The Submarine Torpedo Boat
Its Characteristics And Modern Development

32 THE SUBMARINE TORPEDO BOAT great speed the destroyer could cover the intervening distance in from six to eight minutes or at least could approach near enough to make an effective attack by gun- fire upon the submarine with disastrous results to it, unless it had first been able to effect cover under water. The complete change from light to submerged condition should therefore be effected in from two to tliree minutes. The effectiveness of a submarine attack depends for the most part upon its ability to load and fire several tor- pedoes in quick succession, for it takes considerable man- euvering greatly handicapped by lack of speed to get into position for firing. This is occasioned by the fixed posi- tion of the torpedo tubes as an integral part of the hull, and means that the axis of the submarine must be brought to train upon the target. Having once attained this posi- tion, a target and especially one of high speed will remain in the zone of fire for only a very short period of time. The submarine must therefore be equipped with armament efficiently designed and capable of quick operation in order to take the greatest possible advantage of these few seconds. The real necessity of this may be better understood by the uninitiated after taking into consideration the great disadvantages under which the submarine is working, and the really small chance that is afforded her of making a successful hit. The periscope, the eye of the submarine when under water, affords a very poor means of judging the distance or range of the object to be attacked, and although the eye-piece of the periscope is graduated with cross-hairs to better enable this calculation to be made, the base line for which these graduations are provided must remain more or less indeterminate and consequently the