cuddy n : the galley or pantry of a small ship
A Cuddy is a small cabin in a boat. A Cuddy boat is a boat with a small cabin with maybe a small galley and small head. It may have a small berth also. Normally the Cuddy is not tall enough to stand in. "Cuddy Cabin", while a redundant term (Cuddy itself means cabin), is a common term among small boaters.
A Cuddy boat is popular with people who want a little shelter and storage space but do not want to upgrade to a full cabin boat.