On 12 Sep 2005 14:03:34 -0700, wrote:

If it's for a kayak or canoe you may look up sponsons.
Sponsons have become a nasty word in the kayak news groups because
there were some safety accusations made concerning their lack of use.
That or you could make something up with PVC pipe and end caps.
( The latter is great for Hiding guns in. (Water tight and tough should
you want to burry them : )).

I'm looking for something more about this size:

http://www.islander-pontoon-boats.com/hydro-bike.html

Maybe PVC would work...