The Collaborative International Dictionary of English v.0.48:

Sea cock \Sea" cock`\
   1. In a steamship, a cock or valve close to the vessel's
      side, for closing a pipe which communicates with the sea.
      [1913 Webster]

   2. (Zool.)
      (a) The black-bellied plover.
      (b) A gurnard, as the European red gurnard (Trigla
          pini).
          [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "sea cock":
   ball cock, ball valve, bung, bunghole, check valve, cock, cork,
   drain cock, draw cock, faucet, gate, lid, needle valve, peg,
   petcock, pin, plug, spigot, spike, spile, spill, stop, stopcock,
   stopgap, stopper, stopple, tap, valve, valvula, valvule