The Collaborative International Dictionary of English v.0.48:

Surge \Surge\, v. t. [imp. & p. p. Surged; p. pr. & vb. n.
   Surging.] [Cf. F. surgir to cast anchor, to land. Cf.
   Surge, n.] (Naut.)
   To let go or slacken suddenly, as a rope; as, to surge a
   hawser or messenger; also, to slacken the rope about (a
   capstan).
   [1913 Webster]