The Collaborative International Dictionary of English v.0.48:

Unbay \Un*bay"\, v. t. [1st pref. un- + bay to dam.]
   To free from the restraint of anything that surrounds or
   incloses; to let loose; to open. [Obs.]
   [1913 Webster]

         I ought . . . to unbay the current of my passion.
                                                  --Norris.
   [1913 Webster]