The Collaborative International Dictionary of English v.0.48:

Raftsman \Rafts"man\ (r[.a]fts"man), n.; pl. Raftsmen
   (r[.a]fts"men).
   A man engaged in rafting.
   [1913 Webster]

WordNet (r) 3.0 (2006):

raftsman
    n 1: someone who travels by raft [syn: raftsman, raftman,
         rafter]