ALL ABOUT SUBMARINES.

New Zealand Herald, Volume LIV, Issue 16467, 17 February 1917, Page 2 (Supplement)

ALL ABOUT SUBMARINES.

SUBMERGED DEPTH, 300 FT. P' ■ ■' USE OF AIR-FILTERS. "•. 'Uhe submarine, is of particular interest ' just now. For submerged work the submarine is provided "with large storage batteries, which furnish energy sufficient to drive the boat from'lo to 11 knots or even faster in the latest type. There are two distinct conditions in commonly known as the surface condition, the boat is prepared for cruising. . A which the boat may bo used. In tho first, considerable portion of her hull is above water, a removable navigating bridge is in place, and she is driven by largo, powerful, internal-combustion engines. Under these conditions she is managed in about the same way as any vessel built to run upon the surface. The second distinct condition exists when the boat is submerged. To pass from the surface to the submerged condition certain valves in tho interior of the boat axe opened. This allows the water from tho sea to run into great tanks built within the boat, and thus virtually sink her. These tanks are closely gauged, 60 that just the required amount of water is taken in. > Under norma! conditions, when the boat is at rest with tho ballast-tanks fiilod, she will have a few hundred pounds reserve buoyancy, which is represented by the top of her conning-tower protruding above the water. If desired, this ouoyancy may be entirely destroyed by admitting a small additional amount of water, equal in volume to the volume of that part of the conning-tower above water. The amount of air originally contained within the bull is sufficient to support life with comfort for at least 24 hours. But, in addition to the air thus contained, the boat carries a largo supply.; of compressed air in steel flasks, which, if used for breathing purposes, would be sufficient for a number of day* _. Submerged. After having brought the boat to the 6ubmerged condition in the manner above described, powerful electric motors are started by throwing in a switch. These motors derive their energy from storage batteries contained in the boat, and drive the propellers. The same storage batteries furnish current for" numerous auxiliary motors used for pumping, steering, hand- >■'. ling torpedoes, etc." t vi ** r . , ' " The motion of the boat when wider way is controlled by two sets of rudders; one of these sets, known as the vertical rudders, directs the boat's course to port or starboard fust as does the rudder of an ordinary ship. i In addition, there are v; provided horizontal rudders, which &;rve )?]to control the motion of ' the boat in a, .- horizontal plane; that Is to say, the depth •'at which sne runs is regulated by_ these . rudders,;, For . steering in the horizontal plane instruments , are provided, 80; that the boat may .be navigated with the same degree of. accuracy as i boats on the surface. ' ' ' - 1 ■ Of' course, submarines vary in type. ' Thus a typical submarine measures 120 ft in length, with a beam of idt, 2£in, arid a draught of 12ft Sin. The displacement on the ■ surface is 225 A tons, and ■r i when submerged 280 i 1 tons. The vessel is provided with two hulls.- The ; outer baa v ■ .'.the lines of a torpedo-boat, which, with the high- freeboard and superstructure, .serve to raider the boat extremely seac ' V fworthy. The inner > hull sis i divided j. into f 1 three longitudinal sections, being built up . of three circular welded sections bolted together. TTie hlccbSe-runner Deutschland, which is 'said to have been one' of the largest . submarines constructed by Germany/ and " ' which was more or less a cargo vessel, is about 300 ft long, With - a beam of 35ft and. Bf|§ draught of 17ft.- The speed surface of this - boat is ; from 12 to •13 knots, and whilst i submerged about seven knots. . The fight* in submarine,: to which this article refers, is that of which particulars are definitely known, but larger vessels have been con? v. - structed, of which details are not availV able. . > ■ 300 Feet Down. This shell is of sufficient strength to en- ',' able y the craft to withstand safely a water ■ J y ; pressure equivalent to a sea, depth of 2954 ft The space between the outer and ■- ' ' inner hulls is. subdivided J into a number , 'of * watertight compartments, which . con- . tribute greatly to tna safety of the vessel, since a number" of these may be punctured without " endangering floatability. -ft" The gM Y > water ballast, oil, and petrol tanks are • also carried in this space. _ .The - engine-room, containing J,he pro- || | - pelling and auxiliary machinery, is placed tpf®! aft, together with, a portion of the accumulator battery."" Surface 'v propulsions■ is , effected by two sets of four-cylinder, ver- " tical. petrol motors, developing an aggre- | S gate »of 440 horse-power, while when 'travelling submerged two electric motors | IV»V, developing - an-, aggregate ; 0f<260 i horse- - , v power are brought into service. . v : The : _ .! -capacity of the secondary^battery is tflO " I t kilowatt hours. Forward of ; the engine- " .. room are the internal water ballast tables, •and amidships - the in • - which are placed all. the devices for steering, diving, and controlling the boat. ' The. conning-tcwer- ; v built >up 'of light • plating, has a ship-shaped form, for the " purpose of minimising resistance when the craft is travelling submerged. In the v.. bow are the second section of the electrical " accumulators and the torpedo-tube room J and gear.' There are two torpedo-tubes .' carried in the bow, while en the deck, aft, • ' mounted on a bridge, is a third tube. "A 5 The ■ cxiving-rudders -. are c mounted ' in , • pairs; one on either side fore and aft, with an ordinary vertical rudder at the stern ; ' ; for lateral steering. ; ; Each motor set • drives a reversible propeller. The accomV ; modation for the navigating officers is in " the conning-tower,. while the quarters of -• . the crew of 10 men are in the doit, as is also the galley. ■> ' . j y ,;In the Lake types of the Germania class llgrf 0. of submarine • Diesel; engines, wing * heavy •> ■ oil in preference to the more'; volatil eand inflammable petrol, , are used.' - These ||f|| motors develop from 200 -to 220 horse-//..-power.. For under-water navigation the usual electric motors are utilised. The I | heavier oil engines are useful in those seas /! where the lighter fuel is unobtainable. ' ! ,;v When petrol is used, as in some types, •ov ' the radius of action on tho surface at the ■ 'fHr reduced speed of nine knots is 1450 miles, V . ' whilo submerged it is 45 miles at the iV -'i: ' . speed of 6.5 knots per hour. Special arrangements have been made ** to secure an adequate ventilation of the t . interiors of the boats. During surface , operations the air is drawn in from outside. When travelling submerged the •' heated atmosphere of the engine and the exhaled air of the crew is drawn off through ventilators, which pass it through various filtering, oxygenating and cooling devices, after which it is returned to the interior and is fit to be breathed again. V- Various safety appliances are fitted to prevent the y vessel being placed : hors de ' ' combat either by hostile fire or accident. The water ballast tanks can be emptied of water and charged with compressed air . very rapidly, there being a resfervoir of f r", / 1234 cubic feet capacity constantly mainL> tained under high pressure , for this pur- . ;'■ ■ pose. . . '