Solid Tube RIB

[osirissail]

I have seen many folks try/do the expandable foam inside the tubes of a "Swiss cheese" leaking dinghy. Generally speaking it does work but you have to cut a few more holes through the tube to get foam into the area far from the normal valve/filler location. Also the tubes end up with a considerably wrinkly rough "knobby" surface as the foam does not expand uniformly in all area.
- - What others have done is to cover the tubes with layers of fiberglass cloth and resin converting the inflatable into a "hard" dinghy. This technique usually ends with a much smoother tube surface than the expandable foam.

[beau]

The problem would be that ALL foam will eventually take up water unless sealed, and then the boat will be heavy.

[barnakiel]

There are some rotomolded boats like this.

I have seen people laminating old and leaky dinghies this way and getting a similar result if a bit less visually pleasing.

b.

[osirissail]

Originally Posted by beau

The problem would be that ALL foam will eventually take up water unless sealed, and then the boat will be heavy.

Very true and to add bad to badder - the expandable foam in the quantities needed is quite heavy in and of itself. It is possible that doing the foam or fiberglass outside covering you will be significantly changing the empty weight of the dinghy.

- - Normally as the dinghy ages, the hypalon or PVC is attacked by UV and starts leaking just about everywhere. And also the cloth gets easier to puncture and tear with age.
- - I found after years of attempting to patch leaks and failures - the "secret". I had to translate it from the instructions with a box of 2-part hypalon glue from Italian to English. The "secret" translated in English was "extreme pressure for 2 days." That means that after cleaning and applying the 2-part glue and patch you need to take two wooden boards/planks and some "C" clamps and squeeze/compress the patch to the tube with the C-Clamps and boards and then let them cure for two days. It can be quite challenging to do this with leaks near seams or attachments and is probably why professional dinghy repair shops charge so much money.

[Captain Bill]

Try looking up Rigid Bouyancy Boats (RBB) instead of Rigid Inflatable Boat (RIB) and you'll get what you're looking for.