The Submarine Torpedo Boat
Its Characteristics And Modern Development

24 THE SUBMARINE TORPEDO BOAT capable of resisting hydrostatic pressure due to a depth of 165 feet. The watertight hull is formed of nine circular welded sections, the amidship three of which are cylindrical and the others fore and aft are slightly conical. Each section is divided by bulkheads into a watertight compartment. The bow section contains two torpedo tubes and acces- sories and can carry altogether three torpedoes; the next section is occupied by the crew and storeroom for bat- teries, and contains also a galley and lavatory accommoda- tions. The amidship sections contain the inner ballast tanks and steering and all other navigating and operating gear. The engine room contains internal combustion engines of the Diesel type and electric motors, and the last watertight section is reserved for another battery of elec- tric accumulators. Between the deck platform and the inner hull all the kerosene fuel tanks are fitted. The propelling power for surface navigation is derived from two two-cycle heavy-oil engines aggregating 600 B.H.P. driving two reversible screws. Two electric motors developing 320 H.P. are used for propulsion when the boat is submerged. The engine room auxiliaries comprise two main and one auxiliary motor driven bilge pumps, two hand pumps, air compressors and other accessories. Par- ticular attention has been given to equipping with various means of salvage and safety appliances and air purifying devices. The surface speed is 12 knots and the submerged speed is 8.6 knots. At an economic speed of 10 knots, the radius of action on the surface is 1200 miles and at 6 knots submerged the radius is claimed to be 60 miles. Looking back we can see that up to the time of Holland, what development there had been was of a very erratic