| Show submarines UNCERTAIN those not well up in naval affairs have wondered why the submarine boat I 1 not made more use of in mccern warfare and why russia or japan failed to put them into action at port arthur or in the battle of the sea 0 japan the present imperfections are go great as to answer these question sir william white chief naval constructor of the british navy explains the unreliability of the submarine the great difficulty that confronts the inventor and constructor of submarines Is that of maintaining the vessel at any desired depth presume ing that the weight of one of these boats is exactly balanced by tho water it displaces it h in a state of equilibrium in which it may float at any given depth but any change in its weight even by the smallest amount means that it either risea at once to the surface or sinks rapidly to the bottom unless water ia admitted or expelled from tanks in the interior consequently care must be taken in the first place to prevent all sary changes in weight the most dangerous is the sudden yielding to outi side pressure of any part of the vessel A submarine completely immersed at a considerable depth has an enormous pressure acting upon it the bulging of a plate or two in an ordinary boat may be a trivial thing but the same accident to a submarine means an increase of weight relative to the water displaced and the danger of sinking to the bottom thos discharge of a torpedo the using up of fuel and other causes that affect the weight have also to be considered and compensated for danger of collapse under external pressure is overcome by the solidity of structure the quality of material used and the circular shape mke that of a cigar that Is adopted other difficulties are met by the use of tanks that can be rapidly filled or emptied care has to be exercised in the use of them that the weight ot the vessel shall be altered evenly SQ as not to make it lopsided or to produce change of trim but more important still tor the pur puri i pose of maintaining a desired depth is the use of horizontal rudders that will keep the boat submerged when traveling and bring it to the surface when it stops to use these the boat must be slightly lighter than the water it displaces having what may be called a deserve of buoyancy the reserve Is very trivial amounting to only pounds in vessels of tons weight generally speaking small as this margin is it suffices but a small chance in the density of the water would speedily wipe out this reserve and cause the vessel to sink if water were not immediately expelled from the tanks A vessel at the tilbury docks sank to the bottom rapidly when its reserve was withdrawn and there was great difficulty in raising it again in less than two seconds it was at the bottom of the dock the lower part of the boat being burled deep in the mud it took three quarters of an hour to get free and it looked as if it would never come up again |
