SUBMARINE WARFARE.

Star (Christchurch), Issue 5273, 1 June 1895, Page 2

SUBMARINE WARFARE.

In 1864, during the American civil war, a submarine boat succeeded in sinking the Federal frigate Housatonic. This boat, however, waß hardly an unqualified sucoess, aa, running into the hole made by its torpedo, it went down witb the ship; and three crews had previously been lost while carrying ont its initial experiments. Since then, many methods of submersion have been tried, but it is only within the last five yeara that naval powers havo awakened to the fact that a submersible boat, though by no means so formidable for offensive purposes as its name at first leads one to believe, ia a factor which might have to be taken into consideration in tho next naval war.

THE MOBT MODEBN TYPES

of tbe3o boate are the Holland, Nordonfeldfc, Tuck and Goubet. The Holland boat comes to us from over the Atlantic, and is peculiar in itß weapon of offence. The latest type is fifty feet long, eight feet in diameter, and is driven by a petroleum engine carrying sufficient fuel for two days' run. The diving is effected by means of two horizontal rudders, one on each eide of tho stern. This only allows of submersion when the boat is in motion s and the boat cannot be horizontal while submerged. It carries ten-inch gelatine blasting shells, fired from a pneumatic gun, twenty feet long, whose radius of action is two hundred yards under water and one thousand yards abovo. The use of gelatine is also objectionable, as the confined space and th« vibration of the boat prevent such explosives being carried without some risk of premature explosion. It is for this reason that gun-cotton is adopted in torpedo work, as it will not explode on concussion, and is little affected by change of temperature. THS PRINCrPAIi FBATCRKS OF THK NOBDBNPELDT BOAT .ere its method of submersion and ita propulsion by steam. The latest type is one hundred and twenty-five feet long, twelve feet beam, and displaces two hundred and fifty tons when entirely submerged, one hundred and sixty tons when running on the surface. Her propelling machinery consists of two double cylinder compound engines, with a horse-power of one thousand, and propelling the boat at fifteen knots on the surface. The submersion of the boat is effected by meanß of two horizontal propellers working in wells at each end. Two conning towers project about two feet above the deck, of one-inch steel, Burmounted by glues douaos, protected with steel bars, for purposes of observation. The boat usually runs on the surface with these towers showing, unless the buoyancy, whioh is never less than half a ton, is overcome by the horizontal propeller**, when the boat becomes partially or totally submerged according to their speed. To asoend to the surface it is only necessary to stop the horizontal propellers, which also stop automatically on reaching a set depth. In the forward tower are the firing keys, machinery and valves necessary for driving or steering the vessel, for controlling the horizontal propellers, and for discharging the Whitehead torpedoes. Four of these are carried, and they are discharged with powder from two tubes in tho bows. In the conning tower are also placed the instruments indicating the depth, level and course. When tbe boat is awash, the funnels have to be unshipped and the boat closed up before submersion. The length of time, twenty-five minutes, required for this operation is an objection to this boat, though when submerged it does not get unpleasantly hot. The temperature after a three hours' submerged run waa only ninety degrees Fahrenheit. The crew consists of a captain and eight men. THB TUCK also comes from America. It is of iron, cigar-shaped, thirty feet long and six feet in diameter. It is submerged by means of a horizontal rudder in the stern and a horizontal propeller acting vertically ! amidships beneath the boat. It ie driven by electricity, supplied from storage batteries packed closely in the bows. Com- . pressed air is carried in reservoirs, but a supply is usually obtained when the boat is not far from the surface, by means of an iron pipe twenty feet long, which usually lies on deck, but which can be raised to an upright position by gearing > from within. The top then rises above the surface of the water, and by opening a valve in the foot and attaching a pump, fresh air is drawn into the interior. The crew need not exceed three men. THE GOUE2T CLASS are of iron, sixteen feet long, three feet wide and about six feet deep. The motivepower is a Siemens motor driven by storage batteries. Fifty of these boats were purchased by the Buseian Government. They have no rudder, but a universal joint in the screw shaft permits of the screw being moved through an arc of ninety degrees. The torpedo is carried outside the boat, secured by a catch worked from inside. Oa arriving under tho enemy, the torpedo

is released, and striking thoahip's bottom, is bold thora by spikes, flfce boat then withdraws, unreeling a ooncMting wiroi and when at a safe distanoe, i\__.. The The absesoo of a rudder, however, causes erratio steoriug, and the spikes with which tbe torpedo ie fitted might fail to stick in steel-bottomed ships. (Submarine boats cannot be driven nnder water at a speed exceeding six knots. If driven boyond, they are inclined to dive, and iu deep water, before tha corrective forces against a dive bave had time to act, might reach a depth whera the pressure would drive in the sidos or compress them to a sufficient extent to ssrlonsly reduce the displacement. In shallow water, the boat might be driven on to the bottom, and if it be olay, held there, an accident attended with fatal oonsequences in the case of one boat.

BUBMEBQID BOATS ABE USELESS,

It is also difficult to direct the course ot a submarine boat ; and it is doubtful whether the advantage of not being seen counteracts the disadvantage of not being able to see. Aocording to Mr Nordenfeldt in a lecture (E.U.S. Institution, 1886, No. 133) on Submarine Boats, " The mirror of the surface throws a strong light into the boat ; you cannot eee forward at all, and you cannot Eee far astern ; it is as blaok as ink outside ; you can only see a sort of segment." This means that you cannot safely advance at a groat speed under water. It is impossible to think of a submarine boat as a boat that actually manoeuvres and does its work under water. The boat should run awash, and you can then see where you are. When we consider, then, that a boat totally submerged cannot be driven over six knots, and cannot be properly directed; when we consider the speeds of seventeen and eighteen knots attained by modern battleships, we arrive at the conclusion that boats totally submerged are useless against modern battleships in motion, Eunning awash, they 6ould be tackled by torpedo catchers and torpedo boats.