ON A SUBMARINE

New Zealand Mail, Issue 1717, 25 January 1905, Page 60

ON A SUBMARINE

Mr Herbert Russell gives a description in “Pearson’s” of a voyage on a submarine boat: —• “The contour of the hull is like nothing so much as a gigantic symmetrical fish. A very narrow level ridge of platform, scarcely worth dignifying by the name of deck, extends fore and aft for a length of about 40 feet. From the ends of this the hull tapers away rapidly. A minat-uro flagstaff rising out of the water, with a little salt-bleached square or red bunting fluttering from it, marks either hidden extremity of the submarine ; they are just 100 feet apart. A single life-line, joining a row of breasthigh iron stanchions, is the only protection upon the slippery, sloppy platform. A trifle forward of amidships rises the conning-tower—a tapering, circular structure standing about a man’s height, with a row of little glass scuttles winking from the upper rim of it, a small collapsible bridge giving another three feet or so of elevation abaft, and the periscope tube rearing itself stalk-like from the fore edge of the tower. Aft, just where the hull becomes awash, a stout trunk of curved pipe spans some three feet of water with its arc; this is the exhaust for the petrol fumes.” The lieutenant in command now has orders to find his ‘first day’s trim’—that is, the minimum degree of buoyancy in which the vessel will float awash. The first day’s trim is always picked up m a stationary position:— “Inch by inch the water steals up the lavender walls of the conning-tower. Then the boat begins to pause in her descent as though hesitating whether she should go any deeper. This, m truth., is just what the lieutenant, bottled up under your feet, is considering. Not only is he concentrating his attention upon the gauge that will show him when the submarine has reached the vanishing point of buoyancy, hut he is also closely watching the clinometer to see that the vessel is sinking upon an even keel. A little too much depression forward must be rectified by letting a greater volume of water into the trimming tank aft, or vice versa. A horizontal poise is as necessary as the fine limitation of buoyancy to a submarine’s diving state.” Ere this all the standing gear on deck —'the collapsible bridge, life-line, flagstaff, etc. —have been struck. Before sinking, the crew blow out the compensating tanks, causing the boat to rise again some few feet; this is a precaution to test the valves and pipes which is never neglected on a British submarine. Then everyone goes below. There is a sensation of helpless imprisonment. as the hatch is hermetically sealed, but this soon wears off:— “Our boat, like all the under-water craft of the British navy, is a submersible, and not, strictly speaking, submarine. The distinction is well-defined. The submarine sinks through the exhaustion of all its buoyancy; she will go to the bottom like a stone. The submersibles on the Holland principle are forced up against their will, so to express it. Their surface buoyancy is reduced almost to the vanishing pouit, and they ire then steered dawn wards by means of their diving rudders. The thrust of the

propeller blades accomplishes and main* tains a state of submersion ; once stop tiie engines, and the boat will rise to the awash stage again, as determined by the finding of her diving trim. Of course, the submersible may be employed as a submarine pure and simple by admitting water enough into her tanka to carry her down, but the objection to this is the great difficulty of finding what may be termed a sinking mean.” Th ree hours is the submerged limit of a British submarine, though there is sufficient compressed air to last for six. Tlie effective range of their torpedo, with gju’osoope attached, is a mile ; they have sufficient petrol for a run of 350 miles, and their actual submerged speed is a little over 12 knots. The depth to which these boats can descend is only limited by strategic exigencies. If all their tanks were flooded they would sink 50 fathoms, although the interior walls would be sweating in streams under the pressure.