Stringer repair question

I just bought an old boat, a 1965 16' Slickcraft. Before taking it out on the water, i tore up the floor to check out the hull. It looks like there are some problems with the stringers. This is a $600 boat, and i'd rather not go overboard fixing it. I just want it to be strong enough to not sink or break in half. It doesn't have to be perfect, or last forever.

There is some rot in the stringers. One in particular looks pretty bad, the rest have a little rot on them, mostly in the top couple of inches, where screws were run into them (i chunked most of the bad stuff off with my hand). The one bad one looks like the bottom might be rotten as well. The stringers are not fully encapsulated, the fiberglass only goes about halfway up the wood. Most of the fiberglass is peeled away from the wood.

The transom appears to be okay. however, i don't really know. Is there a way to really tell how good/bad the transom is, without tearing it apart?

For the stringers, what would be the best, most inexpensive way to fix the problem? I'll be doing the labor myself, but material cost is important.

I was thinking of just leaving the stringers in there, or replacing the worst one, and fiberglassing them all back in. I was thinking about fully encapsulating them, and counting on the fiberglass to make up some of the strength lost in the wood. I was also thinking i'd use some of that epoxy stuff that is supposed to soak into rotten wood and "fix" it.

In addition, i'd like to fill some of the voids in the hull with foam. The area underneath the engine (which is mounted to the transom, not the stringers), as well as the sections outboard of the outermost stringers, have no real way for water to drain out. I was thinking about getting some 2 part foam to mix up and dump in there. The goal would be to keep water out, and add flotation in case the boat does get swamped. What kind of foam should i use, where should i get it, and is there anything i should know before working with it? Is there a foam i can get that will add some structural integrity?

The boat is powered by a 4 cylinder engine, and i plan on using it on lake St. Clair. It won't be going very fast, but it will see rough water and take a bit of a beating. I want to make sure it's solid before i take it out.

Any help would be appreciated. Thanks in advance.

 

Also, what type of fiberglass should i use when i work on the stringers, either encapsulating what's there or replacing them? What kind of resin? Epoxy?

Thanks

 

Another, much more simple idea. What if i just glue the fiberglass that has peeled away from the stringers, back on the stringers? How strong is 5200? Then i'd fill it with foam. Think that'd get me a couple of seasons?

 

Hello Sleeper,

If the stringers are wet and you put epoxy on them, you just seal in the water. If it were my boat (and I didn’t want to spend a whole lot of money), I would dry the stringers out, then put a couple layers of biaxial fiberglass tape over them - using epoxy. We have all the supplies you would need, it would probably cost less than $100. The alternative is to rip the stringers out and rebuild them, and it doesn’t sound like that makes a lot of sense here.

Joel Shine
boatbuildercentral.com

 

Hey sleeper,

We have run across the same problem, we bought a 75 saf-t-mate commodor for 400 bucks and planned to replace the rotted floor. When we got the floor out we found that the foam was soaked so we took that out also. Now were down to the hull and the stingers and the stringers seem pretty solid but they've got a little bit of surface rot. The sealing fiberglass is also peeling off. What we've decided to do is to take a piece of new lumber, (were using cedar but don't know if it's the best option) seal it, and then sister it to the old center stinger to add support and strenght in case the center one is weaker than we think. We are planning on sistering it with stainless or galvanized screws that go form the stinger side of the assembly into the new lumber, we plan to put big 2" washers on the screws so that it holds it tight. Don't know if this helps, that's our idea though.

commodor

 

Commodor,

If the bolts you use are going to be sealed up in fiberglass/resin, dont use stainless steal. Stainless is only good if it exposed to oxygen. Good luck.

Joel

 

Joel,

Thanks for the hint, we just got it put in and we used galvanized washers and ended up using coated deck screws. For the floor what type of plywood do you think should be used, we know we can't use wolmanized because the resin won't stick and we don't want to spend as much as mdo costs so do you think we could get away with with outdoor grade plywood? Also to be cheaper on foam prices we're using pink foam from home depot. It's closed cell and it's easy to cut and fit. And for 20 bucks for 5 cf we thought it was a deal. Thanks again.

commodor
jon and ted

 

If it were a nice boat you were going to use for a long time, I would say use marine grade ply or foam core, but in this case any exterior grade will do, just make certain it's all sealed in epoxy! I dont believe in spending a lot of money when you dont need to. On the other hand, I am in favor of sparing no expense when it comes to building something you want to last. Best of luck

Joel
Boatbuildercentral.com

 

Hello Again
What type of epoxy should we use to seal the floor and where can we get it. How should we apply it. Thanks for all of your help. Also, what type of fiberglass should we use?


commodor

 

We have a few tutorials at www.boatbuildercentral.com that will help. We also have several brands of epoxy and fiberglass. If you send us a couple digital pictures, I can get our designer to look at them a specify a lamination schedule (we do this for free when people order their supplies from our store).

Joel

 

Thanks for the help guys.

I'm going to get some boards and put in some sister stringers, through bolting them to the original ones. I'm going to put some 5200 in there too. Then i'm going to fill the whole thing with foam of some sort, then screw down some plywood. Probably going to use cheap stuff for the deck, and i don't really plan on coating it either. I may paint it, though. I figure i'll just use cheap enough plywood on the deck that i can rip it up and toss some new stuff in there if it starts to go bad, plus, i'll do it in such a way that i can more easily lift it up to see how my stringer repair is holding up. I'm going to be using a 16' boat on a lake where 3-4 foot waves are common, so i want to be able to check periodically to see if it's about to fall apart on me.

Does anyone have any pointers on how to check out the transom? It doesn't seem soft or rotted but it's all glassed in, so i can't really tell.

 

Sleeper,

You can try a couple of things, The wood boat trick of poking around with an ice pick at the the bottom on the inside of the transom. Or on the exterior, take a box wrench or something like an adjustable wrench and tap on the the entire transom with the handle and listen for hollow spots. My last fiberglass boat had a few spots. I never got as far to repair them though. I know that someone out there has a much better method than these. Just dont forget the life jackets.

Good Luck,
Kyle

 

I tried knocking on the transom a bit, and didn't turn up anything. I'll try that some more. I'll also make sure i use enough foam to keep the thing afloat in case there's something there i miss. And lifejackets are a must, as well as an oversized bilge pump and some flares.

thanks again guys. i'll post how it comes out, maybe toss some pics up too.

 

Sleeper....... do it RIGHT the first,and last time!!!!

 

Solve the water problem first then sister up with cedar boards. They are light and weather resistant and would be quick and fairly cheap.