raft (n.1)
"floating platform," late 15c., originally "rafter" (c. 1300), from a Scandinavian source such as Old Norse raptr "log" (Old Norse -pt- pronounced as -ft-), related to Middle Low German rafter, rachter "rafter" (see rafter).
raft (n.2)
"large collection," 1830, variant of raff "heap, large amount," from Middle English raf (compare raffish, riffraff); form and sense associated with raft (n.1).
raft (v.)
1680s, from raft (n.1). Related: Rafted; rafting.