The Collaborative International Dictionary of English v.0.48:

Gunnel \Gun"nel\, n. [See Gunwale.]
   1. A gunwale.
      [1913 Webster]

   2. (Zool.) A small, eel-shaped, marine fish of the genus
      Mur[ae]noides; esp., M. gunnellus of Europe and
      America; -- called also gunnel fish, butterfish, rock
      eel.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gunwale \Gun"wale\, n. [Gun + wale. So named because the upper
   guns were pointed from it.] (Naut.)
   The upper edge of a vessel's or boat's side; the uppermost
   wale of a ship (not including the bulwarks); or that piece of
   timber which reaches on either side from the quarter-deck to
   the forecastle, being the uppermost bend, which finishes the
   upper works of the hull. [Written also gunnel.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

gunnel
    n 1: wale at the top of the side of boat; topmost planking of a
         wooden vessel [syn: gunwale, gunnel, gun rest]
    2: small eellike fishes common in shallow waters of the northern
       Atlantic [syn: gunnel, bracketed blenny]