expanded foam in hull question

Yes, which I thought about doing but if the boat sinks, it's going all the way to the bottom. It also takes the coast guard rating away too. I wanted to use the space under my floor for a ski locker but after adding ribbing back in there wouldn't be enough room anyways. So I figured the best thing and least time and money consuming thing to do was just refoam it.

All this talk about foam or not to foam. Either way, I think the boat will survive. Basically, i agree that the foam is not a structural element other than supporting the original fiberglass floor. But if you plywood, that is a moot point. So, to foam or not to foam boils down to a few questions:
1. Do you want the floation?
2. Do you want the sound deadening qaulities?

Yes, the bottom of the hull will flex a bit, but the fiberglass laminate can handle it, so no worries there. And to all those that are worried about water logged foam again...modern foam does NOT SOAK UP WATER!

Now, let's open up another can of worms. The wood stringers are not really structural either and the boat will stay together with out them....but, the engine might end up against the transom. Evidence of this is that when is the last time you heard of boat breaking in half or coming apart due to rotten stringers?

And...if you remove the gelcoat from the fiberglass laminate, you can shine a light through it no problem. So, if you scratch off the gelcoat on the keel and then can see daylight, not necessarily a big deal.

Yes, I would foam due to the reasons stated early on in this thread. I agree, the foam will dam the water, but only small amounts of water at the boundary layer. If the stringers are well glassed, this would not be much of an issue. Also, I find it hard to believe that one could make the under floor area totally water tight over the long run. I also understand you point about an airtight space, but I doubt the USCG allows such a concept.

Now, lets look at it another way, if you do not foam, water can get in, stay in and theoretically fill up the cavity. Slooshing around at will. Not a pretty thought. If there is foam in the cavity, only a minor amount of water can get in. Just a spure of the moment thought.

Now, for a lake boat, if no foam and it sinks. No big deal, just swim to shore.

Now, for a lake boat, if no foam and it sinks. No big deal, just swim to shore.[/QUOTE]

I don't know about you but it's a big deal to me if my boat is sitting on bottom of the lake in 60' of water. I could recover it if it was floating on the surface but not on the bottom. Maybe that's just me since I don't have insurance on mine.

80 Ski-Tique wrote: So I figured the best thing and least time and money consuming thing to do was just refoam it.

THE least time and money is to throw a double-armfull of pool noodles under the new floor. They wont trap water, let air circuilate and would make a flooded boat level and recoverable, it doesn't have to float like a Bwhaler cut in half.

I can't speak for all aluminum john boats but ours had foam under the bench seats. I know what your saying but I am capable of rewiring and rebuilding motor and trans. if needed be. I could always send the trans. to you if that was the case I had insurance on it when I bought it but the insurance premiums after two or three years were more than I paid for the boat when I bought it. It's a risk I decided to take, and I am very experienced on the water and very unlikely to hurt someone from carelessness. If my skier gets hit with anything it most likely going to be the idiots on jet ski's and I do the best I can to avoid that.

what if you hit a submerged rock and the sue happy passenger goes through the window? it happens....i have to put the phrase in, I myself have been boating for 20 some years and went into a dead stop from 52mph last year on a sand bar, the bodies kept going, no major injuries..couple of bumps and bruises, couldve been worse lol

Well it is the difference of me going to the lake or not. For whatever reason my insurance on my one boat is close to 2K a year. I totally understand what you guys are saying but first of all I don't bring sue happy people on my boat and second we have never had an accident on the water, and yes I know that doesn't mean I won't but like I said it unfortunately is the difference of me using my boat or staying at home and looking at it. In over 60 years of my immediate family's boating we have fortunately never had any accident to speak of. Mainly because we were taught all the navigational rules and laws and codes of conduct before we were allowed to drive. If everyone was brought up this way we wouldn't have any accidents to speak of.

if someone can sue, they will no matter who it is.

Ditto on the insurance.

Most 'other' skiboats only have a few strips of 2x4 looking strips of foam strapped to the hull with fglass and also under the gunnel, and they meet level-flotation rules.

I believe full-foam under the floor is a massive amout of flotation, and that entire volume is not critical to make the boat recoverable, nor level.

eric lavine wrote: what if you hit a submerged rock

What happens if you hit a floating rock?

$2k for boat insurance??? WOW! We're right in line with the $2-300 per year.

I must be lucky, our boat insurance only added $100 to the yearly cost.