Keel Bolts

[teacherspet]

I just got the survey on a Hunter Legend 40.5 and it states "Some bonding terminals/connections have corrosion, inspect and service the entire bonding system. The keel to hull joint has a small crack aft, clean and keep dry, adjust keel bolts. Service the entire bonding system, some corrosion on the wiring terminals." This is the only issue with Geico Marine insurance and it states it needs to be repaired to be insured. So, asking for guidance. Is this something to walk away from and say no deal? How much would a repair like this cost? Do they have to drop the keel to fix this?

 

[Don S/V ILLusion]

Simple matter to torque keel bolts to ensure integrity and clean bonding connection. The 40.5 has a stub keel so a picture of where the crack is would help.

Your biggest problem isn’t cost but reaching those bolts in the deep keel requires a special torque wrench and extension. Nothing costly.

 

[teacherspet]

Thanks for your reply, It is deep and the yard hopefully will have the extension and the torque wrench.

 

[teacherspet]

Simple matter to torque keel bolts to ensure integrity and clean bonding connection. The 40.5 has a stub keel so a picture of where the crack is would help.

Your biggest problem isn’t cost but reaching those bolts in the deep keel requires a special torque wrench and extension. Nothing costly.

 

[Don S/V ILLusion]

Looks like that isn't where the keel attaches to the stub. Might be stress crack.

 

[jssailem]

Upon seeing the images, my first impression is the keel struck something. If it is on the stern en of the keel, I would inspect the stern bottom of the keel for damage. I would look inside in the keel well at the bow end for compression damage. Keel bolts that are loose might also provide information. Think about the physical action that occurs when the keel hits a rock and how it moves trying to stop the movement of the boat. It is like a teeter-totter with one end moving one way and the other moving in the opposite direction. The end attached to the boat compresses the fiberglass. The boat absorbs the force and stops. Stress cracks remain.

 

[DianaOfBurlington]

Nine times out of ten it’s a stress crack. Correctly done, the keel is attached by the factory using 5200. One prime attribute of 5200 is that it is phenomenally strong as an adhesive (the 5200 holds the keel on. The bolts just hold it till the 5200 cures. I know this from first-hand experience).

Another attribute is that 5200 stays flexible. Since this therefore will always a flexible joint, any attempts (like I made on mine) to trowel hard fairing compound over it will result in hairline cracks that grow bigger. This is fondly referred to as ‘the Hunter smile’. It’s a fact of life.

The best treatment is to take your Dremel with the little stone half-football and to grind that crack into a very fair groove maybe 3/16” wide and 1/8” deep around the whole keel/hull joint. This is not like chasing cracks in the deck or topsides. It’s a real seam and you will not see the end of it. Just make room for 5200.

Chemically and physically clean this with a small wire brush and then acetone like the lives of everyone you know depend on it. Go inside and do a ‘final’ keelbolt adjustment (NO MACHINES. As with anything involving 5200, go to your first grunt when using your 8” ratchet wrench. Then YOU ARE DONE).

Go back outside and apply a nice neat bead of 5200 into the clean groove. It’s okay to push it in with your finger. It’s okay to have it stand a little proud after - actually best if you do.

Wait a full week or more (note I did NOT say ‘use Fast Cure’). Then when you apply bottom paint DO NOT use a wire brush on the bead. DO NOT sand it. And DO NOT wipe with alcohol (Achilles heel of 5200). Just blot with acetone and paint it.

In future, examine it every season. If it’s falling out you didn’t clean it well enough. You’ll have to re--do THE WHOLE THING.

 

[DianaOfBurlington]

As for your corrosion problem, guess what? - ALL ELECTROLYTICAL BONDING SYSTEMS INDUCE CORROSION. They’re made of bimetallic connections in a wet area like the bilge and carry continuity with outside seawater.

First question: why do you have a bonding system? Because you have multiple metals underwater. I have ONE piece of metal underwater: the rudder stock. All the through-hulls are Marelon. The little outboard has its own zincs. There are NO anodes anywhere else and NO internal bonding system.

If you have bronze seacocks, there’s your problem. Necessary evils like the Garmin triducer can (should) be epoxy-coated before installation. Same with the rudder shaft (as long as you know it’s type 304. Should be). The engine has its own internal zincs and there’s a football collar on the prop shaft. And the shaft and strut should be epoxy-coated before being painted with Smart Solution antifouling.

Avoid all bared metal in the bilge. Avoid all wiring in the bilge. Carry bilge-pump wiring in its casing way up out of danger before heat-shrinking a tinned-copper connector to it. Same with transducers. Lube all keel bolts with marine lithium grease/antiseize. Maintain a dry bilge.

The bonding system is essentially archaic and follows the adage of ‘hair of the dog’ - approach the problem with a bit of the problem. No underwater metal = no problem.

It’s not because my H25 is small and simple that I say this. I’ve done the same thing on Cherubini 44s. The two examples are not irrelevant to each other.

‘Simplify, simplify, simplify. Then add lightness.’ - Colin Chapman; Lotus Cars.

‘Weight plus complexity plus expense equals NOT sailing.’ -JC (after my dad).

 

[teacherspet]

Nine times out of ten it’s a stress crack. Correctly done, the keel is attached by the factory using 5200. One prime attribute of 5200 is that it is phenomenally strong as an adhesive (the 5200 holds the keel on. The bolts just hold it till the 5200 cures. I know this from first-hand experience).

Another attribute is that 5200 stays flexible. Since this therefore will always a flexible joint, any attempts (like I made on mine) to trowel hard fairing compound over it will result in hairline cracks that grow bigger. This is fondly referred to as ‘the Hunter smile’. It’s a fact of life.

The best treatment is to take your Dremel with the little stone half-football and to grind that crack into a very fair groove maybe 3/16” wide and 1/8” deep around the whole keel/hull joint. This is not like chasing cracks in the deck or topsides. It’s a real seam and you will not see the end of it. Just make room for 5200.

Chemically and physically clean this with a small wire brush and then acetone like the lives of everyone you know depend on it. Go inside and do a ‘final’ keelbolt adjustment (NO MACHINES. As with anything involving 5200, go to your first grunt when using your 8” ratchet wrench. Then YOU ARE DONE).

Go back outside and apply a nice neat bead of 5200 into the clean groove. It’s okay to push it in with your finger. It’s okay to have it stand a little proud after - actually best if you do.

Wait a full week or more (note I did NOT say ‘use Fast Cure’). Then when you apply bottom paint DO NOT use a wire brush on the bead. DO NOT sand it. And DO NOT wipe with alcohol (Achilles heel of 5200). Just blot with acetone and paint it.

In future, examine it every season. If it’s falling out you didn’t clean it well enough. You’ll have to re--do THE WHOLE THING.

I wish I had read your post before today. I do believe you are correct, it was a stress crack since it is 2.5 feet above where the bolts are located, but since the survey said adjust the bolts, that is what insurance wanted and when the yard went to do so, they sheared the bolt off

 

[MFD]

Out of genuine curiosity, and not expecting you to know for sure…

My understanding is that the process for re-torquing the keel bolts is to back it off, inspect/clean, then re-torque, and there is a little bit of grace to be used when getting to the final limits rather than simple brute force with a 48” bar on the socket.

Did the yard personnel provide you with the measurements from around when it failed? Would be something like foot-pounds or Nm.

They should have been doing that if the boat is on the hard - the limit would be the pre-tension as specified by the factory, and if not available, the size and material of the bolts themselves.

 

[DianaOfBurlington]

I wish I had read your post before today. I do believe you are correct, it was a stress crack since it is 2.5 feet above where the bolts are located, but since the survey said adjust the bolts, that is what insurance wanted and when the yard went to do so, they sheared the bolt off

They sheared off the bolt because they incorrectly assumed that they were dealing with something like wheel lug nuts or cylinder head bolts which are stressed metal-to-metal connections with non-compressible gaskets. They did not do what I advised and to trust well-applied structural flexible adhesive and to go to only ‘first grunt’ like I said.

This kind of yard is what makes member boards like sailboatowners.com necessary and so popular.

RULE NO.1: if the yard doesn’t have a widely-held and well-deserved reputation for providing first-class knowledgable service on keelboats (i.e., they are predominantly a motorboaters’ yard) don’t go there.

You can apply this rule to all your vendors including your insurance company.

 

[teacherspet]

They sheared off the bolt because they incorrectly assumed that they were dealing with something like wheel lug nuts or cylinder head bolts which are stressed metal-to-metal connections with non-compressible gaskets. They did not do what I advised and to trust well-applied structural flexible adhesive and to go to only ‘first grunt’ like I said.

This kind of yard is what makes member boards like sailboatowners.com necessary and so popular.

RULE NO.1: if the yard doesn’t have a widely-held and well-deserved reputation for providing first-class knowledgeable service on keelboats (i.e., they are predominantly a motorboaters’ yard) don’t go there.

You can apply this rule to all your vendors, including your insurance company.

Well, they did not use a torque wrench at all. Unfortunately, the Insurance stated it needs to be fixed for the boat to be insured. Now I am in a rock in a hard place, since I was going by a survey that may be incorrect on "adjust the keel bolts," and as you stated, the boat yard used brute force. I am contacting a maritime lawyer because the yard said they could do the job @ $500.

 

[dlochner]

A common misconception about keel bolt torque is to torque to the bolt's specifcation. Torquing to that specification can crush the fiberglass and damage the keel. Sabre recommends only 90 lbs of torque for all of their boats. Far less that than the 1+" diameter bolts can withstand.

 

[DianaOfBurlington]

Well, they did not use a torque wrench at all. Unfortunately, the Insurance stated it needs to be fixed for the boat to be insured. Now I am in a rock in a hard place, since I was going by a survey that may be incorrect on "adjust the keel bolts," and as you stated, the boat yard used brute force. I am contacting a maritime lawyer because the yard said they could do the job @ $500.

This is a good application of the term ‘that sucks’. I worry that the insurance company is going to look at a 43-year-old boat and an experienced yard and wonder what did you expect? - like the whole boat could fall apart next week anyway. Like I said above about picking your vendors.

On the positive side, you have options. If you don’t trust the 5200 (mine was compromised by an inexperienced yard before I got the boat) you could part the hull from the lead and re-bed it (what I did). If the 5200 is good you might just sail around with one bolt dead. As I said it’s the 5200 that holds the keel on. The bolts are for locating the keel on the hull. It is highly likely that you’ll never experience any problem retaining only 7 of 8 bolts.

The easiest option to please the insurance company would be to drill a new long deep hole through the bottom and into the lead. Fit threaded inserts into the lead and screw a threaded rod into the lead (with epoxy on). Install new lock nuts and inspect regularly. And never apply more than ‘first grunt’ to that one - or to the other ones.

Your last resort (structurally best option) is to lift the boat off the keel, send out the lead to be recycled and have a new one (with new keel bolts in) made. And I truly don’t think that’s as costly as you’d fear. We’ve done it with several Cherubini 44s. Remember the lead guys get to have your old lead. And lead is one of the cheapest precious metals anywhere. I’d bet you could have this done for the yard bill and 2/3 the price of new lead. The labor could be done in any good sailboats yard. And by rights the insurance company and the yard idiots should pay for that.

 

[DianaOfBurlington]

A common misconception about keel bolt torque is to torque to the bolt's specifcation. Torquing to that specification can crush the fiberglass and damage the keel. Sabre recommends only 90 lbs of torque for all of their boats. Far less that than the 1+" diameter bolts can withstand.

See my point about the 5200 and going to ‘first grunt’ again. Seriously - the boat wasn’t built with very much obsessive specifications. If you went into Hunter’s factory in 1979 they’d be like ‘What torque wrench?’ Seriously.

 

[teacherspet]

This is a good application of the term ‘that sucks’. I worry that the insurance company is going to look at a 43-year-old boat and an experienced yard and wonder what did you expect? - like the whole boat could fall apart next week anyway. Like I said above about picking your vendors.

On the positive side, you have options. If you don’t trust the 5200 (mine was compromised by an inexperienced yard before I got the boat) you could part the hull from the lead and re-bed it (what I did). If the 5200 is good you might just sail around with one bolt dead. As I said it’s the 5200 that holds the keel on. The bolts are for locating the keel on the hull. It is highly likely that you’ll never experience any problem retaining only 7 of 8 bolts.

The easiest option to please the insurance company would be to drill a new long deep hole through the bottom and into the lead. Fit threaded inserts into the lead and screw a threaded rod into the lead (with epoxy on). Install new lock nuts and inspect regularly. And never apply more than ‘first grunt’ to that one - or to the other ones.

Your last resort (structurally best option) is to lift the boat off the keel, send out the lead to be recycled and have a new one (with new keel bolts in) made. And I truly don’t think that’s as costly as you’d fear. We’ve done it with several Cherubini 44s. Remember the lead guys get to have your old lead. And lead is one of the cheapest precious metals anywhere. I’d bet you could have this done for the yard bill and 2/3 the price of new lead. The labor could be done in any good sailboats yard. And by rights the insurance company and the yard idiots should pay for that.

On the Legend 40.5, the boat has only three bolts. Trying to find information on how long the bolts need to be. A machine friend told me about McMaster and Carr; they have 316 Stainless steel bolts. Thanks for the input, I will try to do some research on what you stated about melting it down and making a new one, but I do not think we have anyplace close by where I live in Florida

 

[Tally Ho]

On the Legend 40.5, the boat has only three bolts. Trying to find information on how long the bolts need to be. A machine friend told me about McMaster and Carr; they have 316 Stainless steel bolts. Thanks for the input, I will try to do some research on what you stated about melting it down and making a new one, but I do not think we have anyplace close by where I live in Florida

Wow, and I thought the bolts on my O’Day 322 were “sparse”…I have 4. 3 are 1” and one is 3/4”.

The yard sheared off 1” bolts?

Greg

 

[heritage]

Have you visually checked the broken bolt for signs of crevice corrosion?

 

[DianaOfBurlington]

Wow, and I thought the bolts on my O’Day 322 were “sparse”…I have 4. 3 are 1” and one is 3/4”.

The yard sheared off 1” bolts?

Greg

I think this makes a very strong case for my long-held and empirically-proven point that the 5200 holds the keel on.