odd crack in a 25 Seafari

[Entourage]

Don't know i never cut it up to see. The crack was about the size of 2 thumbnails and never got any worse.

[strick]

The stringers in my 25 are hollow. If the crack is inside the stringer then you are going to want to remove that portion of the stringer fix the glass underneath it and then re attach the stringer. Then make the necessary repairs on the out side of the boat.

strick

[Blue_Heron]

Be glad to, but the damage you can see is so subtle, I don't think it will show up on my camera.

Yeah, I don't expect to be able to see the damage, just want to see how the stringer is positioned.
Dave

[cdavisdb]

Epilogue:

Well, I cut away the stringer over the odd crack, had my glass guy repair it and very securely reattach stringer to hull, lots of extra glass, this thing should be bullet proof

Should be. . . . . I did another trip, 12 days to Hole in the Wall, Bahamas. Everything seemed fine, except for a a funny shudder in the hull that I mostly ignored. About December, I decided to inspect the whole thing carefully and, OH MY! Some tiny cracks on the outside where the repair was. On the inside, the stringer end was loose. Much more damage than before. the new glass was still together, but you could see damage down inside it. The new repair was glassed to the old tabbing that secured the stringer. The old tabbing was pulled loose from the hull for several feet inboard of the stringer and almost as much outboard. The stringer was just flapping around loose. Lucky I didn't sink. At that point, I knew it was something major. Glass work is not my thing, so I needed to learn fast. A panicked HELP!!! to Strick, Blue Heron and Bushwacker, who were super helpful, Thanks guys. Extra special thanks to Blue Heron, who coached me through the glassing process.

I stripped the boat, pulled the tanks, etc, and found the stb main stringer (the one that was breaking free in front) to be snapped clean off at the forward fuel tank bulkhead and some rot in all three bulkheads in the boat. Foam had been poured into the bottom of the hull and everywhere the foam touched the plywood, rot, and nowhere else. Boy do I hate foam. You could see where water had run across the top of the foam and onto the plywood. Foam was closed cell. There was a small amount of disintegrating balsa in the floors I took out to access the forward section of the stringer.. I was surprised, it felt solid.

Lots of head scratching at this point, trying to figure out why all this happened and what to do about it. Blue Heron nailed it, we think. The boat doesn't have enough bulkheads, the main stringers don't
go all the way to the deck or inner liner and the space between the two main stringers is wide. Make it worse, the forward third of the boat only has one set of stringers, the mains. It needs to have at least one additional forward bulkhead tied into the inner liner to stiffen the boat. Lateral stress from wave pounding flexes the hull up and in, eventually causing a problem. Looks like the lack of bulkheads allowed the whole forward part of the hull to flex upward, breaking the stringer at the first hard spot, the forward tank bulkhead. We suspect that Moesley's original design, which was to have a water ballast tank in the forward section, had to have had additional bulkheads or other stiffeners. Potter took all that out of the design and did not put anything in its place, so it is a very long stretch between bulkheads and no stiffening offered to the hull by bonding the stringers to the inner liner. Took almost 40 years, but it finally caught up with me. Ain't I lucky! Blue Heron's boat was showing some early signs of what looked like the same thing.

The repair:

My glass work is mostly too ugly to show, strong (I hope) but it ain't pretty. A few pics of the offending stringer and all the bulkheads just before I put the floors back in, will follow.

All the bad glass was ground out, cut the side of the stringer out, extended the stringer all the way to the forward bulkhead, then glassed the inside of the stringer to the hull, put the side back together, two layers of 1708 over the whole thing, three layers for tabbing and more on stress areas, filled both main stringers with 8 lb foam.

The three rotten bulkheads were cut out and replaced with 3/4 exterior grade plywood with 3 layers of 1708 for tabbing. I put in two new full bulkheads all the way across the hull and up to the inner liner, around and above the main stringer, done in two sections, so I could fit it into the boat, and then glassed together in the middle. One bulkhead exactly where the first crack appeared on the outside of the hull, a second where there is a vertical section of the inner liner between the bunks and the storage area. The bulkhead is epoxied and screwed to this vertical section. Both are glassed to the inner liner, but the latter should spread the upthrust load better. These bulkheads are very close together and there was still a long stretch back to the fuel tank bulkhead. Halfway between I put a half bulkhead between the main stringers, v shaped that extended up the hull to 6 inches up the main stringers. All of these new bulkheads were set on pads of two layers of 1708, 4 inches wide, with cabosil/epoxy putty to spread the load where the bulkhead meets the hull . Hopefully this will reduce the effect of the hard spots created by the bulkheads. Finally, I cut air circulation holes in the bulkheads and installed an additional low bulkhead midway between fore and aft fuel bulkheads below the tank deck to support it and provide replacement support to the hull for the foam I took out.

Decided that I wanted to check on all this work in a year or two, so I built a rim around all the deck holes and put the deck pieces back in with screws and silicone. Thankfully, oh so thankfully, the deck pieces fit back in perfectly, the hull had not shifted at all while all the bulkheads were out. I'll glass it back together after running it hard and checking to make sure all this worked.

Splashed the boat last weekend and it runs fine. Still putting cabinetry, seats, etc back together. Very lots to do before June Bahama trip, but I'm going to make it.

Word of caution for those redoing aluminum tanks. Mine were 10 years old, covered with some kind of epoxy paint and looked near perfect when I pulled them, just a tiny bit of light corrosion in a few spots. All the spots looked about the same. Figuring it was over kill, but just to be sure, I buffed them off and found two spots with deep pits. No problem with a little bit of epoxy and light cloth, but they were on the way to failure and fairly soon. Inspect your tanks very closely and make sure you have all the old corrosion gone so you can see how deep any pits are.

Choice of material led me to epoxy over polyester. I'm happy with the choice, but there was one problem. Epoxy is runny and I was using the slowest setting variety. On vertical surfaces, it would drain out of the cloth before it had a chance to set. Lots of air bubbles. The problem can probably be resolved with a faster resin, but I needed the time, so I tried mixing in a little bit of cabosil to thicken the resin. Worked like a charm, just slowed down the wetting out process a little, which was ok with me.

Every weekend for 6 months, a least 150 hours, 9 gallons of resin and hardener, 25 sq yards of 1708, gallons of cabosil,etc, etc. It all added roughly 160 lbs to the boat, most of it forward where it was needed. I took out maybe 40 lbs of heads, hoses, foam, etc that won't go back in.

Here is your chance guys. Make your Seacraft a true classic. Score an original Raritan Compact II, hand pump head with almost new macerater pump and holding tank. Free to the first true believer who gets here.

I know some of you guys actually enjoy this stuff and you have my deepest respect, but I sure hope I don't have to do this again. Still, its most perfect boat in existence for what I do. . . Guess I'd do it again if necessary.

[Bushwacker]

Connor,

Thanks for the EXCELLENT summary. I think you've nailed the root cause - if the stringers aren't stabilized with bulkheads to prevent lateral deflection, they'll tend to buckle and you'll definitely have cracking problems in the outer skin. Terry's 21 had similar problems where the PO just cut through a bulkhead, with no compensating reinforcement, to install a bigger fuel tank!

Good advice on the fuel tank too! My boat was only 3 years old when I got it, but fortunately I pulled the fuel tank right after I got it. Someone at the factory had evidently dropped a brass nut into the bilge before they installed the tank, and there was a nice deep pit where the bare aluminum tank was resting on that nut! It would have been leaking a couple of years later! I repaired it, painted the tank with epoxy, and it was still in good shape 31 years later when I pulled the tank to clean it out before I repowered.

At least SeaCraft didn't foam in the tank and provided a hatch so you can easily pull the tank for inspection. That ought to be high on the TO-DO list for anyone that buys one of these boats! And if someone subsequently foamed in the tank, get rid of that foam so it doesn't let water contact the tank all the time!

[cdavisdb]

Thanks Bushwacker. I've thanked the stars several times for the ease that Seacrafts can be taken apart, tanks, etc. I just hope we have got it right on the cause and my solution. I'll be posting an update in a year or so, after I inspect everything again.

[FishStretcher]

Sounds like I should cut thru the storage bin under the starboard bunk and have a look at mine. It has been a trailer queen for about 10+ years, so I am hoping it is ok so far. The port side looks fine, of course.

A view inside the hull, under the port bunk facing rearward. Then forward and down into the vee, with the last being one compartment forward.

[Blue_Heron]

FishStretcher,
I don't see anything in any of those pics that would make me want to start cutting access holes. If you're concerned about the boat's structure, I would do what Connor suggested in your thread, pull the fuel tanks so you can check the bulkheads. I believe Connor had his stringer problem because his bulkheads were no longer supporting them.
Dave

[strick]

4th photo down you can see where someone glassed over the old thru hole. I'd make sure that is sound as well. There is a lot of black in your bilge... Oil? or just dirt? That bulk head for the forward storage compartment looks a little rough on the bottom. May want to make sure that it is not rotten. Although it would be hard to get to that. There should be a drain hole on the bottom of that bulkhead? I'll have to check mine.

strick

[cdavisdb]

In mine, the drain hole in the forward bulkhead was very small and easily plugged. I don't see one in yours at all, needs one. The bulkhead itself looks ok so far, might be a little wet, but no sign of structural problems. You can also access it from the forward hatch under the mattresses, much more access. You might take a battery drill and put a few small holes into the wood at the base of the bulkhead. That will tell you if any rot is present. Just seal'em good when you're done.

Ditto on cutting holes and pulling the tanks. You can get a very good look at the two main bulkheads in the boat. The aft fuel bulkhead is a high probability for rot. Also look very closely at the outside of the hull where the bulkheads meet the inside. Look for hairline cracks that suggest hull stress. If present, they will probably be parallel to the bulkhead.

Did you see any foam in the bottom of the hull under the bunks? Mine was near full and IMHO part of the problem.