CONCRETE SHIPS.

Pukekohe & Waiuku Times, Volume 5, Issue 217, 13 October 1916, Page 4 (Supplement)

CONCRETE SHIPS.

LATEST METHODS OF CONSTRICTION. A cable .rcceved during the wceK described the launching or the firs! eoncrcte-built ship, a vessel of 3000 tons. It stated that the Swedish Minister for Marine was delighted with the result, and that he proposed to build ships of from 10,000 tons to ?0,000 tons of a similar material. Examples of this method of shipbuilding may be seen in Sydney, though here it haa been used only for ferry pontoons. Two of these pontoons were built under the supervision of tiw Harbour Trust about 18 months ago, and they are now in us© at the Milson's Point jetty and at the Xo. 6 jetty, Circular Quay. The larger oft he two is 127 ft. long, with a beam of 44ft.. a depth of 9ft., and a displacement of b9o tons. Both wero built at Glebe Island, and afterwards launched and floated into position. The pontoon at the Quay is supposed to be the largest of its kind in the world, and is also said to be practically unsinkable. The concrete is strongly reinforced with steel, and there are 31 watertight compartments Both pontoons have given complete satisfaction, and thoy are vastly more durable than those previously in use which were built of wood. The outsido wills are sm. thick. Pontoons of similar construction are in use in many other parts of the world, and it is als-j understood that concrete vessels have recently been built is Great Britain for the use of the Admiralty, so that i,l;» Swedish ship is not the first of its kin .1. The suggestion that presents itself to the lay mind is that a vessel built of such rigid material would be liable t j receive a fracture should it strike a serious obstruction, or a wharf, and would sink much more quickly than ■* wooden or iron vessel. The same objection, was, of course, raisej when nhips were first built of iron. The sted reinforcement of the concrete, however, prevents a fracture tpreadinw, and any injury would be of u local nature. An iron vessel which received a sunilar injury would sink just as quickly. In fact, in the case of the fern pontoons in use in Sydney, it is said that, short of blasting them to piero* w.'tli a powerful charge of explosjvi suitably distributed. it would take three hours to sink them. Experts consider that, with th.i launching of concrete-built ships ,-p. eently, a new era in shipbuilding has j been introduced.