Source : Webster's Revised Unabridged Dictionary (1913)

Catboat \Cat"boat`\, n. (Naut.)
   A small sailboat, with a single mast placed as far forward as
   possible, carring a sail extended by a gaff and long boom.
   See Illustration in Appendix.

Source : WordNet®

catboat
     n : a sailboat with a single mast set far forward