TESTS FOR BATTLESHIPS.

Taranaki Daily News, Volume LII, Issue 277, 31 December 1909, Page 4

TESTS FOR BATTLESHIPS.

A NOVEL SANK WHKJH HAS REVOLUTIONISED THE SHIPBUILDING WOULD. There is a very simple piece of apparatus which ha- revolutionised ship'building, and which it is believed will •play a prominent part in the formation of new types of aerial vessels. This is a simple, long, narrow tank. Whenever our Government decide to build a new Dreadnought (says a writer in Pearson's Weekly) a model of the projected vessel is made in paraffin wax. The model will be possibly 14ft long, and it undergoes a series of tests' in one of the experimental tanks mentioned. In the case of the Government ] the tank is at Portsmouth, its length being about 400 ft a-ad its width about ! *2oft.

Just ahovc the water is a bridge which runs up and down the tank on a I sort of miniature tramway, mis bridge I contains many very delicate instruments whicli record exactly how the inodel behaves as it is' tow'ed through the water at various speeds by the aid of the bridge. The inodel is usually "weighted with shot so as to correspond with varying loads, and also various depths of water. The experts in charge are thus able •.o determine the speed of the projected battleship, its buoyancy, and numerous other facts regarding its behaviour. At j once the weak spots arc detected, and the model is modified until it achieves the best results.

In the old day* it would have been necessary for the actual ship to .have been constructed, and then it might possibly have been discovered that she was not of a suitable form to get the best results. By means of a simple tank the country is saved many thousands, probably millions, of pounds whicli otherwise would have to have been spent 'before the defects were discovered.

The use of the experimental basin has spread from this country all over the world, with the result tnat of recent years the forms of steamships 'have been greatly improved. Shipbuilders have discovered by its use that steamers require lines quite different from those of sailing vessels, and that a great portion of the engine power might be wasted by tlte boat not being of a proper shape. The most highly trained expert ■ provide designs anywhere equal to g .. ~e worked out as a result of tank experiments. By the use of the tank there is a guarantee that the huge sums spent on building vessels will not be wasted. Tank tests frequently have shown how a vessel's speed might be wonderfully increased by exceedingly small alterations. Not only is this so, but the tank shows at once what especial form of screw is' required in order to obtain the greatest efficiency from the propeller. More than this, the tank actually will determine the amount of damage a warship can sustain without sinking, Whether this is inflicted by projectiles, jan explosion of a tornedo in the ship's vitals, by ramming, and what not. in this case the model is constructed ot wood; that is to say, a model is man. to just beyond the water line. This tiny ship contains a number ot removable wooden blocks so shaped a» j to represent the ship's water-tight comI partmente. For instance, the blocks in [ the middle correspond with the com- ■ partments for the engines and boilers; I other blocks' represent the magazines, and so on.

, Now, if a water-tight compartment |>ere injured, naturally it would lill I with water; the method by which this [ is represented in the actual model is rc[markably simple. The wooden block which represents the compartment ■where the damage is supposed to have taken place is removed, and a piece ol lead is put in its place, the lead being in strict proportion to the weight 01 Ithe water which would fill the compartment. Naturally the model will sink in the •water, and will incline a special way. It can be seen how in this manner the experts can tell exactly how any damage would affect a big ship. The experiments are continued until the stability of the model is so affected as to show that the actual battleship would capsize.

This is the method which is now ap plied to ships, but it is believed that the experimental tank has a great future with regard to aerial vessels. Ai the present time experiments are being ■made ia.,tajil»i ffiHi..U>ia„and-in-vJew. .