Soft Spots

I have a 81' Hobie 16 that I love like a child but last time I was out we capsized and while trying to right the boat noticed quite a large soft spot in my port hull between the two pylons on the inner side. I was thinking that I could maybe beef up the fiberglass there for the remainder of the season until winter when I can look at other options. I was thinking about taking some fiberglass matting and resin and applying multiple layers to the soft spots. I was wondering if anybody has ever thought about this and if yall think it would reinforce it much? Let me know what you think, I'm on the verge of doing about anything to save my baby, thanks

the epoxy injection is nice and easy.

So should I drill holes about 5cm apart at the very top of the soft spots and continue to fill the holes full of epoxy until they fill up and overflow?

sounds right.

Make sure you dig out the foam in there with a hangar first. Be careful not to puncture the second layer.

There is an article at www.hobiecat.com on how to do it. Tech tips or something like that. Saw it yesterday.

Don't let it go too long. The first heavy air day can fold the hull in half. Seen it happen a few times.
cheers
Bill

Ben it depends what is wrong with your boat to determine the technique but if you go with the epoxy makes sure they are 10-5cm apart. I have done this many of times but its not the best for the boat.

Jules

I drilled 96 holes in the side of the hull all on a grid about 5cm apart and removed all the broken up foam from the inside with a coat hanger and an industrial vacuum. The epoxy is in the mail right now and as soon as it comes i'm gonna start filling it up. If this is not the best thing for the boat what is?

Removing the foam and replacing with solid resin is not the best idea. This will then be a 1/4" thick sheet of epoxy in the hull wall? Heavy and will heat and possibly distort the hull wall when curing. If the epoxy is too stiff it may also crack.

If you have already removed the foam, you should probably cut the outer glass layer off and fill the inner area with glass mat or more of the foam sheeting that was originally in there and laminate it back together.

Best to leave the foam in and inject the resin to re-laminate the delaminated layer together. Typically the foam is fine and is just not bonded to one of the glass layers. I have personally done this to a 16 deck back in 1984 and that boat was just fine last I heard. The resin I used was somewhat flexible and not brittle. Something from a company called Boat Life. The stuff was called Git Rot. A two-part epoxy that is really easy to mix and inject from the plastic bottle it comes in.

Here is the tech image from the Hobie Cat Support pages. Pretty rough but explains it pretty well.




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ok, so now that the foam is gone where can i get more foam to inject in there? Would a carpet type foam from lowe's or something do the trick or do i need something else. if i go with fiberglass matting we are talking about a whole lot of it b/c the spot is about 3 feet long, plus would have to fill in a quarter inch hole. should i maybe look for some type of plumbing foam or something that would fill in the area w/o me having to cut the top layer of glass off?

The foam is a special type for laminating with fiberglas. It comes in big flat sheets. I would guess that a foam used in surf boards would work, but the hardware type is likely a no go. not dense enough and not closed cell. Any boat yards in your area?

Not without a four hour drive down to wilmington. I had read on here where a guy used some stuff called great stuff foam to fill in the area and apparently it ended up ok. what's your take on that?

I have no experience with foam injection for this issue. Biggest concern of mine will be the closed cell (water tight) aspect of the foam and the expansion. The expanding foam will likely force the two glass layers apart somewhat. You may have to have something solid agains the outer skin so it doesn't create a big bump area.

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I did some research on this great stuff foam and here is the website, http://www.dow.com/greatstuff . It says it bonds to fiberglass and creates an airtight closed cell suface impervious to most solvents. The expansion rate for this stuff is minimal and at most 3 fold. I figure if i do it slowly in layers i might be ok.

Used the "great stuff" today....looks like it worked perfect. Expanded at not too large a rate and filled in everywhere. I am very pleased.

When I tried to inject epoxy for my softspot, it wouldn't inject until I cleared the foam out of the way. Even then, I had to cut away the whole deck and reconstruct it, using hardwood to reinforce the area.

Its rock solid now.

I used this great stuff to replace the foam and then fiberglassed over the area and it's rock solid. I'm very pleased. Guess the real test will come in the first day of heavy air.

See what happens when you ont listen to the person who makes the boats.

See what happens when you dont listen to the person who makes the boats.

well for an 81 that's starting to show age it's not worth a four hour drive down to wilmington to get what the "guy who makes the boats says" i'm gonna part w/ her and get a new one. Thanks