Stringer question and opinions on it pls....

[blkvyyper]

Hello to all on the forum,
I'm new to all this and i have read and reviewed a lot of good threads and admire all of the experts on this forum. My question is this... I noticed that the stringers are installed and then glassed over. Is there a reason why the stringers aren't totally glassed first and then installed? Seems it would be a stronger bond (glass to glass) to the hull versus just having the sides and tops of the stringers glassed...just something i was thinking about...all opinions are welcome.

thanks...
blkvyyper

 

[produceguy]

Re: Stringer question and opinions on it pls....

I would think you would still need to tab in the stringers even if you encased them first. This would give it more stability than just glsing the bottom of the stringer to the hull.

 

[blkvyyper]

Re: Stringer question and opinions on it pls....

thanks produceguy for the reply, i left out the tabbing part, i assumed people would understand that needed to be done. my question i guess is more toward waterproofing. it just seems no one totally encases the stringers before they install them.

blkvyyper

 

[ondarvr]

Re: Stringer question and opinions on it pls....

If done correctly the two methods would be about equal in waterproofness.

Pre wraping only puts glass in one area that isn't covered by putting them in naked and covering them, and that's on the very bottom.
If you set them in putty or a bedding compound then this area would be covered, but maybe not as well. Resin coating the bottom well would help.

The main reason for failure is unsealed holes, uncovered wood, or just sloppy workmanship.


Wrapping them first requires much more work, so is rarely done.

 

[Woodonglass]

Re: Stringer question and opinions on it pls....

Well BV, That's exactly what I do. I put the first coat of resin and CSM on the stringers outside the boat layin on sawhorses. When dry, I place and tab them in with another layer of CSM and then One or Two layers of 1708. Here's a drawing of how I do it.

Click the Pic To Enlarge

 

[ondarvr]

Re: Stringer question and opinions on it pls....

On a 16' foot boat it should take about one hour per stringer to do all of the glass work, less on many of them depending on the stringer height.

This would include the fist layer of CSM and two layers of 1708 or similar products, they would all be done at the same time.

To pre-glass the wood will take that much time or more just to apply the CSM, nothing wrong with it, but i would rather not mess with pre-glassing and do it all in one shot. It may just be my production based mentality where man hours are at a premium.

 

[blkvyyper]

Re: Stringer question and opinions on it pls....

thanks woodonglass, ondarvr, produceguy for all your comments. my boat, hopefully will be done over the winter so i have time to preglass, not in a hurry until next summer anyway. i like the idea that woodonglass does in his pic, just seems to be more water tight to me, but all of you are the experts, this is my first rebuild. Call US Composites today and the guy said that the only problem would be if water did work its way into the stringers, it would have no where to go and accelerate rot. But i'm thinking that if its sealed as woodonglass suggested in his way of doing, water should never reach it. my next problem is whether to go with poly or epoxy, i dont know the difference in the two accept from what i've been reading here in the forums. Since the boat is a 1976 procraft, the guy at US Composites said it was made of poly with woven roven or something like that. He suggested glue with epoxy and glass with poly.

Here is a link to what i'm getting into if you want to see it...http://s1238.photobucket.com/albums/ff491/blkvyyper/



once again, all your comments are greatly appreciated....

blkvyyper

 

[blkvyyper]

Re: Stringer question and opinions on it pls....

my stringers seem to be made of 2x4's,and a 2x6 or 8 down the center (keel i think you call it, sorry if i'm wrong)...would this be better to go back with the original or redo it with plywood stringers, i can get 16ft, 2 x whatevers all day long, with plywood, scarfing would be in order and i've never done that.

thanks again....

blkvyyper

 

[Woodonglass]

Re: Stringer question and opinions on it pls....

You can use Douglas Fir 2X material if you want, but most use laminated Ext. Grade Plywood to get the 1 1/2 inch thickness. That would also be my recommendation. Stronger and more resistant to rot. IF you ever do have a water issue. Buy it early and get it in the garage to dry and acclimate.

 

[Outback Jack]

Re: Stringer question and opinions on it pls....

On a 16' foot boat it should take about one hour per stringer to do all of the glass work, less on many of them depending on the stringer height.

This would include the fist layer of CSM and two layers of 1708 or similar products, they would all be done at the same time.

To pre-glass the wood will take that much time or more just to apply the CSM, nothing wrong with it, but i would rather not mess with pre-glassing and do it all in one shot. It may just be my production based mentality where man hours are at a premium.

Hahahaha I am glad I don't work for you it takes me that long to get a measurement and cut out my product and get it laid out and in position for the job and get my product measured and ready to go .

Cheers
Jack

 

[blkvyyper]

Re: Stringer question and opinions on it pls....

thanks woodonglass, i'm gonna look into the material in the near future. another question i have is it feasible to tie your stringers into your transom. Using transom braces when the boat didnt come with it. I was following WestTexasRepublics build and i like how he braced his transom to distribute power more evenly through the hull, was thinking about some design for mine similar. also have a question of this floatation foam. I understand it is used for structural rigidity and all and it comes in different pounds per cubic inch. what i'm not understanding is does it raise your boat's waterline or does it just keep it from sinking in the event of a full hull breach. my boat sits way to low in water for me in the aft section. Dont know if its because of the heavy foam and waterlogged wood or if it was designed like that. Would like to raise or is it lower the water somehow. Raise the aft end of the boat higher out of the water i should say.

Thanks to all you experts,
Blkvyyper

 

[ondarvr]

Re: Stringer question and opinions on it pls....

You can tie the stringers to the transom and put knees in if you want to, it won't hurt anything. It may not help either though, if it didn't fail in the first thirty years of life they were most likely are not needed.

Adding foam (any type) only adds weight to the boat and will make it sit lower, it only helps if you are sinking.

Your boat may sit low from waterlogged foam, weight from the motor, or just designed that way.

 

[Yacht Dr.]

Re: Stringer question and opinions on it pls....

I looked at your pics .. sure you dont want to decapitate it ? ..

The rebuild would be much more efficient if you took the cap off

OH.. and yes I like to "prep" my stringers with resin and a layer of mat before I install them ( If the primary bond fails its easier to grind and re-prep on a few saw horses then in the bilge .. ) .

Its too labor intensive for a factory to resin coat/glass encapsulate/prep for install. Normally the factory is just screwin' and gluin' .. ( they are betting that you will sell or damage your boat before it fails for mid range boats ).

YD.

 

[ondarvr]

Re: Stringer question and opinions on it pls....

Hahahaha I am glad I don't work for you it takes me that long to get a measurement and cut out my product and get it laid out and in position for the job and get my product measured and ready to go .

Cheers
Jack

After 40 some years of doing it on a daily basis you tend to streamline the process and cut out all of the non-essential steps.

 

[ondarvr]

Re: Stringer question and opinions on it pls....

I can see where pre-glassing large bulkheads or very tall stringers would help, in these situations the entire laminate is put in place before being installed in the hull, but on a small boat I see no benefit in pre-glassing when the tabbing will be covering almost all of the stringer anyhow. You end up doing the same work twice. Also if it takes time to install the stringers and they sit around for very long, you need to grind the entire surface before you glass them in place.

 

[Yacht Dr.]

Re: Stringer question and opinions on it pls....

I can see where pre-glassing large bulkheads or very tall stringers would help, in these situations the entire laminate is put in place before being installed in the hull, but on a small boat I see no benefit in pre-glassing when the tabbing will be covering almost all of the stringer anyhow. You end up doing the same work twice. Also if it takes time to install the stringers and they sit around for very long, you need to grind the entire surface before you glass them in place.

I would Never lam the stringers/bulks before installation .. I just "prep" with resin and 1 layer of 1.5 oz mat... then you Must grind the surface of your "prepped" stringers/bulks before the install/lam/tab.

Its real simple.. some buy MG ply ( I only use Marine Grade ply ) .. some buy EX grade AB,CDX etc. When you start to Lam your ply you might encounter some delam on your primary bond ( Mat ).

We are trying to Install wood panels..reinforced with plastic and fiberglass. We want the wood protected as much as possible. We also want the Bond from wood to glass to be compatible for both substrates ( wood and glass ).

Glass on glass is easy .. woodonglass .. well he is a member .. .. but I mean Wood To Glass you have to make Both Primary bonds the best you can.

I dont care if its a huge stringer job .. or a large bulkhead your doing .. you have to Prep your wood regardless ..

We have to make our plywood up to standard to accept resin and bonding on both sides.. ( again with the compatibility from wood to glass ) .

You will know if you have a chunk of wood that you want to glass in your boat if its Ready or Not .. .. or just post some pics ..

Bottom line here .. Always Prep your ply/lumber before your install. Make that wood into glass compatible before you mix up your tabbing resin and glass IMHO ..

YD.

 

[ondarvr]

Re: Stringer question and opinions on it pls....

It's standard practice to put the entire laminate on large bulkheads and similar items before they are installed, the ease and quality of the layups are higher than trying to do it vertically in a confined space. Most builders use very large tables to make flat panels for this purpose, some use peel ply and others sand the surfaces where it will be tabbed into the hull. These are typically cored, it can be wood, foam, honeycomb, etc and are infused or bagged.

These methods and practices are very different than what?s need for a one off, 16? hull that has 12? long stringers that are 6? high.

While there is nothing wrong with pre-glassing the stringers on a small boat, there is no real advantage in doing it either, it just adds time.

 

[blkvyyper]

Re: Stringer question and opinions on it pls....

Thanks to all your replies,
wow you guys are something else, really want to thank you all for your expertise and taking time to converse with the "rookie" of the bunch.

Yacht Dr. - i would love to take the cap off, problem is i dont know how, havent figured out how to get the engine off yet. The rub rail is this blue nylon chord and i see screws in it, thats a pain in itself trying to find them and remove the nylon. I was thinking of just leaving that on and cut an outline around the casting deck, and other pertinent forms inside the boat and removing that. my theory is that by leaving the cap part of it on, it will keep the hulls shape since i read the horror stories of hull warp and getting the cap back on. Then glassing the cut outs back in place once the stringers and transom are redone.

I also took a close look at the sides and aft area from the inside and seem to have some, i guess thin spots where i can see light coming through but no breaching, guess i'm gonna have to glass all the inside of the boat and reinforce that or should i just glass the thin spots? since i dont know how many of them there are, was thinking of just redoing the whole inside of the boat to be safe. I think it may be coming from rubbing on the trailer loading on and off over the years.

So floatation foam adds weight and keeps it from sinking, any ideas on how to raise it up in the water? Trying to go light as possible with this boat or make it lighter i should say yet hold more weight.

I'm hoping it was just all that wet foam and a water logged wood that is adding all that extra weight and making the boat sit lower.

 

[Yacht Dr.]

Re: Stringer question and opinions on it pls....

Normally if you dont have fiberglass coated on one side you will be able to see daylight through it ( especially on smaller thinner boats ). If its not damaged then dont worry about it .

YD.

 

[blkvyyper]

Re: Stringer question and opinions on it pls....

yacht dr.. thanks for the reply,
just seems that water would "seep" through it, am i wrong? i trust what you say, your the expert i'm not, just asking. I'm caught between the proverbial "use foam or not use foam", some say do, some say don't geez. i was thinking of using insulation foam from HD. my question is i read where you can "seal it" with epoxy resin or glassing it, do you think this is a good idea? i think it would be lighter than that pour foam stuff and i plan on putting it everywhere i can fit it, what is your opinion on this?