Thank you for the poly pipe raft "plan".

One question: "ขันน็อต" by putting studs (and nuts) through the pipe to fix the board to the pipes, would we not make holes in pipes and reduce their floating ability (buoyancy)? Furthermore, poly pipes are not strong enough to take the strains (twists and shears), one sudden movement of the raft under load may crack or break the pipes.

Perhaps tying the board to the pipes with "ropes" may help.