thru-hulls, delamination and fiberglass work - oh, my!

[captain crunchie]

This is what we're looking at on Augusta, Commander #303. You can see the damaged area at the waterline on the right of the picture. This one has about everythign worng with it that you might not want: the hull was punched through below the waterline, there was a bad repair and extensive delamination behind the bulkhead and on the interior of the hull and then they put a truly bad Rustoleum paint job on top of it.

We have stripped the hull of the old paint & gotten an idea of the size of the hole - next step is to tackle that problem. I'll make sure to include shots of the interior - that's where things get really interesting.

[ebb]

Looks exciting.
What are you going to do?
How are you approaching the repair?

[captain crunchie]

We're approaching the repair pretty much by the book, at least the book I've read. As the bulkhead is dry rotted, we'll have to pull that out on the Port side. The damaged section goes underneath & behind the bulkhead. Hopefully, that won't be much more than cutting the tabbing and then sanding it down behind it.

As for the damage, we've beeen sanding away until we hit true glass (not delaminated) and then angling it out at about 30 degrees. So far, we haven't even peeled away everything from the inside yet and we have a 5 foot by 1 foot area sanded away, going through 3 layers of roving and matting so far. That took about 4 hours with 40 grit sandpaper on a random orbital sander hooked up to a vacuum system. Itchy stuff all the same.

That's when the problem started looking really huge. The delaminatiion just didn't seem to have an end. So we sanded down the exterior hull and assessed it.

The next step is to sound out the bondo, find where the actual hole is and knock out the patch material. Then we sand thru on both sides (interior & exterior), until we find true glasss all around the repair. One there, we'll drill holes, mount sheet metal on the outside of the hull and start building up the repair from the inside the same way it was built: fiberglass, roving, matting, fiberglass, etc.

Once that's been done, we reinstall the bulkhead (marine ply) and start making it look pretty.
Any input on this would be greatly appreciated. It's a big job.

[CapnK]

Tilley hats off to you, captain crunchie, for giving a grand old lady a home, and the love, respect, and proper care that she deserves.

Salut!

[ebb]

Sounds pretty straight forward.
Sounds like you don't have a cave in, ie broken and semi crushed laminate pushed in. If you have displaced furniture that was tabbed in by Pearson you have a problem. All the tabbing is done on 338 on the top only with blue gobs used to hold whatever piece when the guy set it in place. So, while daunting, it can be removed. It looks like the crush was reduced by the built-ins inside, the settee? it looks like only unsupported hull was smooched.
............................But if you do have something bad......here's some thoughts............
338 is nude inside at cost of a great deal of grinding and evil dust. So I can say, the best thing to do would be to stabilize the whole wound inside with an overlapping piece of xmatt (mat with two crossed layers of oriented strand loosely sewn together.) It's easy to wet out. With a piece of plastic over it you could even apply some pressure on it with a firm cushion or something, braced from the opposite side - to get any pieces to lie flat. If there is laminate seperating, maybe just get it good and wet befor the mat goes on, that's the way to do it anyway: wet the hull, position the fabric on, wet it out with brushes.*

After it is set and dry, then you can grind and explore outside knowing the shape is stablized.
You have to grind beyond the damage zone on to good stuff all around.
What you find will dictate whether the damage has to come out, ie a hole (but, of course you have already shut the hole and more or less have the shape - so you can grind off the broken pieces. You will be finding white glass in there, which is ok, as long as it is stiff and sound.

If you were plugging a hole like a thruhull, you'ld grind a very flat taper, twice as wide as the hole, first on one side and then the other, and layer in disks of cloth or xmat that overlapped the hole smallest first and out to the largest. Four, five, six a side. Ending up with the same thickness of the hull where the hole was.

Same thing with the wound in her side. The overlapping on to undamaged laminate is very important, I think. Depending on whether you have a large hole or a small one, the overlapping and layering should IMCO be exaggerated. Depending on the hole, as much as 12." However, you can gain all the strength you need by adding extra layers inside. Tabbing the furniture back in place will create a lot of stiffning. and support.
You could even glass in some ribs.

338's hull is pretty thin where you have damage. So the overlapping outside can't be many layers if this is the case with yours. Xmatt creats thickness and great strength. Depending on the 'weight' four to six layers yeilds 1/4" thickness approximately. Can ofcourse use cloth. And can always grind it off.

You could check your curves by taking the curves exactly opposite on the port side using posterboard and cardboard, To help keep the layering within the parameters. Doesn't HAVE to be exact, later there is filling with easy to sand microballoons and longboarding.

*This xmat fabric has another attribute you wouldn't dare try with woven fiberglass. But you have to have everything marked with a sharpie and the matt cut to the shape you want. Place the mat on a flat surface that has plastic on it (visqueen, the more mills the better) Paint an epoxy puddle on the plastic, lay the piece in it and wet it out. Then peel the wet cloth carefully away, may take four hands, and slap it on the work. If you do it without worrying, it'll hardly get distorted. Use your rubber glove hands to pat the entrapped air out and press it tightly. Use a wet brush to stipple remaining bubbles out (hardly any) and to get the frayed edges to lay down. :eek

OK, Here's another.
I use cabosil alot. It is a lighter than air white dust that you mix directly in to the epoxy. I mix it in until I have 'stiff peaks' like they say of beaten egg whites. If you have an uneven surface, like I imagine your crunched side to be after you clean it up - even some edges that don't meet so good but are yet still strong - you paint raw mixed epoxy on the surface getting into all cracks, then you paper towel the wetness off. Important.
Using a spatula spread the gel over the imperfections and into the cracks, immediately lay your wetted xmatt or similar over it, as above. You could then have a nearly smooth and maybe pretty fair surface to finish off with the overlapping layers.

I use non-blushing (laminating epoxy with slow hardner) 100% solids (no solvents, very little odor) product. It means I can stop, come back the next day and continue. If I miss a couple days I just scuff it with 40 grit and continue on. My ergonomic handled Sandvic carbide scrapers cut right thru hardened glass. Mo'betta than that Makita grinder and hard lapped sanding disks whot gets trillions of nasty glass pieces everywhere and floating in the air..............man...i... been duin..... this....too long..(croak)...

[captain crunchie]

wow - thanks so much. I think that'll be a great help.

I was at the boat today - here are the result of the last sanding session. The overall damaged area - still trying to find where the delaminated glass ends. We're going to remove that bulkhead this week and we're going to consider ebb's advice as we go forward. Thanks, ebb.

The second shot give a good sense of the thru-hull hole. That's where the bondo is.

The third shot is just a sample of the all-too-familiar delaminated glass.

More to come as we go.

On a positive note, the brightwork is looking fantastic and we casted a new eyehole for the boom that will replace the connection that broke on us recently. More on that later - my partner had a very good idea.

[ebb]

Those are great dramatic photos for sure,
Wonder what caused it?
Think the boat fell? Can't imagine hitting a piling while sailing that would produce such a hickey.
Hurricane damage?

Who knows. But I was talking with another guy about your little problem, with a guy who is present at the yard every day, not like me only weekends.
He mentioned a legendary local very high end fiberglass guy had been working on a Bar Tender at the far end of the yard, that I saw come in with extreme rock damage to the underwater areas. Extreme, this hull is 3/4s to 1" thick, so I imagime there was a lot of white delaminate (roving and matt) showing once it was cleaned up. Bummed I wasn't around. Becaause....

Evidently he used a vacuum bag technique, that I know nothing about, and vinylester. Vacuum to drive the resin deep as possible in to the delaminations - and vinylester because it sets up right away and you can shape and go on to the next step. Took him two days!!!

Of course there ALWAYS is another way to get a job done - but IF you have hull shape and a lot breaking (but with good hull 'integrity') as what it looks like in your photos, vacuum bagging may be the only way to resaturate fibers deep into the structure. Don't know that anybody has talked about such a technique here, and you don't need a college degree to figure it out since so many peaple do it ---- maybe that's the way to go? My guess is the decison is based on how much fiber you have to fill, and how to get in to fill it. The applique' way described above would require that all loose stuff be dug out and ground away. Deep gouges could have chopped strand mix pressed in to them, followed by cabosilgel and mat layers. Vacuum bagging is way more sophisticated, if appropriate. Wonder how he spanned the holes?

If the breaks are essentially broken but connected shards with relatively little fiber showing AND a not so thick a laminate (3/8s / 1/2"), a variation on my last post might be easier.

I, for one, am very curious just how much damage your gelcoat removal will reveal. And what you decide to do.
Your solution, method and progress photos of such extensive damage repair will be most instructive and no doubt very well visited in the archives by many in the present millennium!