cracks in keel serious?

[i-Zapp]

After cleaning the hull last year for first time (new to me boat) I noticed several cracks in the keel that seem to have been there for a while. I am new to the sailing world and hoping this is not unusual or serious.

Should i be concerned? If only cosmetic, should I use some sort of filler (marine tex?) to fill the cracks before bottom painting?

I happened to notice another boat nearby (J33?) that had similar, which kinda put me at ease. My boat is a 1988 33.5' wing-keeled Hunter.

Thanks in advance for your insights!

[Cheechako]

My guess is that is just where the keel bolts onto the fiberglass keel stub. Clean up the groove and recaulk it, grind flush after it sets up before painting.
The aft end crack has a bit of gap, so maybe test the tightness of the keel bolts/nuts.

[Don C L]

Walk around any boat yard and you’ll see most bolt on keels have cracks. The Catalina “smile” (crack in keel) is pretty famous. Most of the time they are not serious, but you really need to have someone knowledgeable check the integrity and tightness of the keel bolts before filling and painting imo.
Welcome aboard btw!

[Cheechako]

The "Catalina Smile" is a crescent shaped hull crack forward or aft of the keel, from flexing of the hull when the keel hits something. :>)

[YachtBroker]

While Common, don't just grind it down and fill and fair it. The keel bolts need to be checked and torque or you'll be doing it again.

This is a common issue with any bolt on keel, but few people torque the keel bolts.

[roland stockham]

Think about the forces - You have a couple tons of steel about 3ft away held to a joint about 4" wide, that's a leaver with a disadvantage of about 10:1 so your 2ton keel effectively looks like 20tons at the joint. Sobering!

[Steve Bean]

All those stains make me wonder where the rust is coming from. Not from lead, not from fiberglass, not from bottom paint, not from fairing material... I would investigate.

[Suijin]

The cracks themselves are not troublesome, as almost all stubbed-on keels have them at some point. But you should most certainly take a look at the keelboats inside. If they have rust on them and streaks and any sign of them leaking, you're going to want to drop the keel and investigate, if possible. Those bolts will be subject to crevice corrosion where the lack of oxygen can prompt corrosion that eats right into the bolt with very little visual cues of what's going on.

The rust on the exterior doesn't bother me, since there is so much of it. Either the keel is steel or something was applied that rusted.

When repairing the exterior, cleaning out the crack and then filling it with any sort of hard fairing compound is a fool's errand. The crack will reappear in short order and then cause damage to the adjacent fairing. You can see that's what has happened in the past by looking at prior repairs in your photos.

You're better off routing out any fairing compound along the length of the joint and repairing it up to but not over the joint above and below. Fill the joint itself with 5200, fair it out, then bottom paint over it. The 5200 has enough flexibility to not damage the repaired hard fairing abutting it.

[jt11791]

Originally Posted by Steve Bean

All those stains make me wonder where the rust is coming from. Not from lead, not from fiberglass, not from bottom paint, not from fairing material... I would investigate.

It's probably an iron keel.

[Mike Banks]

That looks pretty serious to me. Seeing how thin the keel is at this crack location, I am inclined to think this is a design fault that will be hard to fix properly.

The keel needs to be dropped and the keel bolts overhauled and replaced if necessary.

Thin keels are not the huge advantage one might imagine they are at normal cruising speeds--and the thicker the keel the less likelihood of flexing--which is probably what caused this. Stating the obvious I know--

[lolly08]

I've been here. I was hauled out in Mobile at Turner Marine. While the boat was in the slings, Keith Turner gave my keel a resounding kick. (The Kick Test)The keel was loose and you could see it swing independently of the hull. I ended up in the bilge, rebuilt the stations in the bilge and added new nuts to my bolts. If you want send me a message and I'll send the photos. It was a large project.

[Boatyarddog]

Originally Posted by roland stockham

Think about the forces - You have a couple tons of steel about 3ft away held to a joint about 4" wide, that's a leaver with a disadvantage of about 10:1 so your 2ton keel effectively looks like 20tons at the joint. Sobering!

I guess if your not concerned about the keel falling off and the boat flipping over, ignore the obvious.
It should not be dismissed lightly, just check it out further, have a pro do it or take whatever advise you can accept here.
Your the only one that will be using your boat, I assume.
Cheers
SV Cloudduster

[PapaLulu]

Aside from specific data provided by the manufacturer, is there a range of torque settings that would be reliable? I have a small similar crack in our Dockrell 27 (try finding torque specs in that boat).[ATTACH]167917 I had replaced the keel bolts and nuts when I refit her 5 years ago. Had sandblasted the 3K lb cast iron keel and around 6 layers of epoxy/glass. Leading edge with small crack where we faired her but the rest looks good.

[ramblinrod]

Originally Posted by i-Zapp

After cleaning the hull last year for first time (new to me boat) I noticed several cracks in the keel that seem to have been there for a while. I am new to the sailing world and hoping this is not unusual or serious.

Should i be concerned? If only cosmetic, should I use some sort of filler (marine tex?) to fill the cracks before bottom painting?

I happened to notice another boat nearby (J33?) that had similar, which kinda put me at ease. My boat is a 1988 33.5' wing-keeled Hunter.

Thanks in advance for your insights!

This is quite common for boats of this age with a bolt on keel. (Yours is cast iron BTW.)

Being from NE Ohio I suspect you are on Erie and the boat has always been in fresh water.

So the cracks are due to flexure between the keel and FRP stub.

It is quite likely that the tension on your keel bolts has relaxed.

Remove the nuts one at a time, inspecting the visible threads. If it is in really good shape (after being in fresh bilge water prolly more than the lower portions have been in fresh lake water, crevice corrosion below is unlikely), re-apply the nut, and torque to spec. Goto the next and repeat.

If you are really concerned there may be crevice corrosion, proceed one at a time as above but drill a hole alongside each bolt just touching the threads until you hit cast iron at the bottom (after the nut is removed), and use a boroscope to inspect the exposed threads all the way down. Bright metal where the threads were skinned all the way down is a good sign. If good, rinse holes with acetone and fill with thickened resin. Re-apply nut and torque to specs

If you are really, really concerned about crevice corrosion, build a jig to hold the keel, lower the boat onto it, remove all of the keel bolt nuts, and lift the boat, leaving the keel in the jig (prying and wedging as necessary to get it to release). Best to have new bolts there and ready to put in if your need them, after going to all this trouble.

Wire wheel the bolts in situ and see if there is any bad corrosion. If there is cut them off, drill them out, and tap threads for the new ones.

Clean the mating surfaces, run masking tape 1/4" down on the keel and up on the stub. Squirt in a tube of 3M 5200 on the top of the keel and lower the boat back on the keel. Turn on the nuts and torque to spec. Spread the 5200 thin on the masking tape, and peel the tape while sealant is wet.

If you didn't bother to lower the keel, but did re-torque all nuts, now you need to address the external crack.

Remove all loose and delaminated fill along the crack. Fill fresh and fair.

To prevent further cracking even though the keel bolts are tight, run a V-groove in the fairing compound (angle grinder takes seconds) where the crack was, and fill with 3M 5200 between masking tape lines, 1/4" above and below.

Marine Hull/Keel Join Repair" target="_blank">

[ramblinrod]

Addendum.

After the keel / hull join is fixed. Grind all the rust off the keel to bright metal, and sand the rest very course (40 grit). Immediately apply 4 heavy coats of epoxy primer/barrier (I use Interlux Interprotect E2000) and when the final coat is still green (cured to point still tacky but doesn't transfer onto your glove) apply the anti-fouling. (It looks like your boat currently has Interlux VC17 on it. Good choice for the Great Lakes).

If it were my boat, having been in fresh water all its life, I would just retorque the keel bolt nuts, fix the smile, get rid of the rust (as above).

In general, your anti-fouling looks kinda crappy, so I would recommend stripping, primer coat if no signs of osmosis, barrier coat if their is, and fresh VC17.

If your not so worried about performance and appearance, just scuff sand, apply a fresh coat of VC17 and go.

If you don't want to do it, bring your boat up to Lake Ontario in the fall and give me call. (Sorry about the gratuitous solicitation folks, can't help myself.) ;-)