Keel Bolt / Stud Leaking

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Harry Brown

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I have a 2007 Bavaria 39 Cruiser.
I'm looking for some guidance for stopping an intermittent leak from the aft keel bolt / Stud. (confirmed, definitely not leaking from anywhere else).
Has anyone had experience with this? Can I just re-torque the bolts or is removing / installing the keel the way to go?
I would assume removing the keel, to check everything is OK would be the best option, but if someone knows better, I would consider that!

Depending on the best solution, would anyone have or be able to explain the procedure / equipment needed please? i.e. keel trolley, compound used between mating faces, torque settings etc, etc.
I am capable of doing the job and looking forward to rectifying ASAP. The job would be carried out using a boat lift.
If no one has the procedure for Bavaria, maybe they know of a different type of vessel, that the procedure is similar?

Many thanks in advance for your help with this matter.

[/URL]
Bolt.jpg
Click for picture^
 
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If you're getting water ingress at the bolts, it shows that water is entering at the joint between keel and hull. This is a BAD THING because water can get at the bolts and cause corrosion. It has to be sealed at the joint although sealing at the bolt head is OK as a temporary expedient.
When removing the keel, remember its very heavy and needs care when handling.
 
have you had opportunity to look at the hull/keel joint with the boat out of the water ?

An intermittent leak from the aftmost keel bolt alone would make me think

1 lower nut not torqued down sufficiently (to be honest it looks very new, and I would be more comfortable with a small washer beneath the nut to spread the load to the large washer), with - possibly - badly installed mastic

and worst case

2 the boat has run into something while moving forward, and the impact has opened a gap at the back of the hull/keel joint. Have a look for witness marks at the leading edge of the keel.

How long have you had the boat ? Is the leak with the boat stationary (tied up) or just when sailing ?
 
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The boat is new to me. Was completely dry until the first sail. Noticed it when I got back. Panicked, thinking what ever am I going to do!
It let in about a 1-2 liters of water, slowly, over 2 days, until the 3rd day it stopped, and it is now bone dry again!
Its not a bad / fast leak, but wrong, and I obviously want to rectify it ASAP.
 
Harry Brown said:
The boat is new to me. Was completely dry until the first sail. Noticed it when I got back. Panicked, thinking what ever am I going to do!
It let in about a 1-2 liters of water, slowly, over 2 days, until the 3rd day it stopped, and it is now bone dry again!
Its not a bad / fast leak, but wrong, and I obviously want to rectify it ASAP.
Click to expand...

Probably a stupid question but are you sure it is coming from the keel bolt. I remember spilling a few litres of water and for the next few weeks it worked it's way around the inner skin on my Bavaria 38 and appeared in the general area you are talking about. Had to wick it out in the end. Only ask as if the boat was on the hard any spilled water may have gone to the bow or stern and only made it's way to the middle of the boat when you lifted her back into the water. This would also explain why it is now dry?
Apologies if it is definitely coming from the keel bolt.
 
My experience has been that water coming up through keelbolts is usually rusty because it has come across the iron keel on its way. Your water appears to be clear, suggesting that it may have come from elsewhere. I assume you have tried tasting it?
 
Clean water suggests that is a recent leak because there is no rust staining. Would first check that the nut is tight. It is not uncommon for a grounding to deform that area of the hull without showing much visible signs. A gap can then open up at the keel joint when sailing. To check the boat needs to be lifted in slings for inspection. On the hard with the boat sitting on the keel the gap closes.
 
I look again at the newness of the stud, washer and bolts. Have they been replaced recently ? If so, when/why.

The video shows ingress from somewhere along the keel/hull joint. But with modern mastics not 'taking up' like oakum, I am uncertain why the leak has stopped. If you get the boat out and inspect the joint, that may give you a clue, especially if it is weeping.

Have you put a torque wrench on the bottom nut to see if it is properly tight ? From another forum, 150 - 200ft.lbs (200 - 275 Nm) seems to be reasonable. If the after bolt is slack, then the others may be, as well. At least the bilge is sparkly clean, which again tends to suggest this is a recent phenomenon, or someone has cleaned up on purpose....


As Tranona points out, sitting on the keel will compress the joint, and the bolt heads change from tension to compression, so look carefully as the boat is lowered onto the keel and see there is any external distortion of the joint, and if the bolt heads inside move.
 
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jordanbasset said:
Thanks for the video, can I jut confirm there is no drainage hole to the left of the keel bolt, I have watched the video several times and it appears to come from there from about 2 seconds in. Apologies again if there is no hole, just looked that way, perhaps I am looking too hard
Click to expand...

You are correct, there is a drainage hole just forward of the Bolt, and it does look that way as the water fills up the lower point right by the hole first, but the bay the other side is completely dry.
I wish the water was from a different source, but it is 100%, from the bolt.
 
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You could withdraw the bolt, a bit or completely. There are other bolts holding the keel on, and any water ingress will be evident very quickly so you could screw it back down again. It might be seawater, but it could still be from elsewhere?
 
Tranona said:
Clean water suggests that is a recent leak because there is no rust staining. Would first check that the nut is tight. It is not uncommon for a grounding to deform that area of the hull without showing much visible signs. A gap can then open up at the keel joint when sailing. To check the boat needs to be lifted in slings for inspection. On the hard with the boat sitting on the keel the gap closes.
Click to expand...

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.
 
Harry Brown said:
You are correct, there is a drainage hole just forward of the Bolt, and it does look that way, but the bay the other side is completely dry.
I wish the water was from a different source, but it is 100%, from the bolt.
Click to expand...

Okay, understand, it was just the similarity, that is almost identical to what happened in my Bav 38 and it also only came into the one side into where the keel bolt was
 
sarabande said:
I look again at the newness of the stud, washer and bolts. Have they been replaced recently ? If so, when/why.

The video shows ingress from somewhere along the keel/hull joint. But with modern mastics not 'taking up' like oakum, I am uncertain why the leak has stopped. If you get the boat out and inspect the joint, that may give you a clue, especially if it is weeping.

Have you put a torque wrench on the bottom nut to see if it is properly tight ? From another forum, 150 - 200ft.lbs (200 - 275 Nm) seems to be reasonable. If the after bolt is slack, then the others may be, as well. At least the bilge is sparkly clean, which again tends to suggest this is a recent phenomenon, or someone has cleaned up on purpose....


As Tranona points out, sitting on the keel will compress the joint, and the bolt heads change from tension to compression, so look carefully as the boat is lowered onto the keel and see there is any external distortion of the joint, and if the bolt heads inside move.
Click to expand...

The Bilge, Studs & Nuts, were really quite dirty, I cleaned everything up when when trying to prove it was not a bolt leaking, you could eat your dinner off it down there now!!!

The only reason I can think of that the leak has now stopped is that the keel has settled, pulling the nut, washer and yellow compound down, therefore sealing it. When sailing the keel moves and the process starts again.

I haven't tried re-torquing as yet, as I am trying to decide what to do.
 
Harry Brown said:
The Bilge, Studs & Nuts, were really quite dirty, I cleaned everything up when when trying to prove it was not a bolt leaking, you could eat your dinner off it down there now!!!

The only reason I can think of that the leak has now stopped is that the keel has settled, pulling the nut, washer and yellow compound down, therefore sealing it. When sailing the keel moves and the process starts again.

I haven't tried re-torquing as yet, as I am trying to decide what to do.
Click to expand...

The reason why the leak is intermittent is that there is movement and one stud alone is not enough to cause it so I would think that removing the keel is a wise decision. Make a cradle with a very wide base to keep the keel upright and the forces low.Welded square or rectangular section steel tubing would be my choice of material but wooden beams work just as well. Use a polysulphide or a MS sealant and you won't go wrong. Plenty of it! I would also make decent rectangular plate washers,those pretty rounded ones look too small. As for torque be aware that the studs seem to be quite small in section (http://www.wermac.org/bolts/bolts_bolting-torque-tables_stud-bolts_flange-bolt-up.html ),It's not a difficult job,just a bit laborious.
 
Also the leak is probably happening when the boat is on one tack only from the forces on the keel and hull hence dry when not in use
 
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