SUBMARINE WARFARE.

Hokitika Guardian, 30 May 1917, Page 4

SUBMARINE WARFARE.

Offensive and Defensive Powers. In answer to questions by a correspondent as to tbe method used by submarines in firing torpedoes, the “Army and Navy Journal ’’ says: “ A submarine fires her torpedo when submerged. She fights warships only when submerged, but fights unarmed ships on tbe surface with her gun, which has been of three and four inch calibre, and will probably be increased to six inch. Submarines, when about to fire a torpedo, usually submerge to about fifteen feet. The torpedo is always ejected into the sea from a submerged tube and the torpedo maintains a straight oourse at the desired depth nntil it hits its object. If tbe torpedo should be fired from a submerged l übr, «f-»y at a greater depth than fifteen feot, and the la’ter was the depth decided for it, the torpedo rises to the desired level. A hydrostatic and pendulum gear forces the torpedo to travel at the desired level and at the set depth. A gyroscope makes the torpodG travel in a straight line in any given direction. “ Torpedoes, are usually discharged at about 2000 yards, or just over the mile, and at a lesser distance if found expedient. The Whitehead torpedo maintains a speed of thirty-eight knots at 2000 yards, and a speed of forty-two knots at 1000 yr-rds. The wake of the submarine periscope on a smooth sea can be picked up at 5000yds, and submarines cannot ba discovered at more than about five miles. . They have been known-to approach a battleship within 500 yards in a choppy sea before being discovered.

“ 8 The most effective guns used against submarines are foar-iGcb and six-inch and six-pound rapid firers. The four-inch gun fires a shot weighing thirty-three pounds, and it can be fired very rapidly. It would be possible to fire fifteen shots a minuteTbe four-inoh gun has been fired so rapidly that five shots have bsen sailing through the air in a procession at the same time. A six-inch gun, with a good crew, cun fire about six aimed shots a minute. Another effective arm against submarines is the six-pound rapid fire gun, which has been fired at the rate of twenty-two aimed shots per minute. These shots would go into the hull of 'a submarine at a distance of 8000 yards as easily as through pasteboard, The six-pounder is considered one of the best defensive guns there is against submarines.

“The lowest depth to which a United States submarine is known to have submerged is 285 feet, but this is an unusual depth, and from 150 to 210 feet is ths general requirement in snbmergiDg tests. The ordinary depth which a submarine needs to submerge completely is about sixty-feat. Some of the latest type 3 of submarines built for the United States are of 1200 toDS displacement, a-d are 250 feet long. They have a radius of action of 8000 miles and surface speed of twenty knots and submerged speed of thirteen knots.”