Repair mast step mounting core and cabin deck?

allen-deckard · Oct 17, 2015

to the best of my knowledge the new style post goes down to a solid fiberglass support that sits in front of the keel support on top of the fiberglass that the keel hits on it's down swing. Being that it's the same glass that the keel hits I'm hoping that it's fairly solid if not then I'd say it's major overhaul not just a digout and fiberglass to make it tough enough to support the keel.

If I'm incorrect on any of this then someone feel free to correct me I've been wrong before. I haven't tore mine apart to check the interior construction nor do I ever plan on doing so. Figure boat gets bad in it's bones time to get a new hull. But from my inspections this is the best construction plans I have. Again if I'm wrong chime in.

CloudDiver · Oct 18, 2015

Last night I painted out the area under the fwd port cabin seat where the keel trunk is. This pic is on the inside facing fwd and starboard. In the top corner you can barley see some of the wood that wasn't covered by resin, but the corner is peeking out. I said it was a 2 x 4, but it may actually be either a 4 x 4 or two 2x4's laminated together. Anyway, having inspected this area when I first got the boat I was happy that none of this wood was rotten and that my compression post support was solid. I have also read elsewhere that this wood in C22's and other Catalina boats from this era has rotted. It kind of bewilders me how this is possible, but I'm sure there are many ways. The workmanship is glassing in and painting that support is obviously sloppy, so if you got any water in that bilge area it can creep into that exposed wood and sit for years...

Leeward Rail · Oct 18, 2015

CloudDiver said:
The workmanship is glassing in and painting that support is obviously sloppy

Yeah. Some worse than others. I've heard rumours that sometimes the production boat builders would hire temporary workers. Not sure if that's why the quality control is hit and miss.
If you check that compression post repair thread I linked, one photo shows his support had likely moved before it cured when built, so it's not just rot as a risk.

CloudDiver · Jan 31, 2016

In the pics it appears that you only have two small areas of deck rot compared to the overall area you opened up. Thats good news... just grind out those areas and put in equal size panels of marine plywood with epoxy. Some might say you wasted your time cutting out such a large panel.... I say its actually a good thing. When you go to epoxy down that panel it will be easier to keep the fair curve over a larger area, no will even notice the repair. BTW, on some other threads related to this topic... the old rule of thumb that polyester gelcoat will not stick to epoxy repairs has been debunked, with WEST System testing to back it up. So, when you get that panel epoxied back down you can repair the cut line with a $25 jar of Spectrum Gel Paste... No muss, no fuss.

CloudDiver · Jan 31, 2016

jmczzz said:
Ps. Guess I should have said those spaces are what made the deck in that big area flex when I would walk there. That lead me to think the whole area was bad, that's why the big cut> jmc

How much of a gap? I'm thinking a good buttering of thickened epoxy will take care of all that.

CloudDiver · Jan 31, 2016

How much epoxy do you have on hand? If you have more than a quart remaining don't buy more, just thicken that up with micro-fibers. If you don't have any epoxy on hand right now, you might want to try the tubes of G/10 epoxy that are pre thickened and self mix as you dispense them. Get the flavor of G-10 that is slightly flexible, it will absorb steps without cracking. That should be enough applied liberally to fill that gap and you'll have some squeeze out as you lay the panel back down.

CloudDiver · Feb 1, 2016

jmczzz said:
Cloud, (First, I know you are very busy with your school, work and projects but I really appreciate your advice.)
Practically no epoxy left. But I'm not sure I made it clear how much space I think I need to fill under the ply next to the cabin top skin. It seems like a lot to me. I like the caulk gun approach I saw when researching the "G10" you mentioned above. But all I found from a Google search was Gflex and Six 10. The Six 10 looks like a good approach but it's got to be more expensive than just mixing 105 and the filler? I will continue to research. Is there a different product than West for "G10"?

Another question: when I hauled out, my keel had some spots where the bottom paint had just come off. It was on the several areas where I had used some left over auto Fiberglass resign to fill low spots in the epoxy encapsulation. I now remember something about the two resins not being compatible. Question: what should I do to these auto resin spots on my keel to get the bottom paint to stick?

Yeah, Auto resin is polyester resin, not compatible with epoxy (usually). The industry (including West System) has debunked the myth that gelcoat (which is polyester resin based) will not stick to epoxy. With a properly prepared surface, like sanding with 80 grit, polyester resin or gelcoat should stick to epoxy just fine as long as its not a structural repair. Since your bottom paint is flaking off its obvious it didn't stick for some reason. Did you wash off the amine blush and sand before you applied the auto filler? Your only choice now is to sand off all those areas with the wrong kind of filler and re-fair with epoxy based fairing compound, prime and re-paint.

CloudDiver · Feb 1, 2016

jmczzz said:
"I don't like it but I guess things happen that way." a verse from an old Johnny Cash song.
I will do what I need to to make it right.
For the deck can I just mix 105, silica, slow hardener and get it under and around the cut out bad ply spots, then coat the top of the ply and press the cleaned up skin back down?
thanks, James

That should work just fine. Before laying down the skin I would use a Ziploc baggie like a pastry bag to squeeze in a thickened batch all the way around the edges first and let it harden (mostly); filling that in first will keep your main batch from disappearing under the edges when you press the top skin on. I would brush on an un-thickened coat of epoxy onto the raw plywood first to let 'soak in', then mix up the thickened epoxy to peanut butter consistency, that should be enough to fill the gap under the skin as you press it on, you should get some bit of squeeze out. experiment with some small blocks of plywood that will act as stops so you don't press the skin down too far. Cut those and dry fit them before using epoxy so you can just set some car batteries or other weights on the skin and it wont sink too low. Tape off all the outer edges of the skin and the deck with 2 inch masking tape so you can scrape off the squeeze out without a mess.
When you are ready, do the all the epoxy steps one after another, using a heat gun to at least speed the cure of the batch you squeeze under the edge. That way you'll have a good chemical bond and no sanding or amine blush.

hawk232 · Feb 8, 2016

man I wish that there were a way that the forum would notify you when your name is brought up somewhere... sorry I have been an absentee James!

"the void" of which you speak is (in my opinion) a result of catalina trying to churn out so many boats for so little money. It seemed pretty obvious to me that the cabin liner and cabin skin were separate parts that were glued together. the glue (what I compared to peanut butter epoxy) was missing in some areas and the 1/4" plywood simply isn't strong enough to support the weight! My wood was wet but not rotten, the flex that I had was from the void allowing the wood to flex. I also had two spots on the cockpit floor with the same problem (one baseball sized, one soccer ball sized). as if this isn't bad enough, Gene had the SAME problem with his new design boat. we both thought his cockpit floor was rotten, so one day we cut it up and there was just a void making it weak!

The way I handled the void was to use the plywood chunks. the factory core was 1/4". to make up for the void I spread thick epoxy down, seat chunks of 1/2 or 3/4" plywood (cant remember exact thickness, chunks were used to keep the contour of the cabin top). on top of this I used (I think 3) layers of 1708 biax to get to the desired strength and thickness. For the mast step itself I used all glass. I think it was like 17 layers of 1708.

I did reuse the skins, the skin is probably 4 layers of biax thick, why waste the cloth?? epoxy has excellent mechanical bonding strength and all it has to do is hold the skin down... I did bevel the edges for 12:1 though

hawk232 · Feb 8, 2016

James,

In further reviewing your pics, I am not seeing anything too bad. It looks like the only issue is where the wood is missing on the port side. for that I would just cut a chunk of thicker wood (measure from the liner up to see what thickness), bed it down in thickened epoxy, then pour some very slightly thickened epoxy around the crack (from where the new would chunk meets the old)then proceed with putting the skin back on. the rest of the wood appears dry in the photos (am I missing it). Also, this is based on me perceiving the bad area as being about a 6"x6" area.

I should also mention that (short of the extra work it takes) I think it is fantastic that you cut up such a large area. One of the things that I am most happy about in hindsight is that I took a 2" holesaw to all various parts of the boat and I now KNOW my boat has no rot... very reassuring and when taking on a project like this its only minimal extra work

The Garbone · Feb 8, 2016

When I redid my cockpit floor I used balsa. It comes in rolled sheets of cubes and if you wet it with resin before laying it in each cube is isolated from the next so if any water gets in it may not spread like plywood.

https://svknotaclew.wordpress.com/2014/07/03/fiberglass-work-just-a-bit-delayed/