Actual dimensions of Sunsport Stringers

[johnnymat]

Hi folks
I'll soon be partaking in a complete stringer job on my 87 Sunsport Skier and I wanted to see if anyone had the actual dimensions of the wood that comes out of these things.
I'm trying to come up with a viable composite option for the stringers and I've found a few products that are intriguing. Here's one that I thought might work if I could find long enough boards and perhaps fill the core channels with Seacast. 300001008.jpg
These composite boards are exactly 1" wide by 5.5" tall. I thought they might work but I'd like to hear some thoughts on how I should test them out prior to use. Most importantly, I obviously need to know what the actual dimensions of the original stringers are first.

I also had the idea of building forms the size of the outer dimensions of the original stringers, and making them out of layers of epoxy resin with 1/2" schedule 40 PVC tubes embedded lengthwise into the epoxy. It would end up as a hollow core rectangular board, looking somewhat similar to the board I have pictured above. However, I think it would be more rigid and lighter as well. I would experiment beforehand and these are only crazy thoughts right now...I'm not just going to start throwing this stuff in the boat. More than likely I will be talked into wood...but I'd really like to see if I can find a composite option first.

I guess the easiest question to start with is: If price was no option, what composite material would someone replace the original stringers on these boats with?

[michael hunter]

Stick with proven techniques and materials. The original wood stringers lasted 29 years. They were made out of cheap plywood and untreated wood. If you do the stringers in Douglass fur and marine plywood for the decks and treat them with CPES they will easily last 50 years plus. You don't have to reinvent the wheel to get a good job.

[johnnymat]

Thank you for the input Mike.
I don't know about the stringers necessarily "lasting" 29 years. The originals are still in the boat, but as far as when things failed and they began to rot...that's a different story. This is obviously a known issue with these boats, mainly due to a very poor stringer/floor design, poor materials, and sometimes shoddy craftsmanship from the factory.
That said, there are legitimate reasons they no longer use lumber in making these ski boats nowadays.

If there is a viable composite replacement, I am still leaning towards going that route. I figured I will have the entire thing apart anyway and will be taking my time with the job. I'd like to use the best materials I can while I have it opened up. Please don't get me wrong though...it's not that I'm completely opposed to wood, after all I am a carpenter by trade. I'd just rather use something else if I can maintain the structural integrity of the boat, eliminate ANY possibility of future rot, and eventually help with the resale value a bit. I think that "upgraded composite stringers" would be an easier sell than "new wood stringers done the right way", IMO.

Again, I'm not in any rush to jump into this, and if wood wins out...so be it! I'm doing lots of homework, compiling all the data, and even more importantly, the opinions of those who have way more knowledge than myself! I will make sure to put your check mark in the "WOOD" column. We'll see what the final tally comes to in a few month.

In the meantime, if anyone has them, I'd still like to get an idea of the dimensions of the boards I'll need.

[Mischief IV]

I have to agree with Mike's comments. This is what I think you should do...just do the wood stringers and do it like he recommends. He just finished a stringer job on his Comp and he is a master carpenter and mechanic. His advice has merit.

There is no need to do composite unless you have a very large budget and in that case, why not just go upgrade the boat to a '92 or newer and leave all this mess alone? 1" width boards will not good enough for the main stringers.

It will make no difference in the end if there is wood or composite beneath the floor for a boat that will only be valued at $6k - $8k if you're lucky. Mastercrafts had composite stringers in 1987 and their values are the same if not less...because it is still just a 30 year old boat.

[johnnymat]

All good points! I hope that my personal desire to go composite was not mistaken as any disrespect to those who have conquered these stringer projects before using wood. I have the utmost respect for anyone who has attempted this project before, let alone done it successfully!

What can I expect to spend in materials if going the wood route and where does the majority of the cost come from?
Mike had mentioned Douglas Fir and Marine Ply...what size are the boards that are used? Is this just 2x material for the fir and what size ply?

If these boats are originally made from a form...how much do the stringers really vary from boat to boat (same model/year of course)? Are there templates out there to rough cut these things prior to installation and then do the finish fitting in the boat?

[chris young]

Nearly everybody who embarks on this job wants to make it better than the original, and how you decide to to do that is up to you. I don't think it's a bad idea to go all composite at all. Just keep in mind when you are all finished, that it's doubtful any weight savings made over the original wood construction will make a perceptible difference when you're behind the boat (or behind the wheel).

Frankly if I was going to go composite stringers I'd just use blue polystyrene for the stringers. (except the motor mounts, then I think the pour in place stuff would be great) You don't need the strength of wood for the core as long as you put a heavy enough layup on it, and the beauty of styrofoam is it's really easy to shape, and dimensionally stable, and will not absorb a drop of water. Foam dust is annoying though.

I've been thinking about a stringer job like you want to do with Nida-Bond or the like for a long time, but I think the logistics would make it a very tricky endeavour. So I'd like to see someone else try it first LOL. If you could dig the dead wood out and leave the glass intact then the pour in place method could be a good way to go, but digging all that rotten wood out without damaging the glass might be very hard to do. You could try, and if it doesn't look like it'll go well then just change course and go with the tried and true.

Mischeif IV and Michael have excellent points though, if it's about resale value, forget it. Also I don't think there's any time savings to be gained over the tried and true glass over wood.

Good luck with whichever method you choose.

[michael hunter]

All good points! I hope that my personal desire to go composite was not mistaken as any disrespect to those who have conquered these stringer projects before using wood. I have the utmost respect for anyone who has attempted this project before, let alone done it successfully!

What can I expect to spend in materials if going the wood route and where does the majority of the cost come from?
Mike had mentioned Douglas Fir and Marine Ply...what size are the boards that are used? Is this just 2x material for the fir and what size ply?

If these boats are originally made from a form...how much do the stringers really vary from boat to boat (same model/year of course)? Are there templates out there to rough cut these things prior to installation and then do the finish fitting in the boat?

I used 2x8 and 2x6 fur on my comp, every stringer had to be custom cut and scribed to the changing angle of the hull from front to rear. The factory got them within an inch and covered them with fiberglass. I managed to get them within 1/4 inch and then fill the gap with epoxy. Keep in mind the major flaw in the design was the lac of scupper holes between the primary and secondary stringers any water that got in couldn't get out . Add the fact they used open cell foam that absorbed water like a sponge. Its surprising they lasted as long as they did. Some good material suppliers are U.S. Composites, Inc‎ and www.rotdoctor.com both have excellent products and helpful advice with your project.

[johnnymat]

I used 2x8 and 2x6 fur on my comp, every stringer had to be custom cut and scribed to the changing angle of the hull from front to rear. The factory got them within an inch and covered them with fiberglass. I managed to get them within 1/4 inch and then fill the gap with epoxy. Keep in mind the major flaw in the design was the lac of scupper holes between the primary and secondary stringers any water that got in couldn't get out . Add the fact they used open cell foam that absorbed water like a sponge. Its surprising they lasted as long as they did. Some good material suppliers are U.S. Composites, Inc‎ and www.rotdoctor.com both have excellent products and helpful advice with your project.

So did you make any videos or take any pictures when you did your project? Would love to see them if you did!

[Jetlink]

So did you make any videos or take any pictures when you did your project? Would love to see them if you did!

Look here...https://forum.supraboats.com/showthr...-Has-Gone-Awry