Keel Bolt / Stud Leaking

Harry Brown said:
It does look like a new leak and the bolts are probably fine, but I think I'm going to have to take the Keel off to be sure.
I would love to just re-torque, but then I will never know if the bolts are corroded or not.
I just need to find out items needed and correct procedure to carry out the task.
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Before dropping the keel think it is worth lifting in slings to inspect. The keel face is quite narrow there - hence the single bolt so the sealing area is small. If the seal has failed, pretty sure it will be obvious when the keel is hanging - showing as a line on the join. You may be able to slack off the nut, open out the seal and inject new sealant before retightening the nut with new sealant under the nut.

If you do have to drop the keel a competent yard will know how to support it and the boat while it is off the keel. There is a bulkhead just in front and just behind the keel.
 
My boat was previously owned by the sail training organisation, of which I am a member. From time to time, when the boat was mentioned to other members they remark "Oh, yes that boat always had a mysterious intermittent leak that nobody could trace"
During early sails in her I did not encounter any ingress of water, but eventually began to notice what seemed to be ever-increasing leaks which appeared to be coming from the region of the keel bolts. The decision was taken to consult the boatyard and they also concluded that the keelbolts were at the root of the problem.
The keel was dropped and rebedded, (no sign of rust), and the boat relaunched. Everything seemed to be fine when tied up alongside, so I arranged to sail her from West Cork to Dublin. Before too long we discovered that there was still a leak, but with careful detective work we discovered, during the course of the passage, that what was happening was; that there was a seepage of water from the head outlet skin fitting that was non-existant on starboard tack, barely discernible when level but quite copious when on port. The incoming water was disappearing under the inner liner when on port, then seeping out of a limber hole in one of the "ribs" and pooling in the area of the keel bolts when level or on starboard. So, all can sometimes not be what it seems:)
 
Spirit of Glenans said:
My boat was previously owned by the sail training organisation, of which I am a member. From time to time, when the boat was mentioned to other members they remark "Oh, yes that boat always had a mysterious intermittent leak that nobody could trace"
During early sails in her I did not encounter any ingress of water, but eventually began to notice what seemed to be ever-increasing leaks which appeared to be coming from the region of the keel bolts. The decision was taken to consult the boatyard and they also concluded that the keelbolts were at the root of the problem.
The keel was dropped and rebedded, (no sign of rust), and the boat relaunched. Everything seemed to be fine when tied up alongside, so I arranged to sail her from West Cork to Dublin. Before too long we discovered that there was still a leak, but with careful detective work we discovered, during the course of the passage, that what was happening was; that there was a seepage of water from the head outlet skin fitting that was non-existant on starboard tack, barely discernible when level but quite copious when on port. The incoming water was disappearing under the inner liner when on port, then seeping out of a limber hole in one of the "ribs" and pooling in the area of the keel bolts when level or on starboard. So, all can sometimes not be what it seems:)
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Yes indeed.Adding to my earlier post I should say that some investigation is warrented.
 
Don't take this as gospel, but I think I'm right about this.

On some Bavarias (and I think the 39 was the worst for this) the hull flexes when it's lifted and a gap appears between the back edge of the keel and the hull (the keel is quite thin at this point and there is only 1 stud in the middle). There is information on the BOA website about it.

So it could well be that where it was lifted in, water got through the gob and the stud, and once it's settled down it's re-sealed itself.

I also seem to remember that there were cases of people over-tightening the nuts and causing damage to the hull.

Again, don't take this as fact, but please ask around (other 39 owners, and surveyors). Maybe also give Anne-Marie a call at Clipper and ask her to ask the maintenance crew if they know anything about it.
 
I'm sure you appreciate all the wise advice you've been getting - but it's mostly (as far as I can see) from enthusiasts who, probably, have no naval architectural training and haven't seen the leak.
I'd suggest that:-
a) it could be serious, but not obviously so
b) such leaks are not unknown on that particular boat
c) it is salt water, only occurs when sailing, and doesn't happen when the boat is moored and not moving.

None of the suggested actions would appeal to me as owner or as skipper - I'd need to be certain of the reason for this intermittent leak.
Assuming the boat has just been bought, one would presume you had a full survey done. If that is the case, it would be politic to invite the surveyor to assess the evidence and make an exploratory visit. After all it's his PII you'll be claiming on if he didn't notice a major fault.
If you haven't engaged a decent naval surveyor, now is the time to do so, before hauling out, inspecting keel joints etc.
 
charles_reed said:
I'm sure you appreciate all the wise advice you've been getting - but it's mostly (as far as I can see) from enthusiasts who, probably, have no naval architectural training and haven't seen the leak.
I'd suggest that:-
a) it could be serious, but not obviously so
b) such leaks are not unknown on that particular boat
c) it is salt water, only occurs when sailing, and doesn't happen when the boat is moored and not moving.

None of the suggested actions would appeal to me as owner or as skipper - I'd need to be certain of the reason for this intermittent leak.
Assuming the boat has just been bought, one would presume you had a full survey done. If that is the case, it would be politic to invite the surveyor to assess the evidence and make an exploratory visit. After all it's his PII you'll be claiming on if he didn't notice a major fault.
If you haven't engaged a decent naval surveyor, now is the time to do so, before hauling out, inspecting keel joints etc.
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I may be just an enthusiast :) but do have some experience with boats and ,especially on a boat of this size and type, common sense applies more than anything else. A thourough investigation will make the reason obvious and I really don't think one needs to be a naval architect to detect and understand the causes behind the problem.This is after all a fairly simple structure not a state of the art built to the minimum weight, maximum strength racing machine.
Making this a matter that only experts of the highest level can understand is not in the spirit of the forum or for that matter of the practical boat owner. My opinion of course. As an enthusiast.
 
Just got this back from Bavaria (in their wording):

"• You have to solve the keel bolts and then you can remove the keel. It could be difficult therefore the keel sticks on the hull, gelcoat and Laminate will be damaged during there process.
• Keel and hull must be cleaned with Aceton and you have to use a primer.
• The type of sealant is called "Plexus". Information you find under http://www.selvida.de/epages/62442099.sf/de_DE/?ObjectID=2997077
• I have no Information about the size of the nuts and the torque is 360."

I'm a little bit disappointed with their response really.
I've ask them to clarify if they mean foot pounds, or newton meters (the latter I expect). But what does worry me is the bit about "the keel sticks to the hull and there will be damage upon removal"
It looks like these are stuck on, with probably the Plexus stuff they are referring too.
How am I going to remove the keel with minimal damage if it is stuck on? Has anyone had any experience with removing a bonded keel from a hull?
 
Harry Brown said:
Just got this back from Bavaria (in their wording):

"• You have to solve the keel bolts and then you can remove the keel. It could be difficult therefore the keel sticks on the hull, gelcoat and Laminate will be damaged during there process.
• Keel and hull must be cleaned with Aceton and you have to use a primer.
• The type of sealant is called "Plexus". Information you find under http://www.selvida.de/epages/62442099.sf/de_DE/?ObjectID=2997077
• I have no Information about the size of the nuts and the torque is 360."

I'm a little bit disappointed with their response really.
I've ask them to clarify if they mean foot pounds, or newton meters (the latter I expect). But what does worry me is the bit about "the keel sticks to the hull and there will be damage upon removal"
It looks like these are stuck on, with probably the Plexus stuff they are referring too.
How am I going to remove the keel with minimal damage if it is stuck on? Has anyone had any experience with removing a bonded keel from a hull?
Click to expand...
Modern sealants are so effective that the keel may very well stay firmly stuck.Damage to the laminate is very likely.I would lift the boat and inspect the joint area with the keel not touching the ground. If there is no opening of gaps I'd think that you can get away with just removing the offending stud ,with the boat resting on the keel , injecting as much sealant as it will take, refit the stud and tighten.As I understand it the bolt is the aft single one isn't it?
 
30boat said:
Modern sealants are so effective that the keel may very well stay firmly stuck.Damage to the laminate is very likely.I would lift the boat and inspect the joint area with the keel not touching the ground. If there is no opening of gaps I'd think that you can get away with just removing the offending stud ,with the boat resting on the keel , injecting as much sealant as it will take, refit the stud and tighten.As I understand it the bolt is the aft single one isn't it?
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That's correct, it is the aft single one. It is a stud though. Does anyone know if it is possible to extract the stud using the lock nut method?
Also, I don't know if injecting sealant into the hole will just fill the extracted stud hole and not the keel itself. I like the idea though.
 
I'm not a boatbuilder but, assuming the keel isnt in danger of falling off, (there are several other bolts with no leaks, probably dual, rather than single), you are really looking to seal the route by which the water is getting in?

If removing the keel is going to cause damage, then the stuff holding it on, and sealing most of the gaps, is going to be pretty well stuck.

So why not lift the boat, grind out a bit of whatever is in the region of the bolt that is leaking, and fill it with sealant, or GRP, or the Plexus stuff, in addition to removing the bolt/stud, fill the hole up with sealant, (or other stuff), doing something to force it into any gaps at the bottom of the hole, then refit the bolt/stud, and make things better locked down at the top end - bigger washer/s, bigger nuts, ???.

There will be a boatbuilder way of doing what I'm describing, but it doesnt seem like rocket science.

Given what Bavaria are saying about the damage that would be caused removing the keel, I think you would be buying lots of trouble, and risking leakage from other bolts/studs after refitting etc..
 
Harry Brown said:
That's correct, it is the aft single one. It is a stud though. Does anyone know if it is possible to extract the stud using the lock nut method?
Also, I don't know if injecting sealant into the hole will just fill the extracted stud hole and not the keel itself. I like the idea though.
Click to expand...

I wouldn't worry too much then.It's the end of the keel and the hull is flexible there. The locknut method should work well with your stud.I removed all the studs on a smaller Bavaria that way and had no problems..Filling the hole in the keel is what matters after all as it will exclude water from the stud avoiding corrosion issues in the future.
 
I wouldn't worry too much then.It's the end of the keel and the hull is flexible there. The locknut method should work well with your stud.I removed all the studs on a smaller Bavaria that way and had no problems..Filling the hole in the keel is what matters after all as it will exclude water from the stud avoiding corrosion issues in the future.I still think that a larger plate washer would help.
 
If the stud is screwed into a blind hole in the keel the hydraulic effect will most likely prevent you from screwing the stud in again if you fill the hole with sealant, unless there is some route for it to escape.



Coating the stud with sealant in the region of, and a little below, the hull to keel joint may well have the desired effect,
 
Bobc said:
Don't take this as gospel, but I think I'm right about this.

On some Bavarias (and I think the 39 was the worst for this) the hull flexes when it's lifted and a gap appears between the back edge of the keel and the hull (the keel is quite thin at this point and there is only 1 stud in the middle). There is information on the BOA website about it.

So it could well be that where it was lifted in, water got through the gob and the stud, and once it's settled down it's re-sealed itself.

I also seem to remember that there were cases of people over-tightening the nuts and causing damage to the hull.

Again, don't take this as fact, but please ask around (other 39 owners, and surveyors). Maybe also give Anne-Marie a call at Clipper and ask her to ask the maintenance crew if they know anything about it.
Click to expand...

What is the BOA website? Ive googled but not sure what it stands for.

Also, who is Anne-Marie at Clipper. I can't seem to find that either.

Thanks
 
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Harry Brown said:
What is the BOA website? Ive googled but not sure what it stands for.

Also, who is Anne-Marie at Clipper. I can't seem to find that either.

Thanks
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BOA os the UK Bavaria Owners Association. Bob is a leading light. £15 a year (I think) to join

Anne-Marie runs the service department at Clipper Marine in Swanwick.

Several of us have suggested that you lift the boat to inspect the seal between the boat and the keel before you do anything. As the earlier thread shows this is not an unusual issue with that model for the reasons mentioned and you should be able to seal the bolt hole to prevent the leak without removing the keel.

There is an article in this months PBO on keel issues which has (among other things) a photo of chisel marks on a keel that was removed. They are really stuck on well - one of the reasons why generally they give no problems. The article makes it clear that few of the reported keel losses are due to bolt problems, so while the leak is annoying, it does not mean any structural issues, and pretty sure it can be cured relatively easily.
 
VicS said:
If the stud is screwed into a blind hole in the keel the hydraulic effect will most likely prevent you from screwing the stud in again if you fill the hole with sealant, unless there is some route for it to escape.







Coating the stud with sealant in the region of, and a little below, the hull to keel joint may well have the desired effect,
Click to expand...
good point.
 
Well, I have had this response back from Bavaria confirming my questions about the 360 torque setting and the sealant/compound to use, this was the response. I have also attached a link to the Installation Manual below

https://drive.google.com/file/d/0B0TJ4TnMDd6BX0cyT0xHc1JWSG8/view?usp=sharing

"It is 360 Newton Meters (Nm). Yes the right sealant is Plexus MA 310 (incl. Metallprimer).
Attached you find a Manual to install a keel which I found in our data base.
If there is one bolt leaky only normally it is enough to loose the bolt, clean it, grind the laminate around the bolt and make it tight with Sikaflex, Epoxy or Plexus."

So, they seem to think if it is just one bolt leaking, and I assume because of the age of the boat (2007), I'm good to clean and reseal.

I'm sure some people aren't going to be happy about this!
Thoughts?.....
 
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