Soft Spot

[miguti]

Well, after reading repair articles until my eyes crossed I still have a couple of questions.
I recently bought an '89 21' Supra Bravura ski boat that looked great but had "a little soft spot behind the drivers seat. No problem I thought, cut it out, replace it and go skiing. Those of you with older boats know where this going, I have now removed all the floorboards (deck) both sides (with my fingernails). The two floor stringers on each side, which are about 1 x 6, fiberglassed, are also damaged. The area between the hull and the floor is full of foam.

Ques #1: Is the foam a mandatory item, legal or structual or otherwise? It seem to me that the underside of the floor (deck) can never dry out with that stuff in there. If it has to be there, what is the favored type?

#2: I think I'll just "core out" the deck stringers and glass in a fir 1 x 4 at the top of the remaining fiberglass that went up each side of the rotten 1 x 6. Then lay a piece of glass over the top and down the sides a couple of inches to seal it. Does this seem practicle over completely removing the stringer, glass and all and replacing everything? If I use epoxy resin will there be problems rebonding the old glass to the new stringer?

#3: I bought some 1/2" Marine Plywood to replace the floor. I was thinking of coating the bottom and edges with a couple of coats of epoxy resin to seal it. Then, rather than nailing or screwing (leaks) I was going to thoroughly coat the top of the stringers with epoxy before installing the floor. Then finish the top with glass and resin as originally done. Problems or suggestions?

#4: I agree with those of you who believe that carpet is the beginning of the problem but it does look good so I'm going to hope that the plywood sealing and a conscientious "drying after use" program will be enough. Since the rubber on the bottom of the carpet looks a little thin to be counted on, has anybody had any success with extra carpet glue to help seal out the water from the top of the deck? What kind?

I am hoping to tap into some of your experience (good and bad) and maybe get through this.

Thanks, Rich Fowler

 

[salty87]

Re: Soft Spot

welcome to the wonderful world of boat rebuilding

i have an 87 supra saltare, i'm very familiar with how your boat was built. the supra website has a decent collection of pics of several older supra rebuilds (supraboats.com/bbs/forumdisplay.php?f=6)

on to your questions
1. foam is only required by a manufacturer, so...not required for you
2. that's alot of work to get a patch job. why not just do it right? why use epoxy?...esp with patched stringers?
3. not sure, i used poly resin. i used sealant on screws. all glassed over.
4. carpet is the only thing i was going to put back in. my old floor rotted out from below...wet foam. not from the top down, from wet carpet. let your boat dry before you cover it.

the problem with foam is that when it is poured into a hull, it seals everything up. the foam then starts to collect and absorb water.

water is the enemy, not foam or even carpet. search lining the hull with plastic to pour foam, it allows you to use foam and still get drainage.

 

[oops!]

Re: Soft Spot

do more reading on the subject of rotten decks....foam....and stringer replacement....

especially in the way of the 1x4......plywood on edge is far stronger than dimensional lumber......

as far as the deck......a good option now used bu the mfgr's is to gellcoat the deck....and add a snap in carpet......done for life !

chreers
oops

 

[zach103]

Re: Soft Spot

take at look at oops extension project it has a lot of good info with pictures to help you.

 

[oops!]

Re: Soft Spot

by the way.....welcome to i boats......

this this is the place for all the boat building facts you will ever need.....

the guys here are top notch.....and can walk you right thru any thing you will ever need.

read the compleated projects forum......it is a really good source of info

cheers
oops

 

[miguti]

Re: Soft Spot

Salty, Opps and Zach
Thanks for the good information, I can work on airplanes but know nothing about boat structure repair.
Besides the obvious problem of sinking, do you see any problem with leaving out the foam? It really seems like the boat could dry out a lot better without it. Has anybody come up with a good way remove the stuff?
I was going to use epoxy resin because I thought I read that it gave a more dependable bond. Do you think that polyester resin would be a better choice to seal the marine ply?
My choice to resin in a new 1 x 4 stringer was made because cutting and fitting all new stringers seemed a little daunting for someone with my lack of experience and I thought that if I got a good bond to the existing fiberglass, it should be as strong. However, I think Opps makes a good point about cutting plywood stringers.
If anybody else has any thoughts or experience to relate, I can use all the input I can get.

Thanks, Rich

 

[salty87]

Re: Soft Spot

none of this is very technical work. if you can read a manual, you can do this.

shaping stringers is nothing more than either time or ingenuity. or both if you out-smart yourself.

foam isn't necessary. i'm only on small inland lakes, i doubt you're going offshore either. if it can drain, it can't cause rot though. you'll notice once you get rid of all the foam that there are a few areas that gathered water...low spots in the hull. let these drain to the bilge and you've got it beat.

i used a sawzall to cut the foam, then a pry-bar to pop chunks of foam out. nasty stuff.