Within the period covered by this review, this eminent inventor has introduced an instrument which enables soundings to be taken while vessels are going at full speed, at depths of 100 fathoms and under. The sounding line adopted is a fine steel wire, such as is used by pianoforte makers, which passes through the water with very little resistance, and can be sent to the bottom by a light weight or sinker, even when the ship is going full speed. Fastened to a short length of rope, near the sinker, there is a brass tube, in which is placed a glass tube two feet long, closed at one end and open at the other. This glass tube is coated inside with chromate of silver. As the sinker goes down, the air in the tube becomes compressed, and sea water rises up inside, the height to which it rises depending on the depth, from the surface, to which the glass tube goes down. As the sea water rises in the tube, the salt of the water acts on the chromate of silver and changes the colour from red to white; thus a mark is left on the glass tube showing the height to which the sea water rises, from which the actual depth may be at once measured by a prepared scale. By means of this sounding machine a ship can feel her way round a coast in a fog without reducing speed. In later instruments the inventor has devised another form of automatic gauge, which obviates the use of glass tubes, and is a decided improvement on the gauge here described.
The well-known Improved Mariner’s Compass introduced by Sir W. Thomson enables the magnetism of the ship to be completely corrected instead of only approximately. This is attained by the use of several small needles instead of one or two large ones. The requisite steadiness of the compass card is obtained by means of an aluminium rim suspended round the edge of the card. The extreme lightness of the card reduces greatly the wear of the needle point supporting the compass. Along with the compass the inventor supplies an azimuth mirror which greatly facilitates observations either on a point of land or on a star, the whole invention proving from experience an almost indispensable item of outfit for well-appointed vessels.
The care and ingenuity expended on the question of ship safety must not, however, be measured simply by the amount of attention and skill exercised in constructing and outfitting vessels of the common type. The question has very naturally occasioned many distinct novelties in ship design. Some of these have been directly designed to secure safety, but the greater number have aimed at combining with safety the other qualities of speed and comfort; as in the instances given in the previous chapter. The success attained in practice, it need scarcely be said, has hitherto been but partial.
The problem of rendering ships absolutely unsinkable has, from very early times, received attention from many concerned in shipbuilding and navigation. Propositions and trials have been made from time to time, without as yet any very marked success attending any of them. Various plans have been submitted for safety-ships, the general principle of which consists in forming the ship into two or more distinct and entire portions, and in the event of one sustaining damage by collision or otherwise, those remaining to be disconnected and sent adrift—presumably with all passengers on board.
Other life-saving devices, while interfering somewhat with the original structure, have simply been intended to use or modify existing features or material on board ship. Two of these which have received attention from the Scientific Societies may be shortly described as examples of the class of devices referred to. One was the proposition of Mr Jolly, M.A., of the Royal Navy, laid before the Institution of Naval Architects in 1874; the other being that of Mr Gadd, submitted to the Manchester Mechanical Society in 1879. Mr Jolly’s proposal was to construct what he felicitously termed the “ark saloon,” an erection on the upper deck, and resembling very closely an ordinary deck-house, but instead of being built permanently on the vessel, it was to be an independent structure capable of being readily disconnected, and “while answering all the purposes of accommodation found in ordinary deck-houses, to have within it hidden resources capable of converting it when afloat into a perfectly navigable vessel.” Mr Gadd’s proposal was to form the upper portion of the bulwarks of ships of loose sections 12-ft. long, composed chiefly of hollow, thin metallic tubes. These sections when immersed in the water would form so many pontoons, and would be provided with cords and loops along their sides, and in the event of the ship going down would be lifted out of their place by the action of the water. Objections on economical grounds to Mr Jolly’s scheme, fully pointed out by members of the Institute, apply almost equally to the proposal of Mr Gadd. The expense involved in their application would far outbalance in the eyes of the shipowner the possible service they could render. No provision was made by Mr Jolly for launching his ark saloon, thereby limiting its use to cases of foundering; and even in event of this, the “ark” was only to be so in name until the good ship should “go under,” and leave the saloon serenely floating—presumably with all souls inside. The difficulty in Mr Gadd’s proposal, of at once making the bulwarks easily floatable and structurally efficient for the resistance of heavy seas, seriously detracted from its feasibility.
It would be a somewhat heavy task to make adequate note of all the varied proposals and patented inventions for the preservation of life at sea. Some of these, as in the foregoing instances, are proposals affecting structural features; but others, and by far the most numerous, are simply adjuncts to the vessel. Ingenuity has been specially directed of late towards bringing into efficient requisition, in event of impending shipwreck, the commonest items of a ship’s outfit. This has been abundantly evidenced in the several naval exhibitions held within the past three years in various parts of the country. Firms whose work lies in cork and Indiarubber manufactures have there exhibited in great profusion various forms of life-belts, life-buoys, life-saving mattresses and pillows, and life-saving dresses. Others, availing themselves of larger items, have shown life-saving adaptations of deck-seats, deck-houses, and bulwarks made into the form of life-rafts. Not a few of these devices have received adoption in our passenger-carrying steamships, and their more general use—especially if accompanied by proper knowledge of how they may best be taken advantage of—would materially help to rob shipwreck of some of its terrors at least, if not of its dire fatalities. It has been urged in this connection—and the plea is eminently reasonable—that Parliament should invest the Board of Trade with proper powers—if that Body is not already vested with all that is requisite—to take the matter of life-saving appliances thoroughly and practically in hand, and by means of experiments in all kinds of weather to determine which are the best means of saving life under different conditions. Having done this, also to draw up rules for the proper stowage and use of such appliances on board ship, and to see that such rules are strictly observed, and that no vessel be permitted to go to sea which is not so equipped.
The development in the size of steamships not only affects the quality of safety, but also in various ways the element of comfort at sea. The greater length, for instance, is calculated to neutralise the longitudinal oscillation, the effects of which are so often fatal to the comfort of passengers. Again, the great length affords an advantage in the way of allowing better state-room accommodation; all the rooms, or a larger proportion of them, being next the vessel’s side, and consequently more airy and better lighted. It is not, however, in the increased length so much as in the development of all three dimensions, and especially in the increased ratio of breadth to length, that modern types of steamships are enhanced in the qualities of safety and comfort. Mistaken or imperfect notions as to the ratio most desirable for speed, have kept in perpetuity types of steamers which the fuller light of modern scientific investigation has shown to be undesirable. Great beam is now believed to be not incompatible with great speed, and even apart from questions of speed the advantages accruing from breadth are better appreciated.