Task: Question Understanding
Input (English): Context : Stockpiles of Mark 10 Mod 3 torpedoes were used extensively during the first part of World War II due to short supply of the newer and longer (246 in (6.2 m) Mark 14s, with some fleet submarines carrying a mixture of both types on patrol. Mark 10 torpedoes, and those developed at the same time (Mark 9 air- and Mark 8 surface ship-launched) used essentially the same control package (the Ulan gear) as the newer Mark 14 for depth and direction. The running depth could be set to between 5 and 35 m (16 and 115 ft). The gyro angle could be set for a new course up to 90 degrees port or starboard from the current course of the submarine before launch. The Mark 10 would run out of the tube straight ahead for the ``reach'', then turn to a new, pre-set course, through a total angular targeting of 180 degrees over the end of the submarine, and then run on this intercept course straight to the target. To use a Mark 10 Mod 3 (the earlier Mark 10 torpedo mod numbers would not work)) of torpedo in fleet submarine tubes required a gyro angle setting spindle adapter be slipped into the torpedo housing to extend the reach of the spindle into the torpedo. 
Question : What year was Mark 10 torpedo introduced?
Output (English): service entry