Keel Damage

[larrysimonis]

Project update: This CP16 was the subject of an earlier post (search "keel cracks" by Schwartz16 July 02, 2010) and my eventual purchase last April. Finally got the keel opened up today by cutting out a piece the size and shape of a football on the port side forward. It cut like butter with a Dremel cutting wheel, and the piece just fell out. PO had ground it down very thin and then built it up with a thick patch of Marine-Tex. The Marine -Tex has either become waterlogged or the hardener ratio was wrong, because it is very soft. The concrete is surprisingly solid, but the scrap iron tht Hutchins threw in has corroded away fot the most part. This has caused voids in the concrete that will be natural water collection points. I'll have to do the same thing to the starboard side, the leave it alone to dry for the next month or so, The other side is actually worse. Any suggestions on filling the rust voids?

[Bob23]

I have no experience in this but I'd use epoxy, maybe mixed with lead shot.
Bob23

[Allure2sail]

Hi Larrysimonis:
I'm rather surprised that it was scrap iron that you found mixed in with the cement. I was always under the impression that they used cement and lead ingots to achieve the weight of the intended ballast. Has anyone else out there that did a keel repair on a ComPac of any size found this as well? How many rust out voids can you see in the areas that you have cut open? As far as the keel encapsulation repair, I agree with the resin suggestion, although it's a little tough to work with on a vertical surface. Perhaps you could use a thin piece of plywood generously coated with mold release and propped up against the keel  to hold the resin in place until it set. I think I would also look into also using some fiberglass mat or the micro balloons that is used with the West System made for repairs of that type. As far as Marine-Tex, I haven't had much luck with it either. As far as the exposed voids from the rusted out scrap iron, the resin will just fill up the ones exposed by the fiberglass you cut away. The ones you can't see will just stay as voids. Wish I could be of more help, but I just never got into that type of repair.
Good luck
Bruce
S/V Allure
Swansea, MA

[Shawn]

I don't know how big your voids are but check out this site for one guys way of replacing/repairing ballast with lead shot and epoxy. Might give some ideas.

http://havasumontgomerys.piczo.com/?g=23004804&cr=1

Shawn

[larrysimonis]

Thanks for the link on ballast replacement.  The steel looks like random bits and pieces that would be swept up in any manufacturing facility, and the concrete has some serious gravel in it. The gravel bridged a lot of the metal pieces, so that caused more small voids. The plan taking shape is to cut out 2 or 3 panels on each side to expose as much of this mess to air as possible. While that is drying, I can remove the poorly cured Marine-Tex from the rest of it with a rotary wire brush. Since the ballast will never be truly solid and always prone to retaining water, we'll just have to make sure that water never again gets in there by totally ecapsulating the ballast on top. The local building supply store has a section of concrete patching products, one of which is an epoxy. If anyone has any experience with this stuff, or any other thoughts on The Plan, feel free to chime in.

[larrysimonis]

This CP16 (Hull#59, built 06/75) has a bunch of the little triangular bits that are left over from punching 2" discs out of 1/8" sheet steel, most of which seem to be kind of nested low forward in the keel. I'll try and post pics when my wife gets back from Oregon with the camera, and I figure out out how to do it. I suspect it was an attempt to improve trim by getting as much weight forward as possible. Since overkill is always an option, it could be chiseled out and replaced with 1lb lead ingots, of which I have about 500.

[skip1930]

Forget the rust. Forget the crummy cement. Weight is weight. Encapsulate all of the mess within a water tight keel. To harden the Marine-Tex because the ratio was wrong, or not mixed up enough or??? whatever try heating the Marine-Tex with a hair dryer or paint stripping gun to 'kick it over'.

I added a 'Keel Boot' to the bottom of my CP-19, glued on with Marine-Tax three or four seasons ago. Now I can drive over the rocks without scratching my fiberglass keel bottom. Search the site under 'Keel Boot'.

skip.

[larrysimonis]

Point taken.  Marine-Tex of better quality was applied directly to the concrete to cover a 4"X6" hole on the starboard side where damaged fiberglass was cut out, so that will stay. The rest of this stuff covers the forward  quarter of the keel like plaster. I'm removing that to get at the cracks so they can be beveled for a proper repair. About halfway now, so should have it in a day or two. Had similar issues with a shoal-keel Guppy13 this winter, except that one had 50# of iron punchings mixed with (wet) sand in the bottom of the keel, and a 6" or so concrete cap over that.  Replaced the sand and iron with 125# of lead ingots inserted through the holes where we cut the bad FG out, then glassed the holes.  To finish it off, we drilled another hole right at the bottom of the concrete cap, inserted a tube, and poured resin in to encapsulate the whole thing. I'm leaning toward injecting some type of hi-tech goo into the voids around the steel ballast to reduce the volume of water that could ever collect there, plus cut off the oxygen supply. It may not be perfect, but it has lasted for 36 years so I'm inclined to cut Hutchins some slack.

[skip1930]

You want the 'cap' to be water tight. Otherwise the water entering the keel and not stopping at the cap will flow into the boat...glug, glug, glug, wheres those life jackets?

skip.

[Allure2sail]

In agreement with Skip1930........
If the keel has not been sealed off from the bilge and you hit a submerged object (rock, log, mooring) and break through the encapsulation of the keel It's time to START BAILING !!!!!!!  I think capping it off with some type of resin that will bond to the cement or as you call it a hi-tech goo is a good idea, call it extra insurance. Best of luck, please let us know what route you took and how it turned out.

[skip1930]

TRUTH be known a McGregor 26 with it's self filling water ballast tanks and rudder can be easily sunk by simply drilling a 1/4" dia hole at the top-o-ballast tank to let the trapped air out and the ballast water into the hull's interior. Same as an unsealed keel cap.

skip.