Chapter 2 — SUBMARINES AND ANTISUBMARINE UNITS 



PROPULSION 



Conventional submarines use diesel engines 

 for propulsion when surfaced, and batteries when 

 submerged. Nuclear-powered submarines get 

 their propulsion from atomic reactors. 



Conventional Submarines 



When on the surface, a submarine's twin 

 screws are turned by electric propulsion motors 

 powered by generators driven by diesel engines. 

 Upon submerging on snorkel, virtually the same 

 performance can be had, but depth of submergence 

 is limited to the length of the snorkel mast. 

 Submerged to greater depths, the submarine relies 

 on large banks of storage batteries to drive its 

 electric propulsion motors because combustion 

 engines require far more air than is available. 

 Here, endurance is limited strictly to the con- 

 dition of the batteries. Theoretically, if batteries 

 are well charged, a speed of 1 knot can be main- 

 tained for about 50 or 60 hours. At full speed, 

 however, the batteries are exhausted after ap- 

 proximately 1 hour. 



One way of forcing a battery-powered sub- 

 marine to the surface is to outwait its staying 

 power. The submarine eventually must use its 

 snorkel, or surface, to recharge batteries and 

 replace air. 



Nuclear Submarines 



Atomic power has brought close to reality the 

 dream of having a true submarine, that is, one of 

 unlimited submerged endurance and range. The 

 Nautilus refueled for the first time over 1 year 

 after she commenced operating. The Triton 

 circumnavigated the world completely submerged. 

 The Nautilus and Skate pioneered exploration of 

 the north polar seas beneath the icecap, all made 

 possible only by nuclear energy. The human factor, 

 and the quantity of supplies that can be carried, 

 are the main limitations to the endurance of 

 modern submarines. 



SUBMARINE ARMAMENT 



Armament of a submarine depends on its 

 design and mission. The attack-type submarines 

 normally carry only torpedoes, but they may be 

 employed as minelayers. Fleet ballistic missile 

 submarines carry 16 Polaris missiles, and they 

 have 4 torpedo tubes forward. 



Torpedoes 



The torpedo is a self-propelled underwater 

 weapon having either a high-explosive or a 

 nuclear warhead. Conventional warheads are 

 loaded with up to 1000 pounds of HBX explosive. 



Underwater explosion of the torpedo warhead 

 increases its destructive effect. When a pro- 

 jectile explodes, a part of its force is absorbed 

 by the surrounding air. Upon explosion of the 

 torpedo warhead, the water transfers almost the 

 full force of the explosion to the hull of the 

 target ship. 



Fleet-type and Guppy submarines are fitted 

 with 10 tubes, 6 in the bow and 4 in the stern. 

 Spare torpedoes are carried in ready racks near 

 the tubes. On war patrol, a submarine of this 

 type usually puts to sea with a load of 28 torpe- 

 does aboard. 



Torpedoes are propelled by gas turbines or 

 electric motors. Turbine types have maximum 

 speeds of 30 to 45 knots, with a maximum ef- 

 fective range of as much as 7 1/2 miles. Elec- 

 tric torpedoes usually have less speed and range 

 than turbine types, but from the submariner's 

 point of view, they have the advantage of leaving 

 no visible wake. 



Torpedoes are of the straight-running, acous- 

 tic homing, or wire-guided types. The straight- 

 running torpedo has automatic control devices 

 that hold it on a preset course at a preset depth, 

 whereas the acoustic homing type can steer it- 

 self toward its target. It may be either active 

 or passive. The active acoustic torpedo sends 

 out pulses of sound and homes on the echoes that 

 return from the target. Passive types home on 

 the noises emanated by the target. The wire- 

 guided type of torpedo is directed to the target 

 by signals sent through the wire from the launch- 

 ing submarine. 



Two new submarine weapons are Astor and 

 SUBROC. Astor is an electric-propelled Mk 45 

 torpedo with a nuclear warhead. It is wlre- 

 gulded to the target, and has a range of over 

 10 miles. The SUBROC is an antisubmarine 

 rocket with either a conventional or a nuclear 

 warhead, and has a range of over 20 miles. 



After it is launched from the submerged 

 submarine, SUBROC's solid-fuel motor ignites, 

 and the rocket enters the air. At some point 

 in its trajectory the rocket motor separates 

 from the missile. The missile, which is di- 

 rected to its target by an inertlal guidance 

 system, m.ikes a supersonic reentry into the 

 water, sinks to a predetermined depth, and 

 explodes. 



13 



