DCHP-1 Online
flat raft 
a simple boom (def. 3b) or raft in which one layer of floating logs is held by chained boomsticks (def. 2) and spaced cross-logs.
See also: flat boom
- 1965 A fourth raft, called "the Bag," consisted merely of a mass of logs collected without cross-logs as in the old type flat raft. It was used only in sheltered areas.
- 1965 A fourth raft, called "the Bag," consisted merely of a mass of logs collected without cross-logs as in the old type flat raft. It was used only in sheltered areas.