than was necessary to secure their self-righting; in its later boats, however, it has been reduced to its minimum amount. Thus a boat 30 feet long and 7t feet wide, with 3 feet 8 inches depth amidships (inclusive of keel), has only 5 feet 4 inches height of bow and stern, or 1 foot 8 inches sheer of gunwale. Now this is not a greater height of bow and stern than every life-boat ought to have to keep the sea from breaking over it; and it therefore follows that the speed of a life-boat cannot be impeded by any height of ends which the self-righting principle calls for, any more than its stability is diminished thereby.

In addition, however, to the assertion that the self-righting power impairs the other qualities of a life-boat, it has been said that in nine cases out of ten, the crew could never avail themselves of it, as the wind and sea would beat a boat so quickly to leeward after self-righting, that those thrown out of her would not be able to swim fast enough to follow and get into her again. The validity of this charge can only be proved or disproved as time will develop; but on the only two occasions when the selfrighting boats of this Institution have upset, the crews have been enabled to get into them without difficulty, after their righting, and their lives have been thereby saved. An account of one of these instances, which occurred at Lyme Regis, will be found at page 124 of this Journal; the other occurred at Teignmouth in Devonshire, when the life-boat was upset by a heavy roller breaking on her broadside on the bar off the entrance of the harbour. This last-named boat is one of BEECHING'S ; but previous to this accident she had had some alterations made in her by the Shipwrecked Fishermen and Mariner's Society prior to her being transferred, with the other boats of that Society, to this Institution. Her crew, on that occasion, without difficulty, got into her again, although the coxswain nearly lost his life through having neglected to put on his life-belt.

In juxtaposition with these two instances, when the advantage of self-righting was so forcibly manifested, may be placed those of the Shields life-boat above alluded to; the Tug Steam Company's life-boat at Liverpool, which upset on the 18th of February, 1854 (vide Life-boat Journal, page 149), when 10 persons out of 11 were drowned ; and lastly, that of a life-boat at Spurn Point, at the north entrance of the Humber, so lately as the*19th of November last: this boat was upset when fastened by a towrope astertn of a stranded brig, there were only two men in her at the time, and both were drowned.

Had this boat been possessed of selfrighting power, who can say that both these poor fellows might not now be basking in the sunshine of life ? With so recent a warning sounding in our ears, we feel that we should have neglected a duty had we not endeavoured to call the attention of all proprietors of lifeboats to the subject and laid before them the explanation of the principles and advantages of the self-righting power, which, to the best of our ability, we have now attempted to do.