submarine mine
Webster's Dictionary (GCIDE)
Submarine \Sub`ma*rine"\, a. Being, acting, or growing, under water in the sea; as, submarine navigators; submarine plants. [1913 Webster]
Submarine armor, a waterproof dress of strong material, having a helmet into which air for breathing is pumped through a tube leading from above the surface to enable a diver to remain under water.
Submarine cable. See Telegraph cable, under Telegraph.
Submarine mine. See Torpedo, 2 (a) . [1913 Webster]