Can I do this instead of rebuilding my boat stringers

I have a 30? boat with a flybridge that has some bad stringers and would like some comments with the idea of adding plywood to the outside of the stringer instead of totally rebuilding them. I?m reluctant to cut the original stringers off or up just because I?m concerned of warping the hull because of the size of the boat. It?s on a trailer now and supported pretty good so am wondering if by epoxying two ?? pieces of plywood on both sides wrapping this in cloth, if this will have the same strength as the original stringer? The original stringer is 2? x 12? wooden beam (not plywood). Picture 1 shows where the 2 x 12?s were spliced (actually just stapled) with a small section of plywood which had to be removed in order to run the plywood from front to back. The drawing below is what I?m thinking of doing. Any comments?

Re: Can I do this instead of rebuilding my boat stringers

Hi there,
I am wondering the same thing. I don't have a big boat like you do. I just have a 1989 Four Winns H200.
I hope for a few replies on this issue.
Thanks in advance.
Kotte

Re: Can I do this instead of rebuilding my boat stringers

As long as you realize that you will be using epoxy to seal up the rot...... the rot is a cancer to the wood and may destroy your plywood sooner.

Now..... check out nida bond or seacast and cast the stringer's in place.

Yes ....what you want to do will work but it is not recommended.

Re: Can I do this instead of rebuilding my boat stringers

Bob, thanks for the suggestions.
So is your recommendation to add the plywood for stringer support then cut the top off the stringer and replace with good wood epoxied in the fiberglass shell? Would be cheaper than seacast right? Not sure about nida bond. Just read a brief overview about it. How would this be used in this application?
Thanks again for your help......

Re: Can I do this instead of rebuilding my boat stringers

I just finished doing the NidaBond Pourable Transom Compound (aka Arjay Ceramic Pourable Compound) on the stringers of my 1988 Donzi. The wood in my stringers was originally 3/4" plywood. About 75% of it was rotted (some of it was like dirt). I cut 3" wide holes at the very top of the stringers, about 12-18" apart. I then used some long drillbits, screwdrivers, and prybars to break apart the wood. Then, using an ovalized piece of electrical conduit connected to the shop vac, vacuumed out all of the wood. Basically, I performed liposuction on the stringers The more rotted the wood, the easier the removal process was.

Then, the pourable compound was poured into the empty stringer. I used ~3 1/2 of the 5 gallon buckets on my 23' boat, with 4 stringers about 8-10' in length (again, the stringers were 3/4" thick).

I'm very happy with the results. The stringers are now solid as a rock. I tested a piece of the dried compound, and it can be drilled to accept a screw easily without breaking or cracking. This is now perfect for attaching the new deck onto, without fear of drilled holes rotting any wood.

Overall, I think it was much easier doing this than cutting out the stringers and building them from scratch (since mine were completely encased in fiberglass to begin with). Plus, it was easier than grinding the sides of the existing stringers to sister a new piece of plywood to it's side.

Re: Can I do this instead of rebuilding my boat stringers

Doesn't that still weaken your stringers if you only do part of the stinger in the nidabond? i understand the concept of doing it, but if you don't take all the stinger out it still leaves gaps of rot, or soon to be rotted wood. Im curious about that because i'm interested in using the nidabond to build my own strings/transom compound. cause i have a few boats that i'm working on. my buddy used the stuff to do his transom. and it just leaked out cause he didn't seal it all the way, but when it went into the bottom of the boat, and hardened it was like rock. we could hardly knock the stuff out. My18' cheetah ski boat i'm working on now, seems to have that as the transom right now, but the dude cracked it, and it just sorta flakes out now cause he didn't do the whole thing. so whys thy i'm asking, doesn't it weaken it if you don't do completely, and couldn't it still crack/break apart?

Re: Can I do this instead of rebuilding my boat stringers

Can someone help with informing me what type everyone is using for stringers and bulkheads? Looks like there is multiple materials so not sure which one is the right one.
Also I couldn't find any pricing. Is it similiar to Seacast price wise or cheaper?
Thanks.....

Re: Can I do this instead of rebuilding my boat stringers

Drewb082001 said:

Doesn't that still weaken your stringers if you only do part of the stinger in the nidabond?

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Why are you assuming that only part of the stringer was done? If the wood is rotted, you get all of it out. If the wood isn't rotted, and you can't drill or break it apart for removal, then that means it's still strong enough to perform it's function, and the Nidabond will fill in all around it and solidify the remainder of the stringer.

i understand the concept of doing it, but if you don't take all the stinger out it still leaves gaps of rot, or soon to be rotted wood.

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You HAVE to remove any rotted wood. No purpose in using a pourable compound if you don't plan on removing the rotted wood. The purpose is to remove the rotted wood from the inside, and leave the fiberglass shell that was around the wood form of the stringer.

Im curious about that because i'm interested in using the nidabond to build my own strings/transom compound. cause i have a few boats that i'm working on. my buddy used the stuff to do his transom. and it just leaked out cause he didn't seal it all the way, but when it went into the bottom of the boat, and hardened it was like rock. we could hardly knock the stuff out.

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Right, you have to make sure any holes and gaps are taped shut, or the material will leak out. But as you saw, once it cures, it's very tough.

My18' cheetah ski boat i'm working on now, seems to have that as the transom right now, but the dude cracked it, and it just sorta flakes out now cause he didn't do the whole thing. so whys thy i'm asking, doesn't it weaken it if you don't do completely, and couldn't it still crack/break apart?

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Anything can crack/break if not done correctly. You just have to make sure that you do a proper job.

Re: Can I do this instead of rebuilding my boat stringers

gugie said:

Can someone help with informing me what type everyone is using for stringers and bulkheads?

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What type of what? Do you want to replace the wood with new wood, or remove the rotted wood and use a pourable compound?

Also I couldn't find any pricing. Is it similiar to Seacast price wise or cheaper?
Thanks.....

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If you're referring to the Nidabond or Arjay, it is about 1/2 the price of Seacast. A 5-gallon bucket costs ~$130.

Re: Can I do this instead of rebuilding my boat stringers

I just did a Nida pourable transom, and it went super. I was able to get ALL of the old rotten wood core removed from the between the inner and outer transom skins, sanded inside (a real pain) the shell, washed with acetone, and pre-coated the inside with vinyl ester resin the day before the pour. The pre-coating was done at the recommendation of the Nida tech person. One down side of the Nida is the shipping - cost $113.00 to have 6 gallons shipped from Florida to Washington state. They actually gave me the one gallon, I just had to pay the shipping!! Their standard unit is 5 gallons.

Coho Ghost

Re: Can I do this instead of rebuilding my boat stringers

I was curious what type of pourable product everyone was using.
Going to look into the Nida product.
I'm going to go ahead and attach some plywood to the outside of the stringer to keep it strong while I get the old wood out of the stringer encasement.

Really appreciate everyones suggestions.

Re: Can I do this instead of rebuilding my boat stringers

gugie said:

I was curious what type of pourable product everyone was using.
Going to look into the Nida product.
I'm going to go ahead and attach some plywood to the outside of the stringer to keep it strong while I get the old wood out of the stringer encasement.

Really appreciate everyones suggestions.

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What are you going to attach it to? And how? Curious....

Re: Can I do this instead of rebuilding my boat stringers

Jacket4life said:

What are you going to attach it to? And how? Curious....

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I was going to glue two ?? sheets of MDO plywood together and then epoxy these to the fiberglassed side of the existing stringer. Then I can cut the top off the old stringer and remove the rotted wood without worring about the hull warping or anything. I'm still not sure if I need to remove the paper backing before epoxying these sheets together or if I can leave the backing on.

Re: Can I do this instead of rebuilding my boat stringers

gugie said:

I was going to glue two ?? sheets of MDO plywood together and then epoxy these to the fiberglassed side of the existing stringer. Then I can cut the top off the old stringer and remove the rotted wood without worring about the hull warping or anything. I'm still not sure if I need to remove the paper backing before epoxying these sheets together or if I can leave the backing on.

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So is this going to be temporary, or unltimately are you going to end up with this "patch" (for want of a better term) and some kind of new stringer in the place of the originals?

If that is so, then I think I'd glue them on, then epoxy over it, after I had remove the existing stringers and replaced them. The glue is easy to use and strong enough to give the support while you are working on the originals.

BTW, do have you or will you be removing the cap? And how is the boat supported now? Trailer, cradle, other???

Re: Can I do this instead of rebuilding my boat stringers

Jacket4life said:

So is this going to be temporary, or unltimately are you going to end up with this "patch" (for want of a better term) and some kind of new stringer in the place of the originals?

If that is so, then I think I'd glue them on, then epoxy over it, after I had remove the existing stringers and replaced them. The glue is easy to use and strong enough to give the support while you are working on the originals.

BTW, do have you or will you be removing the cap? And how is the boat supported now? Trailer, cradle, other???

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My original thoughts were to permanently epoxy the MDO plywood to "both" sides of the existing stringer, then lay some matt over everything. I'm hearing that this may not work so now thinking that I'll epoxy plywood to just one side, cut the cap off the existing 2" x 12" stringer, dig out the old rotted wood and epoxy back in a new 2" x 12". Original stinger is not plywood but just a regular 2" x 12" piece of pine.
What do you think?

I can't say enough great things about this forum! Very comforting to know that there is all this knowledge out there and people willing to share it.