UNSINKABLE SHIPS.

North Otago Times, Volume CVI, Issue 13982, 19 November 1917, Page 8

UNSINKABLE SHIPS.

LESSONS FROM THE "GREAT! ' EASTERN."' ','"' v THE PROBLEM OF BULKHEADS. • The absolutely unsinkable ship is possible only if we deprive it of all its usefulness, unless, indeeed, it is packed tightly with.an linsiiiknblc cargo-ami thru it Is the contents, not tho ship itself, that prevents its going to the bottom. Every ship nowadays is'built of materials that arc- heavier than water. Vessels arc kept afloat by the exclusion of the water from the spaces within the- hull devoted io the accommodation of passengers or freight. If Hie water is admitted to these, the vessel inevitably troes' down. We can no.-t----pone tho sinking by making theso spaces as small as possible and separating them as completely as we can, but ovon then the ship can ln> sunk if an enemy possesses the means to sink it. It is. somewhat strange,'under. these circumstances, says a writer in the engineering supplement of "Tho Times" lo liinl that iiiifny people continue to put forward all kinds of prqposals for rendering- ships unsinkable. "A ship," lie says, "will always remain a lion t provided she lias reserve of buoyancy —that is lo say, so long as the weight of water that would be displaced by the total volatile of the ship is greater than her weight. It will help 'matters to -consider two extreme eases, If 'a solid homogeneous log is just floating" in'.water, it stands to reason that any piivf or parts of it can be destroyed without the remainder sinking. On the other hand, if an empty shell is just afloat in the water, any break in ,the shell, however small, will be sufficient to cause it to sink, A ship is neither a solid log nor an. empty shell, but is something between the two. A ship is a shell, inside of which arc all hinds of litt'nigs, such as the structural purls, .Ilie passenger equipment, and so on,-'

Tim writer devotes considerable spare In tins question. Tt is.possible so lo build the water-tight compartments, nl' a vessel that when water is admitted to ope of these, she will capsize, although .slie will not sink. This has not. infrequently happened.' '-'lt is safe to' say," the writer concludes, "that the' question of unsinkability of sliipH is closely connected with their stability, and that in, the future ships will be relatively wider than in the past." ! A-Possibility. On the other hand, an American ship-i building expert, J. Bernard Walker, as--' eerts that the ship is ; a possibility. Apparently his definition of the term is "difficult to sink" or "unlikoly to sink"; so ho is really not at serious odds with the Times expert. "Is it possible! to build an unsinkable ship? It certainly is; for over half a century ago Brunei produced in the Great Eastern a ship which was more entitled to bo called 'unsinkable' than any merchant ship which has been built from that time to this, Brunei was a technical genius ... The Great Eastern' was a magnificent ship, and she was built so well that, outside the Navy, there never has been a ship that could' compare with her for protection against sinking. So good was she that ,011 one of her early voyages to New York', she ran on the reefs at Montaulc. tearing a hole in her bottom ten feet wide by eighty; feet long, and yet steamed gafely down tho Sound, "anchored in Hempstead Harbour, and was there repaired by the caisson method without going ,into dry dock. . . From the date, 1858, to "the present time there has been a steady deterioration in the protective elements of merchant r-hips.-Brunei- built his famous liner on the 'safety-first' principal. Since that time the commercial man, who is rarely an .idealist, and' generally very much the, other way, has thrown out,' one by one, .those safety elements which Brunei Incorporated hi liis ship, until to-day the chance of a ship surviving a heavy collision'or the blow of a torpedo is about one in one hundred.

;,; "The navaicoustructors of the Uni-ted-States .Navy have worked but a system ~n(' ■eoiiist.riictioii 'involving! elaborately : sub-divided torpedo-defence f|»aires;-.n-liii'|i is so effective that they ,(ii'eVAvilliiig to'guarantee ami apply the Kystcm-'to merchant construction, They Wlievr that they can turn out merchant ships that would tie proof against sinking by^the torpedo. ... Wo°uave. given to this matter and submit, merely as- fl study, the an.cQiupanyhig ..: , : plan of a freighter /losigiujd' to pass through the submarine zone.^o^liegiii'with, we have omitted th& ; .'donbl('' sklii-this for the reason that both skins would lie btiiat in by: n.njodcni toi'|jedo and the inner'skin would ■■rnerely furiljsli an additibriali number of flying fragments)'to bq caiv tied tinder high velocitySi'n'to the'ship, Tiie principle-adopted is that of niiip.; wous carried lip tb"Hvcitppcr : or of tho ship,'| 'Avliij , Ji;,.'ilcek is .of- steel i'arid ';l)uiltj flibroiighly water-tight; .TligV transverse', Imlkheafliiig iytoulilKbir "loe'ated '■ vWy much closer fogether than 'the: 'present practice—2;) feet*apart- in vessels';of i 4000 tp 70(10 toils, the widths I ing: proportionately to the': increase in.:! :si.ze of.thVslnp;': :> : -. '■.: .It is'oiir'be-''

lief that a <dnp'builf along these with domlcs« bulkheads, mlh light h.itilie«, and \ent chambers that iroiili be lilonn o|»en, allowing the escape of 'the gaies, <ould withstand toipedo n< MeJ> pud lecenc one, and possibh ttfn, toip"<lops without neecssnnh eoing to tho bottom," j ' . ' i