[2] The Mark 5 was a "hot-running" (powered by heated air) torpedo, as opposed to previous Whitehead designs, which were "cold-running".
Around 500 units were produced by the Naval Torpedo Station and Vickers Limited.
This variable speed was set before loading the torpedo in its tube by adjusting the reducing valve.
[2] The Mark 5 was, however, overshadowed by the increasing efficiency and range of Bliss-Leavitt torpedoes.
[2] The Mark 5 was launched from destroyers, torpedo boats and other small ships.