Keel design question

[MB750]

Being the ever vigilant researcher of potential sailboats to purchase and learn on I'm wondering something about keel design.



Everybody knows about the Catalina smile. If I have my facts straight it appears to me that it's an affliction on the Catalina 27 and 30 where the keel literally starts separating from the hull due to Catalina's design of putting plywood within the keel stub along with epoxy and fiberglass that eventually falls apart from moisture intrusion. This disintegration of support material actually lets the keel slowly drop and in conjunction with keel bolt corrosion could cause loss of the keel entirely.



Now the questions:


Why do you only hear about this on Catalina boats?

Are any other manufacturers afflicted with this as commonly as Catalina?

Are encapsulated keels something I should pay closer attention towards if I'm planning on purchasing a more long term cruiser?



I've also read about the fix too: Essentially remove the keel, remove all the crap plywood, build up a layer of fiberglass/epoxy only and reinstall keel with about a gallon of 5200.



Last question: Are all sailboats with non-encapsulated keels mounted like this? I have trouble believing a few layers of fiberglass and epoxy can support a hanging ton (or two) of lead with a few 3/4" bolts but maybe I underestimate the strength of fiberglass.



Thanks for listening, any info is appreciated.

Matt

[GordMay]

Catalina has no special claim to keel smile. Well, maybe some claim because the company unwisely used plywood in its keel stubs up until around 1987 or 1988, which has tended to make the “Catalina smile” somewhat broader than some others.
Pretty much any older boat, with an external/bolted keel, will eventually develop a keel smile.
Ie: C&C ➥ http://www.cncphotoalbum.com/doityou...mile/index.htm
Plastic boats flex; metal keels don’t.
The thousands of fatigue cycles, induced while sailing, allows a slight movement at the hull-to-keel joint, eventually exceeding the limitations of typical marine caulks and fairing putties, causing the crack to form.

Rust stains on a lead keel are a sign of corroding bolts, not just the flex smile.

If it’s just a simple smile (no structural damage), the smile repair should be done with a structural, yet flexible, epoxy (ie: G/flex 655 or other).

[Lnewman]

Catalina is definitely known for the smile, as lots of the older boats had them. I had a 70's vintage Catalina 27 many years ago that developed the smile, which was repaired best as could be.

You need to narrow your boat choices, then focus on how they were built. Try to find out if there is any design flaw in where the keel attaches. The internet definitely makes it much easier to find out stuff, if you can weed through the garbage data.

Practical Sailor had a good article on keels and their maintenance needs. Lead keels require less maintenance and are a little more forgiving when you strike something. Iron keels a bit more maintenance as they can rust if their epoxy coating gets compromised and not so forgiving when you hit something. Encapsulated keels can be a pita if the fiberglass encapsulating the ballast gets compromised (by say a grounding damage). With any boat you do some research and then have a very good survey performed, and cross your fingers you chose wisely.

Every boat is a compromise. You make your short list of desires, then try to tick off as many as possible. My short list is traditional design, sea kindly, relatively fast, sound construction, no cored hull (deck of course is cored), lead keel. Doesn't need to be an apartment down below.

[thomm225]

The nice thing about encapsulated keels especially on the older full keel designs is that they can handle quite a bit of abuse such as hard groundings, etc

The keel on an old Bristol 27 as an example is a total beast

[Cheechako]

The smile has nothing to do with plywood etc. It's just flex of the hull fore and aft of the keel attachment creating a smile shaped crack, often just a surface crack. Think of it this way: if the keel hits a rock hard, the weight of the boat tries to carry forward. This flexes the hull up behind the keel and down in front of the keel creating a smile shaped stress point. I have seen a charter boat that hit a rock quite hard and the hull flexed like this detaching the engine bed aft of the keel!

[Lnewman]

Good articles on keels....

https://www.practical-sailor.com/blo...s-11030-1.html

https://www.practical-sailor.com/blo...s-12421-1.html

https://www.practical-sailor.com/blo...s-11428-1.html

https://www.practical-sailor.com/iss...y_12004-1.html

And some notes from Sailnet community....

Part of the "Catalina" reference is because Catalina sailboats of a certain vintage suffered especially severe separation. The reason for this was that they encapsulated a wood block into the keel stub. Over time, as stresses caused the keel bolts to wiggle a bit, and the polyester resin to crack slightly, water ultimately intruded into the wood, leading to rot. As the wood spacer rotted, the keel would sink a bit, leading to separation between the keel and the keel stub.

Catalina ultimately abandoned the use of wood spacers in the keel stub, and many owners of the older boats have removed the wood and filled the space in with epoxy.

I do not know exactly what model years were affected. I know that my boat was built well after Catalina abandoned use of wood in the keel stub. You'll have to do some research to find what years had the wood in the keel stub.

[Orion Jim]

The Catalina 34 has the same construction and suffers the same fate.

[Don C L]

No, not everyone connected keels to hulls the way Catalina did. As an example, recently I saw a Yankee 28 on the hard and I was impressed by the keel/hull connection. While there will probably be a line visible on almost all boats' keel/hull joint, a boat like the Yankee will not suffer a smile due to the notched keel and stub, so that the stub helps support the keel. Can't find any shots of it right now.
I like my encapsulated lead ballast, like thomm's up there... stout and one less thing to think about, and my long keel slides over everything and I have no qualms about any damage in a grounding... though I'm not planning to test it!

[MB750]

Great info all around, thanks fellas. Gives me a lot more to think about.



My primary consideration right now is how long I plan on keeping my first boat. Since it's a learner, I'm less inclined to buy something that's top notch on the used market even though it's smaller than I'd need for a longer, seasonal cruise to a destination. That being said, if the keel has a smile, I'm less inclined to care since I probably got it cheap anyway and it'll be a burner to me as far as retention is concerned.

[thomm225]

Originally Posted by MB750

Great info all around, thanks fellas. Gives me a lot more to think about.

My primary consideration right now is how long I plan on keeping my first boat. Since it's a learner, I'm less inclined to buy something that's top notch on the used market even though it's smaller than I'd need for a longer, seasonal cruise to a destination. That being said, if the keel has a smile, I'm less inclined to care since I probably got it cheap anyway and it'll be a burner to me as far as retention is concerned.

This was sort of my plan but after buying a Bristol 27 for $2,000 and adding things here and there, I found I have a pretty good cruising boat already and found no need to replace it with a larger newer model. Attached pictures are from 2011 and 2019.

The Bristol 27 has a capsize screening formula of 1.71 which is quite good.

https://sailboatdata.com/sailboat/bristol-27

Point is you can buy a cheap/low priced boat without a keel smile that can also be used to cruise

Many of the boats on this list have encapsulated keels also.

https://atomvoyages.com/planning/goo...oats-list.html

[Ericson38]

Originally Posted by Cheechako

The smile has nothing to do with plywood etc. It's just flex of the hull fore and aft of the keel attachment creating a smile shaped crack, often just a surface crack. Think of it this way: if the keel hits a rock hard, the weight of the boat tries to carry forward. This flexes the hull up behind the keel and down in front of the keel creating a smile shaped stress point. I have seen a charter boat that hit a rock quite hard and the hull flexed like this detaching the engine bed aft of the keel!

Yes, plywood. Our friends bought a new 1990 Catalina 36 in Long Beach. We had a 1982 Ericson 38 at the time. So they had a wet bilge after about a week, which their prior Catalina 30 didn't have. He checked the tightness of the keel bolts and got a large snap sound, which was a long crack lengthwise in the keel stub that ran about 3 feet. Catalina later dropped the keel and dug out all the plywood and replaced with solid glass and resin.

[Cheechako]

Originally Posted by Ericson38

Yes, plywood. Our friends bought a new 1990 Catalina 36 in Long Beach. We had a 1982 Ericson 38 at the time. So they had a wet bilge after about a week, which their prior Catalina 30 didn't have. He checked the tightness of the keel bolts and got a large snap sound, which was a long crack lengthwise in the keel stub that ran about 3 feet. Catalina later dropped the keel and dug out all the plywood and replaced with solid glass and resin.

Yeah, but that's not the infamous "smile" !

[wingssail]

Originally Posted by GordMay

...Pretty much any older boat, with an external/bolted keel, will eventually develop a keel smile...

Well, not all.

Our late 70's IOR race boat, fairly light for a 43' boat (16,000) with 6500lbs of external lead keel bolted on with twelve 1" bolts and 8"x8" 1/2" thick steel backing plates in the bilge has not developed a "smile".

This boat has had hard usage.

In the early years we could see some cracking of the paint and filler at the leading and trailing edge of the hull/keel joint each year when we hauled. We filled them with bondo. But for the last ten or twelve years, no cracks!

Three events worth noting:

1. One grounding at 7+kts on a reef (which we knew was there). This took about a pound of lead out of the front bottom of the keel, which I replaced at the next haulout with melted lead and a jury rigged mold (and some lag bolts partially screwed into the keel to help adhesion). There was no hull damage or leaking from the grounding.

2. In Australia in 2002 we had the keel dropped off to inspect the bolts (they were fine). Of course this was a opportunity to snug everything up and a new pile of sealant.

3. In 2011, in Africa, we replaced two of the keel plates. They were rusting badly. We now need two more to be done. They are on the list.

So, if a old throwaway IOR race boat built in a barn by rednecks can avoid the smile, there is hope for other boats.