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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

calling all KEEL DOCTORS

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DrScow
Deckhand

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USA
9 Posts

Initially Posted - 03/24/2008 : 20:45:53

good folks;
hello from the gulf of maine, south portland.
i purchased a 1978 catalina 25 fixed keel last year with the knowledge i had to make some keel repairs this spring. the previous ownwer was vague about the keel cracks; there does not appear to be any significant keel shift or keel bolt issue post "bump of the keel". i believe the keel to be iron based on the exposed rust. i had planned to grind off any loose material, inject 5200 in some of the smallest cracks, fill in with a "marine epoxy or filler"; prime the keel and bottom paint. i would greatly appreciate input as to plan and materials [brands] and what at all costs not to do.
thanks; kaptain pete f.
purpooduck sailing klub [psk]

Hard Starboard

Edited by - on

ClamBeach
Master Marine Consultant

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3072 Posts

Response Posted - 03/25/2008 : 08:44:37

Hmm... tripod doesn't like linking?

Edited by - on

JohnP
Master Marine Consultant

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1520 Posts

Response Posted - 03/25/2008 : 10:18:24

Pete,
Here are your pictures linked to Shutterfly. You might want to use their site, if Tripod isn't working right.

That's some damage! What to do?

I would probe the holes and cracks to remove loose pieces and then remove all paint and sand/grind (with respirator) the existing surface making a 1-2 ft margin around the damage to put layers of fiberglass over the area, then a barrier coat of epoxy or gelcoat, then paint.

But maybe others might know if fiberglass in that spot would be strong enough.

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 03/25/2008 : 11:41:35

Ouch! It's hard to tell on that first pic, but it looks like a substantial chunk was lost forward of that crack--the bottom should be almost perfectly flat with sharp edges from the forward to the aft edge. And it looks like you're about to lose some more. Fiberglass and epoxy are problematic for holding together cast iron that's that far gone--the inevitable rusting will likely cause the resin to let go. You can try a fiberglass "diaper" around the bottom, and then grind, prime and epoxy the rest of the keel... It won't be pretty, but it'll sail to windward. Or you can soak that crack with rest reformer and then fill it with Marine Tex and hope for a few more years before the piece falls off. Even if it does, there's still a lot of cast iron down there.

Edited by - Dave Bristle on 03/25/2008 11:44:48

JohnP
Master Marine Consultant

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1520 Posts

Response Posted - 03/25/2008 : 11:49:15

You have nice rocky shores up there in Maine. How often will you be testing the repair by skimming rocks and running aground with a jolt? Even a solid fiberglass patch is not as hard as iron or granite.

Edited by - on

Steve Milby
Past Commodore

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USA
5902 Posts

Response Posted - 03/25/2008 : 12:05:39

I had a recurring problem of that sort with my cast iron keel for about 20 years, and think I finally solved the riddle just before I sold the boat. First, clean all the big chunks of rust off the keel with a hammer and chisel, as well as any old, loose fiberglass filler. If you tap all over the surface of the keel with the hammer, you can hear the bad spots. The bad fiberglass filler will sound dull. The solid cast iron will have a ringing sound, and the good filler will also ring. Remove all the dull sounding filler. Then sand the surface to remove as much loose stuff as possible. Then use a wire brush fitting in your electric drill to remove the rust in all the little depressions. I spray 2-3 coats of rust reformer on the bare surface, just to prevent it from starting to oxidize until I can do the next step. Then, apply 2-3 coats of coal tar epoxy (VC Tar) over the bare surfaces. Then apply a good underwater filler to smooth over all the depressions and re-shape the keel. Grind and /or sand it smooth, and coat it with antifouling. Finally, the step that I believe ultimately stopped the recurrence of the problem. Attach a zinc anode to the keel. My keel repeatedly developed bubbles under the filling, and I believe a chemical reaction was causing it to happen. The gas that was produced would create a big bubble under the filling, loosening it's grip on the keel. After I attached a zinc anode, I never had the problem again.

Edited by - on

Dave5041
Former Mainsheet Editor

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USA
3758 Posts

Response Posted - 03/25/2008 : 13:06:04

All iron keels need zincs and regular inspection. Use non-colloidal filler like chopped glass or glass micro spheres, not silica and barrier coat at least as many coats as the manufacturer recommends. Glass cloth will never be a long term solution unless the entire keel is encapsulated, and even then it is marginal. Differing expansion/contraction eventually breaks the epoxy/metal bond and allows water to be trapped causing rust, blistering, and separation. Iron keels are fine (the European Union banned lead keels for builders due to toxicity during construction and leaching into the water), but annual inspection is required.

Edited by - on

bigelowp
Master Marine Consultant

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USA
1776 Posts

Response Posted - 03/25/2008 : 22:24:59

Pete: Must say that your keel looks like a big project. You might check to see if anyone is parting out a FK to see if you can get a better keel.

Steve: where did/would you attache the zink on a C-25? I know the outboard needs one but where on the hull should it be attached and/or what size would you recomend.

John: Why are some of us just plain old analog guys in this digital world. darned if I can get pix on here no matter how simple I am told it is . . . can't be my age, can it?

Edited by - on

Steve Milby
Past Commodore

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USA
5902 Posts

Response Posted - 03/26/2008 : 06:46:39

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Steve: where did/would you attache the zink on a C-25? I know the outboard needs one but where on the hull should it be attached and/or what size would you recomend.<hr height="1" noshade id="quote"></blockquote id="quote">It should be attached to the keel itself. It's size shouldn't be a critical issue. Ordinarily, it should last a long time. Select one that won't create a lot of drag, or interfere with the smooth flow of water past the keel. I drilled two mounting holes in the iron keel, and then threaded them with a die. The mounting screws have to connect the metal of the keel with the metal of the zinc. Also, when you paint the bottom, don't paint the zinc.

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Must say that your keel looks like a big project. You might check to see if anyone is parting out a FK to see if you can get a better keel.
<hr height="1" noshade id="quote"></blockquote id="quote">Repairing the keel takes a little time, but it isn't all that bad. I've done it in a day. Perfect is always nice, but it doesn't have to be perfect. No matter how good a job you do, it won't last forever. Either water will penetrate it eventually and cause damage, or you'll hit a submerged rock and knock off a chunk of fiberglass filler and have to repair it. As Rosanna Rosanadanna said, "It's always somethin!" The good thing is that you're working on a big chunk of cast iron, and there isn't much you can do to hurt it, so you don't have to be gentle with it. Fiberglass filler is fairly easy to work with, so, once you learn how to work with it, it'll go much more quickly.

One suggestion that will help is, get a 4 1/2" grinder to shape it. I've tried all kinds of sanders, and none of them will remove excess filler material very quickly. A 4 1/2" grinder will take it off as fast as you can put it on. Then you can do the final smoothing with a sander.

Edited by - on

JohnP
Master Marine Consultant

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1520 Posts

Response Posted - 03/26/2008 : 07:47:57

Buy a good respirator!!!
Buy a good respirator!!!
Buy a good respirator!!!

Oh, did I say you have to buy a good respirator?

Edited by - on

DrScow
Deckhand

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USA
9 Posts

Response Posted - 06/09/2008 : 22:52:34

Greetings from South Portland ME;
Many thanks for all the replies from the membership.
It is so great to have a resource like this for a first time Catalina owner like me.

Just back from the boat yard 23:27 EDT. I have knocked into the keel gaps to find what appears to be marine cement inside a steel / cast iron shell. Pics to be posted Tuesday [worth a million words]. I feel like a dentist who went in for a cavity and drilled enough way for a dental bridge. In the first posted pic, the line in the keel [frown] was knocked off with a tire iron to expose what appears to be cement? I lost about 15 pounds [worth 200 pounds of righting lever??].

The question is: Was the 1978 Catalina 25 fixed keel cement filled steel shell?? I thought the keel was solid cast iron? Did I run into an owner fix / patch job?

My forward plan to get the boat into the water before Halloween is to knock away loose material and coat area with Tiger Hair bondo product. I do not need a 12 meter fin keel to a thousandths of an inch but rather a patch to stand off salt water penetration.

Please advise any Keel Doctors;
thanks;
pete f.

Edited by - on

Steve Milby
Past Commodore

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USA
5902 Posts

Response Posted - 06/10/2008 : 09:31:42

The material you're seeing probably isn't cement. It's probably Bondo, or some other fiberglass filler. The 1978 fixed keel is definitely a solid chunk of cast iron. It's a fairly crude casting, and the factory apparently seals it with coal tar epoxy, and then fairs it with a fiberglass filler of some kind.

I'd suggest you knock off all the old, loose filler material with a hammer and chisel. (Don't try to take it all off. Just remove what's loose.) Clean the cast iron thoroughly with a wire brush bit in your drill. Coat it with a couple of coats of VC Tar. Then fair it with Interlux Watertite Epoxy Filler. Do not use Bondo. The Interlux filler is very good, and it's very easy to work with, compared to other similar products.

After the keel starts to deteriorate as yours has, you'll probably have chunks occasionally pop out, and have to repeat the repairs, but it shouldn't be as extensive or as difficult as the first time. I repaired mine many times, and don't think of it as a big job anymore. Others might see it differently. After you've done it a time or two, you'll learn how to get it done quickly without wasting time and effort.

Edited by - on

DrScow
Deckhand

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USA
9 Posts

Response Posted - 06/13/2008 : 05:13:02

Thanks for the input to all.
Attached are the latest pics. I am planning to use epoxy / sand patching to smooth out the area and CM-15 epoxy [using an upgraded performance material instead of coal tar epoxy] undercoat with a top coat of pettit unepoxy anti-fouling.
pete f.

Images can also be found on the Klub site: http://drscow.tripod.com/index.html

[These images are Lycos Tripod; I am having constant trouble with these image postings.]

Edited by - DrScow on 06/18/2008 05:34:42

DrScow
Deckhand

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USA
9 Posts

Response Posted - 06/29/2008 : 21:44:33

good folks;
splahsed boat on june 26.
knocked off roughly 20 lbs of keel with hammer & tire iron.
coated remaining with interlux watertite epoxy; CM-15 marine epoxy paint and two coats of pettit hydrocoat.
will see in oct on pull to dry;
thanks everyone;
kapt. pete f.

Edited by - DrScow on 06/29/2008 21:45:25

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