RE: Float Size?
The above posts are great and also you may want to consider tethering your engine to something solid in the fuse (like the landing gear block) with a steel fishing leader. I was at a float fly and a guys wings folded and the fuse went in the drink pretty hard. The engine went to the bot of the lake. I have it on video and the guy gave the video to divers, but they still never found the engine.