cat·a·ma·ran 
(kăt′ə-mə-răn)
(kăt′ə-mə-răn)n.
1. A boat with two parallel hulls or floats, especially a light sailboat with a mast mounted on a transverse frame joining the hulls.
2. A raft of logs or floats lashed together and propelled by paddles or sails.
[Tamil kaṭṭumaram : kaṭṭu, to tie + maram, wood, log.]
catamaran