Reinforce a fin keel

[Hermit Scott]

When I hauled mt C30, it had a 1" crack in the front and a 1" crack in the back of the keel right at the joint. It could have been from me running aground on a sandbar while going to the yard, I don't know.
I bottom painted it 4 months or so ago. I widened the little cracks back into the keel until it wasn't cracked, and all I saw was clean uncracked fiberglass. I filled it with 5200 and painted over it. Now that I have messed around with fiberglass a bit, I am thinking of grinding out a 5" wide or wider band around the keel with the keel joint at the center and filling it back in with fiberglass and epoxy. I want to extend and thicken the area around the keel joint.
Is this an OK thing to do? Do I need to retorque the keel bolts at some point? How thick should I go to have a strong joint?

 

[Steve Dion]

HS: You need to check out the Catalina sight regarding this issue too. I think there is a feature on "some" Catalinas called the "Catalina Smile"

I would suggest that you have this professionally inspected. The entire keel stub should be inspected and "if" it is okay, you need to fix it properly.

If you loose a keel offshore it could be "The End".

 

[Hermit Scott]

I drilled one hole into the plywood keel stub to see if there was any obvious rot. It looked clean. There are no cracks around the keel bolts, and they look good as much as can be seen looking in the bilge. I have looked at the keel joint at various places around the keel by grinding away down to the sealant. Everything appears to be good. I am going to get a plug bit and drill out about 10 places in the bilge to see if the keel stub is dry.
I am farmiliar with the catalina smile. Alot of the advice I have heard is "fill it with 5200 and go sailing". I am not really worried about losing this keel, I am worried about keeping the keel stub dry and reinforcing the keel joint to prevent any more smiles that aren't on my face.
Unfortunately I am going to be the only one inspecting and improving/repairing my boat.

 

[jibes138]

Losing a keel

I've heard of keels falling off at seea but this is usually large racing boats built on the edge of safety, research Drum for instance. I have never seen or heard of a production boat losing a keel. I have seen them leak and have cracks like Scott but never heard of one falling off. Does anyone actually have an example they can relate>
Also most people I;ve seen witht the Catalina smile or the C&C smile just scrape out the joint and put in some more compound and fare it. If you have structural damage from a hard grounding you have another story, this is usually a cracked hull aft of the keel that typically runs like a semicircle from port to starboard. This should be professionally repaired if the boat is worth it. I doubt a grounding on sand will do this. i had a neighbor that was renting his C&C 34 out to sailors who ran it onto the rocks at the watch hill passage. His boat had this structural failure and it was a pretty significant repair. He stopped renting out his boat after that.

 

[sailaway78]

If you add glass

Hermit,
If you add glass to the hull to keel joint, be sure to torque up the keel bolts first. You have probably already thought of this, but if you glass it, and then pull up on the keel, may overstress you glass work.

 

[Ross]

Hermit some of the unidirectional glass fabrics are rated as having a tensile strength of 600 pounds per linear inch When you apply that to booth sides of the keel you get about 14000 pounds per foot. So I think that you primary concern will be spreading the load as widely as you reasonably can. Several plies, well bonded to the keel and to the hull will make the keel and hull intregral. Once the bolts are properly torqued and the glass has cured it should be one more thing that you don't need to woory about.

 

[Hermit Scott]

Unidirectional? Is roving unidirectional? I saw on ebay when I was buying some glass cloth they has some biaxial. None were listed as unidirectional though. What specific name or type do I need to get?

 

[Ross]

Consider a fabric woven with 24 ounce roving in one direction and 10 ounce strand in the other direction. If you are reinforcing the keel, the weave strand that runs parallel to the crack provides no strength. Therefore you would seek a fabric that placed 90 per cent of the strength of the weave across the crack. That is the purpose of unidirectional fabric. http://thayercraft.com/index.htm

 

[Hermit Scott]

Great description. I will try to get the right weave for the job at hand.

 

[Ross]

There is a very good chance of getting an "engineering sample" if you ask politely. I have done that with fabric and with epoxy.

 

[Stu Jackson]

Hermit, please do a search on

"THE CATALINA SMILE"

You can even cut & paste the quotation marks!

Lotsa prior input.

It's a "standard" on this board and about every other one about these "cracks".

You did the right thing.