Subject: Technique for avoiding collision with floating debris......
From: "Tom Dacon"

This hasn't been my experience. In calm inner waters, such as the inland
passage along the west coast of Canada, radar when set to short range can
commonly pick up a log or the top of a deadhead if it breaks the water's
surface, and it will routinely pick up a seagull standing on top of it. In
fact, I've even seen it pick up the riffles from a tidal rip.

Well, as long as you stay in "calm waters" it looks like you'll be OK. :-)

Capt. Bill