San Juan 21 Class Association

Hey,

Sad day today. Although I replaced all my through deck fittings last year and found very little dry rot and no sponge, I largely ignored the transom. Prepping for my upcoming paint job, I pulled all the hardware off the transom today. I found water in several of the holes. The balsa core seems largely just moist, only one hole had mush. I really don't want to recore the transom. i have not noticed any flex this entire year in the transom even with a 4hp engine used often. Has anyone ever tried to just drill several holes, then put a heat lamp and fan in the lazarette for a few weeks, then refilling with lots of epoxy? I will repeat, i really don't want to recore.

also, where the hell is the butt end of the rear chainplate? Is it just glassed in? I can't see any fittings. how does one replace it or rebed it with confidence? i have read that the balsa core is largely on the port side in support of the engine mount. does that mean there is no balsa on the starboard side with the chain plate?

all help appreciated,

kuriti

Okay, i drilled a test hole in the middle away from all other holes, damp wood. Having read a bunch of posts on other forums, i know my fate is sealed. So i am changing my request to, what did you learn when recoring your transom? Any tips or tricks? What replacement wood/material do you recommend? Looking at it again, it seems to be only be the 3/4 on the port side with a core. Mine is a MK2 with a lazzarette.

My question on the chainplate stands.

Chainplate is just glassed in... on starboard side. yes only the port/engine mount side has a core.

Conventional wisdom says to save your "external skin" and do this job from the inside... but I think it should be done on a case by case basis.

Doing it from the inside does save you less "layup" work, but it also means you're working in a really cramped, tiny little spot with fiber shavings going everywhere, breathing them in, sanding the external glass smooth, mixing epoxy, or trying to crawl into the QB pre mixed.

I did mine from the outside for a few reasons. My boat had at least 2-3 different mounts on it over the years, which I don't think were every truly sealed correctly so my balsa was so wet and rotted that baby food would have been firmer. In Mizu's case from all those different mounts the external glass had also been flexed over and over and over again, and had some really deep cracks in it. After cutting the external skin out, and inspecting these cracks, there was probably only 2-3 layers of glass + gel coat actually intact on the stern.

In the end I still had to cut a bit of the internal skin out and crawl inside the qb's to put a couple layers on. It sucked, it was terrible, horrible, and completely wretched. I really can't imagine doing this job from the inside, it was THAT terrible. And all I was doing was sanding/grinding the inside to get the area clean enough for my inner skins to stick to.

It took A LOT of fiber and resin to do it from the outside, but I think I made the right choice. And when talking to another owner in Fleet 1 that did it from the inside, he concurred.

Later
Christian

I couldn't wait and already started the demo from inside. Good news though. I cut and chiseled out a 6x6in section including where the bottom 4 bolts hold the gudgeon. The bottom inch around the bolts was wet, but above that i was taking chunks of external epoxy with core. So it wasn't delaminated and still strong. I am almost positive this boat has always been a trailer queen, and it looks like most of the intrusion was limited to near the holes. I plan on using the flexible dremel attachment and a roto zip bit to cut out an inch or so around each hole, then refilling with colloidal epoxy. I am almost positive that if i cut and chiseled out the whole thing it would be less strong.

Thanks for the reply cklamp, i think you are right about the case by case basis. My lesson learned is to do smaller exploratory cuts in the future.

I am following up this post for the benefit of others. Don't delude yourself that your transom is "just a little wet". I had hoped mine was just in spots, but it turned out it needed the whole treatment. I have about 80% cut out, but have moved to another project for the time being as my dremel died. Using a dremel with an flexible extension and cutting wheel made this easier than I expected, but still no field day. Much of the core was mush, just replace it.

any suggestions on alternatives to wood for replacement? what kind of foam core could be used and where have you gotten it. needs to be not more than 2-3x's as expensive as wood to be practical as i can just isolate each bolt hole with epoxy if i use wood.

thanks!

Personally, I just used a balsa core for mine again... I figure if it lasted 30 or so years without the "epoxy plug" where the bolts go and all the obvious and serious abuse 897 endured, then it should last at least that long with proper sealing and caring on my part as well.

Jim Altice used some sort of synthetic core in his Deck when he recored Parveen... You could check with him on what it was called, I can't recall off the top of my head.

Later
C

I was looking at this Coosa board the other day. It might suit your needs.
http://www.boatoutfitters.com/Coosa-Board

I don't know if coosa can be formed like the end grain balsa panels can be or not? The transom on the SJ21 has a small bit of curve to deal with. That being said, coosa is pretty awesome, and some RV shops are even making campers out of the stuff instead of the traditional Pine or Aluminum.

later
C

Well, i finally finished my transom rebuild. It wasn't as difficult as i expected, well maybe 3/4 as difficult. I plan on doing a write up on it later since i haven't seen one to date. I have also dropped the keel, sanded off the non-skid and fill/faired every little scratch on the topsides. I plan on finishing the bottom prep this weekend and begin painting shortly thereafter. Should look like a new boat when I'm done!