Stringers,foam,pourable no brains ect...
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=5364
Printed Date: January-17-2025 at 8:43am
Topic: Stringers,foam,pourable no brains ect...
Posted By: Waterdog
Subject: Stringers,foam,pourable no brains ect...
Date Posted: December-14-2006 at 7:33pm
The problem rotten wood.
The fix - get rid of it -
I'm thinking about a composite stringer that could be fitted in the original fibergla$$ shell that housed the stringer. Like the pourable stuff ,grind off the top,hog out all the wood & now we have a mold.
The pourable stuff is heavy and not as strong as we would like to think.
The foam is light and fairly stiff, but the new boats are a different design so it really doesn't apply.
Now the club sandwitch -
A composite 2x8(ish)could be layed-up in a mold or in the bottom of the boat .
2 layers of heavy gla$$, 3/4 thick "general plastic's" closed cell foam sheet, 2 layers heavy gla$$, 2 layers of roving in the center, 2 gla$$ ,foam,& 2 gla$$ on the other side.
The foam is tough it stands up to 100 psi & 350* F auto-clave cure cycles on military aircraft parts. The 4x8 sheets can be had in any thickness.
A molded stringer could be just under size width wise, buttered with adhesive and slipped into the original fibergla$$ form.
In the boat it could be built up in the fibergla$$ shell on each side with pourable foam in the center.
Anyway it's a start - fire away
- waterdog -
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Replies:
Posted By: SkiBum
Date Posted: December-14-2006 at 9:46pm
I have been planning to remove the rotten floor and foam in my boat all summer. I have planned to replace the stringers as well. I toyed with the idea of using the SEACAST system. Too heavy. I thought about making the stringer four times wider on the bottom and twice as wide on top constructed of 8lb or 16lb foam wrapped in high strength glas. Too risky.
I figured it out. I am going to remove the wet floor. Then I am going to remove the wet foam. Then, one at a time, I am going to cut out the rotting stringers.
I am going to use non-treated wood, glas everything, replace the foam with 4lb closed cell.
End State: The boat will be several hundred pounds lighter, watertight, and will hold for another 20 years.
Then, maybe I'll make a full pa$$ at 35 off!
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Bill
http://www.freewebs.com/billsboatworks - http://www.freewebs.com/billsboatworks
www.freewebs.com/billsboatworks 1987 SN Rebuild Project
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Posted By: 8122pbrainard
Date Posted: December-15-2006 at 5:49am
Skibum, Use epoxy resin to replace the floor. It doesn't absorb water like polyester resin does. Pete
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/diaries/details.asp?ID=1622" rel="nofollow -
54 Atom
/diaries/details.asp?ID=2179" rel="nofollow - 77 Tique
64 X55 Dunphy
Keep it original, Pete
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Posted By: SkiBum
Date Posted: December-15-2006 at 7:52am
Roger that, thank you.
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Bill
http://www.freewebs.com/billsboatworks - http://www.freewebs.com/billsboatworks
www.freewebs.com/billsboatworks 1987 SN Rebuild Project
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Posted By: GottaSki
Date Posted: December-15-2006 at 8:50am
Consider pool noodles instead of foam. Airflow is better to prevent rot and they are lighter, and it will never soak up again.
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole
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Posted By: hasbeenskier
Date Posted: December-15-2006 at 7:43pm
Waterdog:
When I started the pourable stringer post I was trying to create a short cut to the path I took with the 81SN I am restoring. See post "81 top to bottom." During the responses and input on the pourable post I did not know of your background with composites. I agree with the approach listed above and have considered it myself. I suspect that the time savings would not be significantly greater than if the stringers and their wraps were cut away and replaced as done in the 81. I have two more boats to redo and I want to see how the pourable polyester works. I am concerned about the weight factor more than any thing. It is my belief that the strength and construction of the stringer wraps are much more important than their core. Any thoughts?
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hasbeenskier
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Posted By: hasbeenskier
Date Posted: December-15-2006 at 8:09pm
Is'nt this fun?
Epoxy it is more expensive than polyester. Additionally, epoxy will stick to poylester but polyester will not adhere to epoxy. To me it is like getting chocolate in my peanut butter.
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hasbeenskier
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Posted By: The Lake
Date Posted: December-15-2006 at 8:30pm
Hey BJ,
I'm just waiting for you to figure out the best way--I know my day is coming on redoing the stringers. So far the boat runs; it stays in one piece, myself and my family can ski--so life is good, and will be even better when spring comes, and please no Florida comments.
Chuck
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Walk on Water
www.coldwater.me
http://correctcraftfan.com/diaries/details.asp?ID=775&sort=&pagenum=3&yrstart=1966&yrend=1970 - 69 Ski Nautique
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Posted By: Waterdog
Date Posted: December-16-2006 at 1:48pm
Hasbeenskier-
Location is a big plus for leaving the gla$$ stringer shells in place. Building the laminant on the inside will make a clean factory look.It will be much stronger than the wood stringer & won't rot. I'm tempted to build a mold & fab up a couple stringers that could be bedded in place with foaming epoxy adhesive. There seems to be a need to repair our antique-fiberglss boats with modern technology. I'd like to have a phone con if we could. I slept thuogh my high school typing cla$$ ! Typin - i dont need no stikin typen!!!
w/d
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Posted By: hasbeenskier
Date Posted: December-19-2006 at 3:51am
H20dog
Sorry for the delay in my response. Call me any time C# 727-612-4772.
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hasbeenskier
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Posted By: David F
Date Posted: December-19-2006 at 9:24am
My thoughts:
The wood stringers are not necessary in the boat for structural reasons. The purpose is to maintain the shape of the hull and prvent oil canning. But, the main purpose of the wood in the main stringer is to provide a firm mounting point for the engine and transmission. With that said, the fibergla$$ shell around the wood stringers should do the job (this is why you never see a broken in half boat that has rotten stringers). But, you need to come up with a suitable mounting system for the drive train. These are just my thoughts, do not bet your life on them.
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Posted By: Waterdog
Date Posted: December-19-2006 at 10:55am
David F
I really dislike lag bolts in boats, anywhere there installed is a problem waiting to happen. The only way to connect the engine & trans mounts to the composite stringer is with an encapsulated bracket. The resin lag bolt interface will fail, not if ,when.
waterdog
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Posted By: jbear
Date Posted: December-20-2006 at 12:08am
BJ; Keep on practicing man. I agree with the Lake, our day is coming and I could never tackle this job alone. Maybe we can get you some side work. Of-course the Lake will have to tow his boat here to central Florida to get her done.
john
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"Loud pipes save lives"
AdamT sez "I'm Canadian and a beaver lover myself"...
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Posted By: hasbeenskier
Date Posted: December-20-2006 at 9:59pm
In 1980, Correct Craft began installing aluminum cradles for the engine,(and ski pylon) No more lag bolts. One of the most ingenious things they ever did.
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hasbeenskier
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Posted By: SkiBum
Date Posted: December-26-2006 at 5:55pm
Having recently removed the floor, foam, and observer side stringer from my 87 SN I now have a much better understanding.
In my case, the majority of rot on the main stringers was forward of the engine cradle. The old stringer was very heavy compared to a new 2"x8"x16' Fir plank cut to size. Even after multiple coats of epoxy resin and gla$$. Replacing the old with wood is very difficult. It it hard to remove them. It is harder to cut them to the approximate right size. Then, it is painful to trim them to just the right fit. Once correctly installed, the boat will be ready to stand up to another 20 years of the course.
It would have been easier to cut and care out the stringers, leaving a form that could be filled with something...Seacast, 16lb foam, a mix of gla$$, foam, and moon dust, or whatever. In the case of Seacast it is tested and proven, just much heavier.
As for the secondary stringers that are made of 1/2" wood and in some cases with foam as a filler, rot is a serious problem almost everywhere. These have to be totally replaced. Hopefully much easier than the main stringers.
Bottom line, may as well stick with the wood. It is by no means easy. But, it is tested and proven, for more than 20 years on my boat.
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Bill
http://www.freewebs.com/billsboatworks - http://www.freewebs.com/billsboatworks
www.freewebs.com/billsboatworks 1987 SN Rebuild Project
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