Here’s a question for us amateur boat builders…if you lower the height of the stringer at some point in its’ run, does making it wider at that point provide the same amount of strength?
Not quite that straight forward. Typically, by cutting down stringer height you actually stiffened the stringer (especially on the tall slender longitudinals). Its now a smaller panel and harder to deflect/bend. This will translate into the hull bottom. Current designs are very careful to make sure the stringer lam and hull bottom lam have similar stiffness or something will crack, typically the stringer to hull lam tabbing.
With that outer longitudinal, I would have no hesitation cutting the stringer down but add double tabbing at those locations.
Edit: I read the rest of your stuff. That stringer lam is probably 3610 on the web (vertical) 1708 on the cap and 1708 tabbing. This boat was built during the land of 1708-3610-24oz woven baot shops so there wasnt a lot of glass to choose from. If your going to modernize it, find a uni glass for the cap, an LTM for the web and quads work great for tabbing.
Also make sure, if you cut down the stringer height, was that supporting the deck? I see capping putty on the sample you are holding so I am going with probably. You can stiffen underside of the deck if you need to.
“If you had to tell someone how good you are, then you probably aren’t that good”
Im all mixed up in this thread now haha. I cant even find it anymore but I thought you said something about lowering a stringer height. I was just pointing out that the stringer may have been supporting the deck sole.
Those stringer look maybe 2" wide, I would want the cap to fall about 1"-2" down each side of the stringer. 3" may not be enough.
“If you had to tell someone how good you are, then you probably aren’t that good”
It took quite the pep talk with myself, but I began cutting out the stringers tonight. I removed until the first bulkhead. The plan was going to cut them out completely to use as a template but plans change. The transom needs some attention before I go any further so this gives me some working room. The core was rock solid at the bottom connecting to the hull. I would say the bottom 1/4 of the stringer was in great condition but still needed to go.
As for the transom, tomorrow I am going to drill a bunch of test holes to see what is good and what is not. It seems 75% solid from what I can tell right now. If its good for the most part, I want to put a “bandaid” on it for now and tackle a complete rebuild at a later point. The bandaid being to inject the problem areas some penetrating epoxy to stiffen it up.
If its shot I will rebuild. I don’t think I am going to put a bracket on it this year. Its not in the budget and I haven’t even had a chance see how it rides first.
This leads me into my transom questions.
It looks like the cap is bonded to the transom. It starts right at the scupper and goes up from there all the way across. Do yall see an issue with cutting it out and rebuilding? I would skin it and recore.
2.In the fourth picture, can I cut the cap where the sharpie is laying? I think I will be able to pop that piece off (about a 1.5’) so I can access the rest of the transom. Since this will be easily seen, will I be able to hide this later on?
Here’s a question for us amateur boat builders…if you lower the height of the stringer at some point in its’ run, does making it wider at that point provide the same amount of strength?
Not quite that straight forward. Typically, by cutting down stringer height you actually stiffened the stringer (especially on the tall slender longitudinals). Its now a smaller panel and harder to deflect/bend. This will translate into the hull bottom. Current designs are very careful to make sure the stringer lam and hull bottom lam have similar stiffness or something will crack, typically the stringer to hull lam tabbing.
With that outer longitudinal, I would have no hesitation cutting the stringer down but add double tabbing at those locations.
Edit: I read the rest of your stuff. That stringer lam is probably 3610 on the web (vertical) 1708 on the cap and 1708 tabbing. This boat was built during the land of 1708-3610-24oz woven baot shops so there wasnt a lot of glass to choose from. If your going to modernize it, find a uni glass for the cap, an LTM for the web and quads work great for tabbing.
Also make sure, if you cut down the stringer height, was that supporting the deck? I see capping putty on the sample you are holding so I am going with probably. You can stiffen underside of the deck if you need to.
“If you had to tell someone how good you are, then you probably aren’t that good”
Here’s a question for us amateur boat builders…if you lower the height of the stringer at some point in its’ run, does making it wider at that point provide the same amount of strength?
Not quite that straight forward. Typically, by cutting down stringer height you actually stiffened the stringer (especially on the tall slender longitudinals). Its now a smaller panel and harder to deflect/bend. This will translate into the hull bottom. Current designs are very careful to make sure the stringer lam and hull bottom lam have similar stiffness or something will crack, typically the stringer to hull lam tabbing.
With that outer longitudinal, I would have no hesitation cutting the stringer down but add double tabbing at those locations.
Edit: I read the rest of your stuff. That stringer lam is probably 3610 on the web (vertical) 1708 on the cap and 1708 tabbing. This boat was built during the land of 1708-3610-24oz woven baot shops so there wasnt a lot of glass to choose from. If your going to modernize it, find a uni glass for the cap, an LTM for the web and quads work great for tabbing.
Also make sure, if you cut down the stringer height, was that supporting the deck? I see capping putty on the sample you are holding so I am going with probably. You can stiffen underside of the deck if you need to.
I don’t know how we got on the topic of shortening the stringers, but I don’t plan too. I am keeping the deck height the same. I am going to rebuild the stringers as close as I can in dimension except I am going to double the ply up.
pghill78, sorry for the distraction. I think mdaddy may pursuing a similar project and asked about shortening his stringers.
Back to your project. I’m with you on the plywood stringers. Two layers of 3/4" plywood for your stringers would lend a lot of strength.
RE your questions… the cap (inner hull or liner) would need to be bonded to the transom. If it were not, when you bolted up a motor, the flex in the inner layer (cap/liner) would likely crack it. So, you’d want a solid chunk of material from the front of the transom through to the back face.
And, as to where to cut the cap to give better access to the transom, I don’t know. I’d just avoid getting near anything that has any shape to it… like the the gutters for those rear hatches. Choose cut lines that gives you 4-6" of nice flat surface to work with when building the cap back onto the boat. For instance, the sharpy is very near a rod holder cut out. Maybe move to half way between the rod holder and the black plate (down rigger mount?) that is forward of the rod holder. In general, if you can manage it, you’re going to want to repairing the joint where it is easy to get to and easy to fair (flat).
17’ Henry O Hornet w/ Johnson 88 spl
26’ Palmer Scott project hull
14’ Bentz-Craft w/ Yamaha 25
I cut out and replaced my transon last year and I cut my deck like PS said, it gave me lots of space to scab it back from the underside. I added a 26" setback bracket with a 250 HP E tec so I wanted all the strength I could get from the deck cap, after many hours of use it’s solid as a rock! My biggest worry was trailering!
Im just trying to stay a couple steps ahead of myself so I don’t do something I can’t fix. I know I’m tired of ripping everything out. I’m ready for the new to start.
Sorry pghill78. I didn’t mean to screw up your thread. The question was thinking out loud. With all the cuts in your stinger system for fuel hose and water passages…I figure you would block the opening on the edges of the stringer by widening around the “hole” with glass/wood.
I’ll start another thread for esoteric discussion. You did get some good input by my disruption of your thread. My apologies.
</font id=“size6”>PGHILL78 IS NOT LOWERING HIS STRINGERS.
mdaddy no worries. It was still an interesting read. I’m a Mech. Engineer so it got those brain juices flowing.
I drilled some test holes tonight. For the most part my transom is has some nice dry wood in it. The bad news is, where its bad its bad. Behind where the rear boxes were is toast. Im still thinking about going with the penetrating epoxy. I think it will be a quick and painless.
Do yall have any experience with the Total Boat penetrating epoxy?
Now is the time to replace the transom.
Don’t put it off. It’ll be easier now than in the future.
As far as your stringers, you’re on the right track.
If it was me, I would make them as thick as I could, (within reason) especially at the top. It will give you more adhesion area when you put the floor back in.
Check out the rebuild that Empty Pockets did on his old High Tide.
He made his stringers wider at the top.
I got a little carried away today and forgot to take pictures. I will try to better.
I cut the rear boxes like every said. About 4-6" in front of the “kick out” in the cap. Cutting was the easy part. The rub rail fought me on both sides for over an hour. Some screws came out without a problem, others were stripped and I used a stripped screw bit. The problem came with the heads would snap off and I would have to drill them out. Very time consuming.
I then went to town on the transom. The top of the transom behind the boxes was never covered in glass so it was easy to get my pry bar in there. I cut lots of the slits with my skill saw and grinder to help it come out in pieces. The transom was wet but not rotten by any means. I could only rip out 1 ft sections at a time. I was surprised how thin the transom actually was as a whole. Three 1/2" sheets of ply. They were laminated together with some CSM. The inner skin was at most a couple layers of glass. I plan to beef this up, but don’t want to make it too heavy.
The plywood stuck to outer layer of glass which was a pain. Out came the chisel and the flapper wheel! I got half done tonight. I should be able to grind the rest of it tomorrow.
Today consisted of more grinding until I couldn’t stand it any more.
The transom was looking really good until I washed it down with the hose. The dust was getting stuck in the low spots causing it to feel really smooth. After I washed it I was a little disappointed. Which leads me into a technical question. How “perfect” do I need to get the surface? I plan on bedding the first layer of plywood with thickened resin and squeezing it against the existing skin. In my head the resin will fill the small voids and still bond well, but Im not an expert. If no one is against it I will will proceed like that. You can see a close up at the bottom.
Nice job of grinding and cleaning, looking good! Are you planning on installing the plywood one layer at a time? Good luck! When I did mine I used a lamanated structual beam 2 1/4" thick and 30" high and 8" long, cut and sanded it to fit and soaked it with epoxy twice. mixed thick creamy epoxy and coated both the wood and glass and drilled hole in the fiberglass and pulled it tight with #12 screws and washers till it cured and took the out and filled the holes. don’t think you could pull it a part with a Cat D8.
