Pourable floatation foam for soft boat deck

[PensacolaJason]

I have a soft boat deck that I wanted to firm up a little. This is not a boat that I intend to keep for the long haul. It will be a bay boat that I use for a few years and then upgrade, so I didn't want to spend all kinds of time and money ripping up the floor and replacing stringers because the vessel is a bit older and it's just not worth it for me.

I was told about Pourable floatation foam as an alternative. My plan was to drill some holes into the floor and then mix and pour this flotation foam in small batches into the voids throughout the floor with the hopes that this stuff will provide some stiffness to the soft spots.

Does anyone have any experience with this stuff? Does this seem like a good way to go? Any tips or tricks for pouring and making sure it settles down in there nice and even.

 

[rockyrude]

Re: Pourable floatation foam for soft boat deck

Is the gamble that the supporting structure ( stringers,transom) will hold up until you get rid of it worth it? There is probably foam already in there and filled with water. You won't get any more in there anyways.

 

[PensacolaJason]

Re: Pourable floatation foam for soft boat deck

I cut a hole in the back of the deck and got in there with a flashlight to inspect under the floor and the stringers still looked pretty good from what I could see. And I didn't see any foam in there. I believe the sides are lined with foam on this boat.

It seems to be more an issue of the stringer placement which is causing the softness. There is one main stringer that runs down the middle of the boat and then two on each sides. It looks like the stringer placement was just too far apart to support only a half inch plywood floor.

 

[DAN M VAGOS]

Re: Pourable floatation foam for soft boat deck

You opened a can of worms because you will be told to fix it and spend tones of money on it and the guys on here are right and very helpful and want you to be safe but some times you dont have the money to spend or the time and just want to get a little ways out in the water. It all comes down to you if you feel safe and you want to risk it well its all on you it just takes common sense. As for the fome its very easy to work with and yes it makes the floor feel like a rock but I redid my floor so I dnt know what it will do to a rotted floor. That stuff has a lot of power when it expands.

 

[crabby captain john]

Re: Pourable floatation foam for soft boat deck

Not the way I'd go but.... I'd hate to want to repair/replace wiring, a transducer, fuel tank, fuel lines or anything else under there after encased in that stuff..

 

[metriccrescentwrench]

Re: Pourable floatation foam for soft boat deck

Simple answer, yes it'll firm up your deck.

Is it the right way to do a repair? Definitely not, but it'll more than likely keep you on the water for a little while longer. I'd definitely keep an eye on the transom for any signs of weakness and quit using the boat at the first sign of trouble there, most often a soft deck and transom issues come along at about the same time. AND, as has already been mentioned, make darned sure you're not going to be getting into fuel lines control cables, or wiring.

As far as installing it, I'd just start at one end/side.... pour..... move to the other side or opposite end.... pour.... Come back to the first side and pour some more until it's full and then move one. The thing you have to watch out for is that the stuff will keep expanding for quite a while and you don't want to end up with too much in one spot so you've got to allow plenty of time for it to fully react.

 

[crabby captain john]

Re: Pourable floatation foam for soft boat deck

Now it sounds like that may turn the boat to scrap if/when farther repairs are needed. I'd not want to try a repair after that by the sounds of things unless someone has done it and said it was of little extra work.

 

[PensacolaJason]

Re: Pourable floatation foam for soft boat deck

Luckily all cables, gas tank, everything is above the deck. under the floor is a very shallow void that contains nothing from what I can tell. It's only a basic 15.4 foot boat and the transom is very strong. I'm going to be cutting a few larger holes in the floor to inspect underneath before proceeding with any method.

 

[jigngrub]

Re: Pourable floatation foam for soft boat deck

I'm going to be cutting a few larger holes in the floor to inspect underneath before proceeding with any method.

Do that!

Your boat should have foam below deck installed from the factory, if it doesn't it's probably due to a PO removing it because it was wet and never replaced it.

Not having poured foam below your deck is a good reason for it to feel soft. Boat manufacturers only put in the bare minimum of framing for deck and hull support and rely mainly on the 2 part pourable expanding urethane foam to support the deck and hull. We see it all the time in the restoration forum.

If you decide to go with the poured foam, drill lots of holes with a hole saw. Drill the holes on 16" centers both ways for a solid pour with a minimum of voids. The holes will also act as pressure relief, expanding foam can be some strong stuff in an enclosed space:
The do's and don'ts of expanding foam - YouTube

 

[Boaterguy65]

EDIT: Boaterguy, you're breaking two rules at once, brother. If you've not read the forum rules, there's a link in my SIG below.

Let's let Jig have the last word on this one.