You could also use garden hose as a mold to make the ribs, etc., but you'd want to remove the hose to save weight, so mold release would be needed.

> The ribs, as originally built were contructed of half tubes of
> some fiberous material (picture a paper towel roll cut in half lengthwise).
> they were about one inch in diameter. These tubes were laid down on
> the interior of the hull, diameter down. They were then glassed over
> with strips of non woven fiberlass matting, around 8 inches wide.
> These ribs were placed longitudinally for a keel, and abeam in 4 places
> for rigidity.

> The matting/hull interface gave way eventually and the whole
> structure weakened. I ripped out what I could and plan to replace
> the ribs, and add a couple more, where I cut hatches. I could probably
> fashion cardboard tubes and laminate over them, but that seemed like
> too much work, so I plan on cutting some 1/2" x 1" by whatever
> strips of pink foam, chamfering the edges with a utility knife and
> sticking them down (they will conform to the hull nicely) in place,
> then covering them with 8 inch strips of cloth. I am pretty sure this
> will be both strong and light.