Keel Doctor - and fiberglass patch questions

sal's dad · Post by **sal's dad** » Fri Mar 28, 2008 10:33 am

I am finally working on the Corinthian - the first task is to get the hull sound. Three things jumped out as needing some glass/epoxy work:

- Installing a garboard plug (there was none before, and the boat had sat on the hard, full of water, for an indeterminate number of years - I had the yard drill a 1" hole after the first day I saw it)
- Removal of the head, and sealing the thru-hulls. (Anybody need a vintage head? - a real collector's item!)

- Investigation of a crack in the ballast area, which was weeping moisture even after the bilge was drained to about 2".

This last item turns out to be a problem. I cut away the bottom paint and gel coat (using the nifty Ryobi 18V planer - minimal dust!) and found that there is a void around the lead, maybe 1/2 wide at this point, with a significant amount of un-resined fiber inside. Presumably this void has been full of water for 20 or 30 or 40 years.

Anybody encountered this? Any suggestions? I am thinking about a second garboard drain, or an inside drain from the ballast to the bilge, or simply filling the void with something - epoxy? concrete?

Thanks a million!

jhenson · Post by **jhenson** » Fri Mar 28, 2008 1:48 pm

I’m not that qualified to judge the best method of repair here, but you might consider two-part foam for this problem. You might be able to pour it into the void with a section of narrow PVC pipe, conduit, or similar tubing. The foam should expand to fill the entire void and then exit the existing hole. Once cured, you can then shape the foam to provide a mold for laying up material for the repair. Some form of relief hole may be necessary to allow the excess foam to escape, say on the other side of the keel. A little of this stuff goes a long way.

Joe

sal's dad · Post by **sal's dad** » Sat Mar 29, 2008 8:15 am

A bit of googling brings up :

Good Old Boat article on the Ensign - one piece of advice is to drill a small drain every fall, and fill it before launch! (just don't forget!)
http://www.fios.org/roseman/pyc/ensign/ ... ission.pdf

http://www.pearsonariel.org/discussion/ ... 604&page=3

bcooke · Post by **bcooke** » Sat Mar 29, 2008 11:23 am

They make re-usable drain fittings too.

This one is from the Hamilton Marine online catalogue.

-Britton

Rachel · Post by **Rachel** » Sat Mar 29, 2008 4:20 pm

Speaking of garboard drains, I had an interesting experience with one of the Buck Algonquin drains we're fond of* when a co-worker was installing one the other day.

I happened to be walking by just as he was tightening the fasteners, and he said "Hey, take a look at this - there's a drop of "goodge" there where I'm pretty sure there wasn't one a moment ago." He wiped it off and although no more appeared we decided better safe than sorry and he removed it before the 5200 set up.

After he cleaned it up, sure enough, there was a tiny hole that you could see on the "back" side (that goes up against the boat) just where the bulge of the keyway groove, the threaded part, and the back of the flange meet. It looked like a flaw (pit) that came about when it was being cast, not a crack or other problem. It probably would not have sunk the boat, since it was a little ways "in" from the outside, but still certainly undesirable! We sent it back for a replacement.

I have another one of these sitting around waiting for me to drill a hole in my own boat, so I'll have to take a close look at it in that area, although my guess is that it was a fluke on just that one, and it's still my favorite garboard drain (I guess it's weird to have a favorite garboard drain, isn't it...)

Rachel

*(Not the one Britton posted a photo of, but a different one also available at Hamilton Marine that is ALL bronze. Many of the "bronze" ones these days, if you read the fine print, have a brass plug. Ugh.) Here's the one I'm talking about:

http://store.hamiltonmarine.com/browse.cfm/4,2236.html

Note that they also sell spare plugs for this model.

Ancient Race · Post by **Ancient Race** » Sat Mar 29, 2008 8:05 pm

Rachel wrote:Speaking of garboard drains, I had an interesting experience with one of the Buck Algonquin drains we're fond of* when a co-worker was installing one the other day.

Ha! Made me look, Rachel.

I have a Perko 124 bronze, also with a brass plug. I was going to install it in the Seafarer next week. So when I read your cautionary tale I was, well, cautioned.

But I see mine isn't it. And in any case fresh water is for bathing.

Greg

Rachel · Post by **Rachel** » Sat Mar 29, 2008 10:37 pm

Looking back at my post, I might not have been clear about one thing: What I was trying to say is that the Buck Algonquin drain plug that I referred to (the one that is shown in my last post with it's own "wrench" IS all bronze - both the flange and the plug. Many others that say they are bronze have a bronze flange but a brass plug, and I prefer all bronze.

Just check for the aforementioned flaw to make sure that was an isolated incident (I'll re-post after I've looked at mine, and I'll also check the new one we get to replace the flawed one).

Rachel · Post by **Rachel** » Tue Apr 01, 2008 12:44 pm

An update on the Buck Algonquin bronze garboard drain:

We received a replacement drain today and there is no sign of a flaw where the previous one had a flaw and a small hole, so it looks as though it was probably a one time bubble or impurity that caused a casting problem.

Rachel

sal's dad · Post by **sal's dad** » Thu Apr 10, 2008 9:17 pm

So I drained the keel "void" as best I could, (drilling a number of 1/4 inch drains along the bottom, and blowing into the void with a hairdrier for a few hours) though the glass fibers are still damp. Then tilted the boat forward, and filled the lower couple inches of the void with epoxy.

Upper left are the head thru-hulls, far right is the new drain, and the blue line a couple inches up is the approximate level of the epoxy.

Closer view of the damaged area, and the drain.

New drain, note cured epoxy, and hole (approx 3/8) thru the lead to the other side of the void. This allowed epoxy to flow thru (pretty sure about that!) and will allow water to drain. The lead ballast is a bit off-center, more than 1/2" from the hull to port, less than 1/4" to starboard. Which would explain why the damage was almost entirely to port.

I have tilted the boat up at the bow, so I can now fill the aft portion of the cavity so it flows to the drain.

A couple questions:

Fiberglass integrity seems good, and all those little holes I drilled have a small drip "nipple" of hard epoxy protruding. The shoe is now about 2" of solid epoxy, bonded to the lead, inside the original glass. Can I just sand the nipples off. skim with epoxy and paint? Or do I need to glass over? I would rather glass only the sides of the keel, not wrap around.

Patching with glass-epoxy: In critical areas, I have ground down to the underlying fiber. Do I need to uniformly grind off the gelcoat? or can I epoxy right over it? For example, in the next picture:

The lower hole, I counter-sunk a bit for the drain flange, put on a light coating of epoxy, and now will bed with 5200 or 4200, then epoxy on a bit of fairing around the protruding flange.

But the upper hole I will patch - fill the hole roughly, grind smooth, then patch with glass. But can I just glass over the gelcoat? or grind at least part of it down to fiber? (I think I know the answer )-:

Thanks!

sal's dad · Post by **sal's dad** » Thu Apr 10, 2008 9:23 pm

very cool - the original poster can change the thread title, by editing the first post!

Post by **Tim** » Fri Apr 11, 2008 6:17 am

When patching, you're better off to grind away the gelcoat and adhere your new laminate directly to the old.

In addition, grind yourself a shallow (roughly equivalent to the thickness of the new material you plan to add) divot and taper around the area to be patched so that your new material ends up essentially flush with, not proud of, the surface.

sal's dad · Post by **sal's dad** » Fri Apr 11, 2008 6:34 am

Yup, I figured...

In the damaged area, the glass was surprisingly thin, so the patch will be a bit higher. Also, I have to build up maybe 1/4" to fair the keel drain; again glass is too thin to countersink it there.

And what do you think of leaving the 1/4" holes simply plugged with epoxy, no glass over?

Hirilondë · Post by **Hirilondë** » Fri Apr 11, 2008 6:43 am

sal's dad wrote:Also, I have to build up maybe 1/4" to fair the keel drain; again glass is too thin to countersink it there.

You don't have to, not that you can't or shouldn't.

Post by **Tim** » Fri Apr 11, 2008 8:11 am

You don't need to countersink the drain flange (you can, if you choose). Frankly, I think it's a waste of time and materials on the typical non-racing boat that has plenty of other irregularities in the bottom. That slight protrusion makes an insignificant difference to your boat's performance, so unless you have your own reasons for wanting to do so, be assured that it's not a requirement.