Problems with foam in my double skinned dory

[John the landlubber]

How can I tell if the foam is saturated without cutting up the floor? If it is saturated, can I dry it out with warm air or will that not work?

 

[otterbfishin]

Re: Problems with foam in my double skinned dory

Possibly drill a small hole, 1/8" or so and use a potted plant moisture detector. The hole could be easily sealed if the foam is dry. If it's wet you'll probably have to remove the floor and replace it. If so, use closed cell styrofoam boards, the blue or pink kind that is used in house building. I'm told that this kind of foam will not absorb moisture.<br />Good Luck!

 

[JB]

Re: Problems with foam in my double skinned dory

What make and model boat do you have, John?<br /><br />I have dried out a couple of Boston Whalers that had water in the between-hulls from outer hull damage. <br /><br />I drilled 1/2" holes at the bow and stern and blew warm air in one for about a day.

 

[John the landlubber]

Re: Problems with foam in my double skinned dory

Thanks guys. The boat is a rigid raider. It si 17"6X7"3. It was made by RTK marine some time between 1972 and now. Our special forces in the U.K use them as landing craft. I'm told nthey even drop them out of planes, lol. Anyway, I'm hoping to avoid re-foaming it as a lot of the boats strength and rigidity comes from the foam itself. From what I can gather, the foam is injected whilst the hull is in a jig at the factory so the hull doesn't go out of shape under the pressure of the foam expanding. These hulls are designed to carry a maximum load of 1 metric ton, and will take two 140hp outboards. Anyway, first I need to see where the water is coming from. The closest hull I have seen to mine is a dell quay dory (17ft).

 

[surlyjoe]

Re: Problems with foam in my double skinned dory

when fixing Boston Whalers we would open the hole for the repair and then dig out the wet foam, after letting everything dry, we'd pour some 2 part foam back in and let it expand out the hole. once cured, trim it to the shape minus the patch thickness or so and glass back over it. this is what the AMF rep told us to do.

 

[John the landlubber]

Re: Problems with foam in my double skinned dory

Problem is, I don't exactly know where the foam is wet and where it is good. Have not had the boat on the water yet and everything might be fine, but I know the previous owner had to dig out an d replace the foam in two positions. (When he got it it had two big holes where the foam was exposed.) The guy he got it off had cut out around his console and helm and left it outside for some time. This guy had also installed a bilge pump. This tells me I may well have some problems. I am stripping the old anti-foul off, gonna get the outside of the hull completely watertight, and then strip all the anti-slip off the deck. The deck has many small holes where it has been drilled for fittings in the past, and so do the gunnels. I am gonna dig

 

[John the landlubber]

Re: Problems with foam in my double skinned dory

out all the old sealant and redo them using a good quality one. Then using the drain plug and a forklift to lift the hull at all angles, I am gonna make sure there is no water left between the deck and the hull. At this point I would like to dry the foam out with warm air, then fill the deck with water and let her stand. then check the drain plug again. If there is no water between the deck and the hull after this journey I will be happy. Anyone ever achieve this or am I being unrealistic???

 

[blackwaterstout]

Re: Problems with foam in my double skinned dory

Can you seriously use that pink or blue building foam? That stuff would be much cheaper than the two part foam that sells for about $100 a quart.