The Collaborative International Dictionary of English v.0.48:

Hance \Hance\ (h[a^]ns), Hanch \Hanch\ (h[a^]nch), n. [See
   Hanse.]
   1. (Arch.) See Hanse.
      [1913 Webster]

   2. (Naut.) A sudden fall or break, as the fall of the fife
      rail down to the gangway.
      [1913 Webster]