Holes in the hull

[bmcminn]

My plan this week had been to reseal the lazaret hatches then see if I just needed to replace them, stbd in particular has been leaky. But after learning a little about this core stuff and reading a post Bob wrote about hatches I realized there might be a bigger issue. Sure enough, it's soggy wood around this side and I'm sure the other too. I'm hoping that with these I can simply dig out to 'dry enough' and then fill with expanding foam, then epoxy. There is a small leak on the bow hatch and I had thought I'd pull it and reseal also, now I'm wondering if it's going to be core damage as well. And what about around the rub rail and windows?!? Ugh. Rub rails. Ugh. The rest I'm guessing is less a big deal if the glass is not springy. I'll order a PMM tonight.







I slid the stbd gas tank out of the way and my rough guess is the outside hole is about where the sharpie is, but there's nothing showing from the cockpit and it feels solid. I really want to do this from the outside, that's why I made the bonus holes. But I can see how going from the inside is structurally preferable. Rats. I'll see what the folks at the factory say. This is the hard way to learn how to make an Alaskan bulkhead.

I'll keep everyone posted. Thanks for the info.

[bmcminn]

Here's a picture of the littlest helmsgirl, just to keep it light.

[localboy]

The wet balsa can be removed with a router bit in a drill. Remove it until it’s all dry, good wood. Hopefully it will only be an inch or so, max. Then wet the wood with epoxy resin followed by filling with thickened epoxy immediately. I’ve used West Sytems with hi density filler mixed to a peanut butter consistency. Once it goes off it’s hard as rock. Then re-bed the new hatches with something like 3M 4200/4400.

There shouldn’t be balsa around the windows or rub rail. Just glass. The balsa is only used in the bottom of the hull, roof, bow where your v-berth hatch is, top of the gunwales etc. the sides of the hull/cabin are just thick fiberglass, so you should have no issues with rot associated with windows. The bow hatch yes...like the lazarette hatches, is possible if it leaks.

Even the hole for our anchor windlass (rode) was exposed balsa. I gouged it out and used the thickened epoxy there too. Basically anywhere water can get into the balsa needs to be sealed off, or rot is possible. Even the screws that hold your fuel tanks down in the cockpit should be drilled oversized and filled with it. Same with your bilge pumps screws in the cockpit. The factory was less than thorough in this aspect of the builds. Here are pics of the same issue we had our our boat, just a different spot. You’ll see how I “gouged” out the rotted balsa and re-filled it all with epoxy. http://www.c-brats.com/modules.php?set_albumName=album2829&op=modload&name=gallery&file=index&include=view_album.php

Your daughter is beautiful.

[thataway]

It certainly will be interesting to see what the "Factory Guys" say about this. While you are at it, ask them why they don't prevent these failures by putting solid core in the areas where any hole is drilled into the balsa core. This is not a problem unique to C Dorys. A very few builders have always put in solid glass or other solid core materials where any hull penetration is placed.

A few years back when a NDT scientist and my self were developing instrumentation to test core moisture and delamination, we cut up 20 hurricane damaged boats (Chain saw and skill saw) to do both testing and documentation. Some had no damage, but no penetrations. The ones which had solid core material (only a very low %) had no core damage. The instruments were never taken to market, since surveyors and most manufacturers didn't want to spring for the $2,000 for the instrument or take the time to learn a 21st century technology.

Please don't let anyone talk you into doing a repair on that boat from the outside. There are multiple reasons that it can be an issue down the line.

Expanding foam might work for a few very small areas--but I would not use it where you propose. It is not a barrier, and can absorb water. The balsa core damage will be limited, and as Local Boy says, rout out the core, (I prefer a Dremel tool, if necessary, get a flexible shaft, I have one which is only about 3/8" diameter, and will fit way back into core if necessary). I feel that the Dremel bits give a cleaner result, and are easier to control. However even an Allen wrench can be used, as well as a bent coat hanger.

I make my peanut butter consistency epoxy mix a little different. Paint in the neat epoxy to coat the balsa and sides of the glass above and below. Any screw penetration into a cored structure (deck, floor, or hull) should have an epoxy plug. The 22's have a core in the aft cabin bulkhead, but as noted all of the sides of cabin and hull are solid glass.

Keep us appraised of the work!

[bmcminn]

OK, I'm going to do this myself. I want to see the core myself and I figure I can learn something new.

So I'm going to cut from the inside. Any reason not to go ahead and take one of those holes all the way through so I can find a corner?

[South of Heaven]

Don't freak out sir. The cockpit sole and the cockpit steps of my 25 were both compromised and had rotted core inside. Initially I was scared (and pissed!!) but upon further review I determined that the rot had not spread very far from the initial "holes".

You can definitely DIY it yourself. Take your time though. Don't skip any steps....

[thataway]

[localboy]

[bmcminn]

Oh man 5/8" would be great. At least on the lazaret hatch a lot of it was wet back to 4" or 5". I just went at it with a long flat head screw driver until I was pulling out dry bits. In a few parts of the circumference it was nice within a 1/2" or so.

I'll start to re-epoxy this area tomorrow. If I finish it with 4400 do I still need to apply gelcoat around the inside edge?

[san juanderer]

Frustrating right ! That the manufacturer would cut/ exposing the core material and NOT seal it correctly. Painting gel coat over the edge is NOT doing a proper structural seal.
What other short cuts might they be taking ?
Out of sight, is out of mind!

[localboy]

[bmcminn]

I pulled up some of the sole and the core is really wet. I've already got about a square foot. I'm going to keep looking until I get to some reasonable level of dryness and then I'll update with the situation re: the cockpit sole.

With the through holes in the hull I was recommended to use Gray Marine Tex instead of epoxy. It is expensive but I guess works well. The guy at the store however seemed uncertain about using it with fiberglass CSM. I had thought to use it just like epoxy (i.e. clean hole, fill hole, make concave, small diameter CSM and goop, big diameter CSM and goop, goop, sand, and glossy stuff) and figured the added thickness would help to hold upside down. But I'm going to wait to open it until someone (i.e. doc or localboy or micah - thanks!) chimes in.

With the lazaret, man it goes back so far that I really want to use expanding foam to within 3/4" of the edge and then finish with epoxy or Marine Tex.

OK. Except now after reading a bunch of stuff on Hull Truth, I'm going to go back and buy a bunch of epoxy and associated supplies. I think the guy just upsold me.

But I'm not going to open anything until I see what you all have to say. Hope you're having a good day!

[Micahbigsur@msn.com]

I like to make up my own West epoxy filler with a mixture that suits my present need, just an opinion, but I would use for a strong mix, high density, a bit of silica (for thixotropic, no sag properties) and microfibers. For a smooth finish leave out the fibers. No easy sanding micro-balloons below the waterline.
Good luck.

[localboy]

Can't say not to use the expanding foam finished off with thick epoxy, but I have limited knowledge and no experience using it. There was a poster on TF that used it on his deck of his 30+ yr old Taiwan trawler. It wasn't just the Home Depot stuff you purchase for sealing windows etc though. It was this stuff: https://injectadeck.com/

[bmcminn]

OK That inject a deck looks interesting because...







However, there's no part of the deck that feels soft or squishy at all. I don't really know what to do. You can see where the core is just mushy junk that I can pull out vs more solid but still wet material. So do I fix the holes in the hull, throw a piece of plywood on this, fish through January, and then pull the entire sole later this spring?

Or do I get a PMM and search for more rotten core, drill, and use that crazy inject-a-deck.

Right now I'm gonna use some saltwater to do some brining. Back here later.