THE NEW ROCKET FOR SHIPWRECK SERVICE.

Hawke's Bay Times, Volume IX, Issue 471, 18 April 1867, Page 3

THE NEW ROCKET FOR SHIPWRECK SERVICE.

(From tbs Pall Mall Gazette, December 31.) , Some time about the close of the last con- i tury an artillery officer who had riien from i the ranks, Lieutenant Bell, conceived the S idea of establishing a communication be- ; tween a stranded vessel and the shore by ■ projecting from a mortar a shell filled with ] lead and having a “ deep sea line ’’ at- i tached. Experiments were made with the ; apparatus in 1791, before a committee oi i the Society for the Encouragement of Arts, i Manufactures, and Commerce. An account of these experiments, which were perfectly successful, is given in the “ Repository of Arts” for 1808. But in spite of this success Lieutenant Bell failed, from some cause or another, to give practical effect to his invention, or even to obtain for it any general notoriety. In 1811 a committee of artillery officer* was assembled at Woolwich to report on a similar though independent proposal of Captain Manby, and by this committee Lieutenant Bell’s claim to priority in the matter was distinctly and fully recognised. But the merit of having been the first usefully to apply the invention and to press it into the public service is undoubtedly due toj ' Captain Manby, with whose name, indeed,

the schema is generally too exclusively associated. In the year that we have named—lßll—the invention was formally adopted, and an address was moved in the House of Common*, praying that the Prince Kegent would be graciously pleased to order the apparatus to be stationed on different parts of the coast. This is the origin of our present system of communication with stranded vessels, which is now established at some 350 coastguard stations, and by means of which a very large number of lives are annually saved. What that system is, and how it ha* attained its present perfection, may have some interest now that the season of stormy winter nights and wrecks has once again fairly set in.

During the half century or more which has elapsed since the subject was first mooted, the attention of a number of inventors has been anxiously directed towards the possible improvement of the means of effecting a communication of th ' kind in question, and all sorts of ingenious contrivances have been proposed. Colonel Delvigne employed for the purpose a howitzer instead of a mortar, thereby reducing the angle of fire, and in consequence the length of line to be carried, and he enclosed a portion of the line within the projectile. Captain Jerningham proposed an anchor of a peculiar form, as a means of hauling a lifeboat through a surf. Mr Greener and Mr Trengrouse each used a rocket to carry the line, the former discharging his rocket from a light harpoon gun, the latter making use of a small, and therefore comparatively feeble, “signal” rocket. Lieutenant Nares suggested the employment of a kite, and kites are manufactured for the purpose by the Shipwrecked Mariners’ Society, at London Bridge. A kite is open to the obvious objection that it can only be useful for conveying a lin efrom a ship on a lee shore to the land, and as in the confusion and sudden excitement of a wreck the kite would not often be forthcoming in working order, the proposition is scarcely practi cable. Other plans have been suggested, such as an arrow, and a had and line. But the advantages presented by rockets oyer other means of establishing acommu(nication were so conspicuous as to induce jMr Carte and Mr Dennett to prosecute jexperiments with a view to the employment of very much more powerful rockets than those which had been used by TrenIgrouse. The Carte and Dennet rockets were congrevo or war rockets with lines attached, and differed from one another mainly or only in the position of the slick. Some ton or eleven years ago Dennett’s rocket apparatus was formally adopted, and 9-pounder rockets of his construction, having a mean range of about 250 or 260 yards, weie issued to various coastguard stations, and a code of rules for their employment was officially established. During this period the gradual supercession of the Manby shot has proceeded, though some are still to be found at a few stations, and they are even occasionally manufactured. During this period, too, the great superiority of rockets to shot, or indeed any other projectile, has been practically established. They are more portable, us also is the apparatus from which they are fired, a point of great importance when the uncertainty as to the exact spot on which a wreck may occur is considered ; they carry their own illuminating agent, and are thus independent of the fuses which are nects I sary to indicate the path of a shot tired on a dark night; they do not require so long a due as a shot projected at a high angle of elevation from a mortar; the nature and duration of the propelling force renders the line carried out by a rocket less liable to be broken than a line carried out by a shot: and finally, line rockets are more accurate than line shot, owing principally to the fact that the deflection caused by the action of the wind upon the line is in a great measure corrected by the well-known tendency of the rocket to fly up in the “wind’s eye.” The range attained by the Dennett rockets was, however, inconsiderable as compared with what was desired, and Mr Dennett designed a “ double rocket ” two rockets side by side, like a pair of horses in a carriage— by which the line would be borneto a greater distance. In 18(52 some experiments took place at Woolwich with Manby’s and Delvignc’s shot against Dennett’s rockets, single and double. “The result,” as we learn from the official report, “was a general conviction on the mind of everybody present, and shared by M. Delvigne, of the great superiority of the rockets over either of the other plans.” The Manby and Delvigne shot fired from mortars gave ranges of 200 and 185 yards respectively; the single rockets ranged 240 yards, and the double rockets 370 yards, “ with great steadiness of flight, and with less length and weight of line in proportion earned out than the mortars tired at 45 degrees.” A range of nearly 300 (yards was obtained wi h M. Delvigne’.shot from a howitzer, but the line broke three times.

Mr Dennett’s double rockets were open to the objections that simultaneous ignition of both rockets could not always be depended upon, and a per-centage of failures was the result; secondly, the strain thrown upon the line by the combined force of s pair of rockets was sometimes greater than it was calculated to stand, and fractures of the iiue not unfrequently took place. With regard to this last objection, it might be supposed that a simple remedy could be found in the employment of a thicker line; but as any increase in the thickness of line entails a corresponding loss of range, its strength is necessarily limited. The satisfaction of these two antagonistic conditions—the extension of the range and the employment at the

same time of a sufficiently strong line—is indeed one of the chief difficulties with which the inventor of a “ life-saving apparatus " has to contend. The problem appears to have been solved, and the objections to the Dennett double rochet system to have been overcome, in the rocket which has recently been definitely adopted by the Board of Trade. This rocket has been designed by Colonel Boxer; and its chief feature consists in the placing of one rocket in the front of the other, the two being contained in the same case, and forming, to all appearance, a single rocket. By tills arrangement when the first or hinder rocket is exhausted the front one becomes ignited, and, by bringing a fresh force to bear, extends the range to nearly double the distance obtainable by a single rocket. At the same time the strain upon the line is at no time greater than what would be due io the employment of a single rocket. In fact, the advantages of the double and single rocket systems are retained without the disadvantages of either ; and the problem of a long range with little chance of fracture of the line is satisfactorily solved, i'be range obtained with these rockets is from 370 to 400 yards. Their cost is little more than one-half that of the Dennett double rocket. The reports made by the different coastguard officers to whom the rockets were supplied, in the first instance, for experiment, were so favorable that they were last year formally adopted in supercession of Dennett's rocket, and are now being supplied at the late of about 3000 annually. This rocket is undergoing trial in Prance, and a rocket of similar construction, designed by Major General Konstantinoff, is employed for the same purpose in Russia.

The main object of line shot and rockets is to establish a communication between the shore and a stranded vessel, but the principle is evidently applicable to a variety of other purposes, such as throwing rafts or bridges across rivers in the absence of boats; throwing suspension bridges across ravines or mountain torrents for the passage of troops and maierid ; in naval matters, it might be useful in landing through a surf, laying out anchors, or taking a vessel in tow by casting a grapnel over a buoy fast to a line in heavy weather.