Solid fiberglass stringers?

zachgry · May 31, 2009

I was looking at another post about a guy who had thought his stringers were fiberglass with no wood and it got me thinking. Instead of glassing wood stringers in your boat why not just use fiberglass boards and glass them in instead. We all know that no matter how well you try to keep water out of the stringers eventually water will find a way in and rot them. So you guys that have been doing this awile please tell me if it would be a good idea or not. The only downside i see is it might be a little more expensive but if it would work you would not have to worry about rot anymore. Again the fiber boards might cost more but you would not have to use so much epoxy than you would if you were trying to seal wood stringers. Anyway if anyone has done this or has a thought to what the pros and cons would be please let me know.

ondarvr · May 31, 2009

Re: Solid fiberglass stringers?

It works, the main problems are cost, weight and the difficulty in shaping and working with it.

danond · May 31, 2009

Re: Solid fiberglass stringers?

That boat will last another 20+ years with a proper wood/fiberglass stringer setup. I wouldn't think it to be worth the trouble or cost in trying to outdo the original design by that large of a margin.

88BLiner · May 31, 2009

Re: Solid fiberglass stringers?

I agree with ondarvr, it would work but just cost more. I think that as long as you do a good enough job fiber glassing it will last you like 10 or 15 years. if you plan on keeping that boat that would be great, but if you may get another boat with in 10 years or so I would not waist the money.

jonesg · Jun 1, 2009

Re: Solid fiberglass stringers?

pvc tubing , wax and mold it, remove pipe ...install and glass over it, the strength is in the glass and its shape.
My main keel stringer is a glass half pipe.
Taller stringers are probably more conducive to properly prepped ply but can be done with composites if you can afford it.

coastalcruiser · Jun 1, 2009

Re: Solid fiberglass stringers?

I glassed up some fiberglass stingers, Just take some wax paper and layer strips of matt and resin then put it in place. peel off the wax paper.

109jb · Jun 1, 2009

Re: Solid fiberglass stringers?

Sure you can do solid fiberglass stringers. The problem you will run into is that if the stringer has any height to it you will have to make a thick laminate in order to prevent buckling in the vertical direction. You can reduce the thickness of the laminate by making the stringer corrugated like a pickup truck bed. Stand the corrugations vertically to increase the buckling resistance. Accatched is a quick drawing of what I'm talking about. You could make a form out of wood covered with a release of plastic, wax paper, or I have even used plastic packaging taped for a release. You would then have to devise a way to attach the deck to these stringers. I thought about doing exactly this on my Sea Ray I'm working on, but decided that even with the original wood you are fine as long as you take proper care of the boat. I have a friend who's dad bought a Sea Ray new and then handed it down to the son and that boat is as solid and looks as good as the day it first came home because it was and is still well cared for.

salty87 · Jun 1, 2009

Re: Solid fiberglass stringers?

why not if cost is not an issue. most people have more time than money and plywood suits those purposes real good.

also, you need to examine what caused your OEM deck and stringers to fail. was there any drainage at all? a few well placed limber holes might be just as effective and much quicker/cheaper than composite stringers.

coastalcruiser · Jun 1, 2009

Re: Solid fiberglass stringers?

Sure you can do solid fiberglass stringers. The problem you will run into is that if the stringer has any height to it you will have to make a thick laminate in order to prevent buckling in the vertical direction

I used a ply 1x4 on the top of the stringer, then glassed overtop to solve that problem

also, you need to examine what caused your OEM deck and stringers to fail. was there any drainage at all?

If you dont have drainage the water gets trapped. I put drainage in all my cavities

ondarvr · Jun 1, 2009

Re: Solid fiberglass stringers?

The way it's typically done is to just pre-make (in a mold) hollow fiberglass stringers that get set in the hull and glassed over, light weight and no rot, easier to do in production than in a one off application, but it can still be done.

Yacht Dr. · Jun 1, 2009

Re: Solid fiberglass stringers?

You cant have hollow strings m8..

I wont go into uscg rules..but its a no no..

YD.

Yacht Dr. · Jun 1, 2009

Re: Solid fiberglass stringers?

the form is the form..the glass is the glass..as long as the glass does not freeze..then the composite is the stringer system..

does not matter if foam..or wood..its only a shape for the composite stringer .. ( let the wood rot ) as long as you dont have water expansion..

YD.

PS. love to have Bondo back me on this huya

ondarvr · Jun 1, 2009

Re: Solid fiberglass stringers?

I know nothing about the C/G rules on hollow stringers, not my part of the process, but I do know boats are made with them. Pre molded stringer grids that are bonded (glued) in place before the liner goes in. Some are glassed over and some aren't.

I'd like to see that reg if you have it handy.

ondarvr · Jun 2, 2009

Re: Solid fiberglass stringers?

I talked with a couple of friends that own boat building companies, plus do the design and engineering work on their products. They said they've never heard of a regulation saying that stringers can't be hollow.

Please supply the information on the rules you're talking about.

drewmitch44 · Jun 3, 2009

Re: Solid fiberglass stringers?

Yacht Dr. said:
You cant have hollow strings m8..

I wont go into uscg rules..but its a no no..

YD.

I dont believe this at all. If that were true then why are manufacturers doing it every day? Like was stated above i would like to see that reg. if it exists. At this point i do not believe it at all. I have been wrong before but i just cant see big companies breaking laws in their construction of boats.

69starcraft · Jun 3, 2009

Re: Solid fiberglass stringers?

I don't think thats true either.

The stringers on my boat are hollow per design (1968 Glaspar Avalon)
I was surprised, expecting to find wood or rotten wood but when we replaced the transom we found no wood in the stringers at all.

I think thats why the floor of my boat is so solid to this day.

Yacht Dr. · Jun 3, 2009

Re: Solid fiberglass stringers?

Hello m8s..

I didnt think I needed to but..here it goes..

Guided under US code Title 19. sec. 1703...

You cannot modify OEM manufacturing of the vessel structure ( foam filled this or that ) without risk of being in violation of this code. ( also check title 46 ).

Its not in manufacture..its in modifications.

Basically saying is if your in open waters with your DIY repairs and not putting your boat the way it was "made" "could" constitute a violation of smuggling law. It would be up to USCG to evaluate your "modified" reconstruction.

I just talked to a SGT from USCG in CA. and he said " Its hard to evaluate every constructed vessel however the CG can evaluate your boat.. and if has reason to find a modification that could be considered as a smuggling compartment you could be subject to US code Title 19. sec. 1703"...

He basically stated that DO not mod/change the design of the boat without getting it certified. ( he said it was free..but I/you will check on that ).

YD.

ondarvr · Jun 3, 2009

Re: Solid fiberglass stringers?

Yacht Dr. said:
You cant have hollow strings m8..

I wont go into uscg rules..but its a no no..

YD.

So the C/G has nothing to say about hollow stringers, they don't want hidden smuggling compartments, that could be considered anything on a boat, like a hollow seat base. I don't think anyone here needs to worry about that regulation.

Yacht Dr. · Jun 3, 2009

Re: Solid fiberglass stringers?

ondarvr said:
So the C/G has nothing to say about hollow stringers, they don't want hidden smuggling compartments, that could be considered anything on a boat, like a hollow seat base. I don't think anyone here needs to worry about that regulation.

I dont know ondarvr.. did you call up your local C/G and ask them ? ( Like I did ? ). or are you again speaking for everyone that wants to mod there boats ?

You say "anyone" here needs to not worry ? are you kidding ??

I do respect you m8 ..seriously..but..please dont give me a reason.. I gave you and other posters my Title..and you still want to spar ?? and now you want to take me out of context ?

Im saying if YOU WANT TO MOD YOUR BOAT..MAKE SURE ITS AS CLOSE TO OEM AS POSSIBLE..

Done..please dont spar with me m8..

YD.

109jb · Jun 3, 2009

Re: Solid fiberglass stringers?

Yacht Dr. said:
Im saying if YOU WANT TO MOD YOUR BOAT..MAKE SURE ITS AS CLOSE TO OEM AS POSSIBLE..

And yet in another thread where I was saying that flotation foam should be replaced during a rebuild, I was flamed for saying it. If you eliminate many cubic feet of flotation foam haven't you created a potentially huge smuggling compartment? Also, if you are recommending rebuilding as close to OEM as possible doesn't that mean replacing the flotation foam?

Solid fiberglass stringers?

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