odd crack in a 25 Seafari

[strick]

These pictures are from the port side which is the opposite side of were Connors crack is. I would have had to cut out the bottom of the starboard storage compartment to get any pictures showing the complete stringer and hull were his crack is located. I'm assuming that the hull is configured the same on both sides.

Looking down from the cabin door. The stringer appears to run directly over the step/chine that is cracked.



The crack is about 24 inches up from the bottom of the keel which puts it somewhere close to where you can see the end of the tape measure.



In the picture above note were the stringer ends. The chine/step extends about 16 inches beyond the end of the stringer however the crack is definitely inside or close to the side the stringer were the end of the tape is located.

A couple more shots looking aft







strick

[cdavisdb]

You got it Strick. From what I can tell, most of the crack is directly under the stringer, with a little bit extending toward the keel past the stringer. Some kind of defect directly under the stringer or in the stringer/hull attachment?

[Bushwacker]

Connor,

I think Dave's right, it's a compressive failure. Those small fore & aft gel coat cracks up in the step radius may be the result of tensile/bending stress from flexing in the flat panel aft of the vertical crack. Maybe stringer wasn't well bonded to hull in that area; I've heard of some 23 Sceptre's having problems with loose stringers, so maybe this is a similar problem.

I cc'd you on an e-mail I sent to FiberglassOne and some aerospace engineer friends with a link to this thread, so check your e-mail. Dan has seen that type of failure many times, and said you will probably see a LOT of delamination on inside. I'm guessing you'll have to cut out the inside of the storage box under the bunk to get a look at it. If your glass guy is swamped, either he or Don Herman would be good guys to fix it if you felt like towing it over this way. Maybe we could get together while you're here . . . make a weekend out of it! Denny

[cdavisdb]

Thanks Bushwacker

Either of those guys would do a fantastic job, but Palm Beach is a Loooong way from Sarasota. Still, its worth thinking about, I want this done exactly right.

[Ryank]

Best Glass guy around on this coast is Kevin Horn at american boatworks in Tarpon. They do incredible work, and he standsa behind it. He did my transom, and several others I know of.
Pretty wild link showing some of his work. Tell him you know me from the website. The cool thing is he will make a cd of the repair of each of the steps at no charge if you want.
http://www.youtube.com/watch?v=K8s-6...feature=autofb

[JohnB]

On my 23, I had a stringer come unattached (poor workmanship). I had a couple of minor gelcoat cracks but nothing like this. If the stringer is attached in one spot, but not another, it will create a hardpoint where it becomes unattached. That would be my guess.

[NoBones]

Just a thought Connor, There is the possibility that
you may have struck an object while under way and
did not realize it at the time.
Those lateral stress marks in your pic make me
lean this way.
As thick as the glass is in our boats in the bottom
it is unlikely that there was any failure in the
stringer system. If the crack was close to a bulk head
that would make more sense...
Just my .02¢ worth on this.
At least you had a good time and she still got
you home safe and sound!!

See ya, Ken

[cdavisdb]

Thanks very much for all the input. You guys are something else!

Well, I think I know why and what happened. Thankfully it doesn't look too extensive. Boy, was I thankful.

I cut the bottom out of the stb storage container to access the area above the crack. At first look, all was perfect, but on closer inspection, I found (1)the crack is entirely under the stringer (2) a small area of broken fibers in the woven roving in the bend where it attaches the bottom of the stringer to hull, about 2 inches fwd of the crack (3) the stringers are not symmetrical. The port stringer looks like it was pushed up against the vertical part of the inside strake and glassed in place. That looks right and should make it very strong. The stb stringer is attached at least an inch inboard of that, which would create lots of space between strake, stringer, hull, etc and maybe weakness in the hull under the stringer. With the stringer slightly out of place, the strake is basicly unsupported. Assuming the stringer is hollow, I can see how a compression fracture might occur.
Looks like grind out the bad glass, attach the stringer to the hull more strongly and do something inside/underneath the stringer, not sure what. Fill it with poured foam maybe? Since the entire stringer can't be filled without taking the boat apart, would that create hard spots at the end of where the foam goes?

Any other suggestions?

Thanks again

O yeah, the aft end of my stringers are hollow. I can't tell about the forward sections.

[Blue_Heron]

Connor,
Can you post pics from the inside?
Dave

[cdavisdb]

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

I made some drawings, trying to conceptualize what the problem really is, and its pretty clear. Set the stringer off an inch or so inboard and the strake is very poorly supported.