Keel bolts problem

[gillesroy209]

I recently purchased a Bavaria 47 2001. After a few months of preparation, we were ready to leave from Port Antonio Jamaica for Willemstad, Curacao. The first leg of our trip from Montego Bay to Port Antonio went without any problems. Upon leaving Port Antonio,
within 30 minutes, my wife screamed that we were taking on water. It was to the floorboards and splashing around. Inspection of Through-hulls, seacocks, the rudder, the saildrive, the bow thrusters and all connections to the belly of the beast revealed nothing. All seacocks had been closed prior to departure. the closed floorboards revealed that water was coming in in the boxes containing our keel bolts. When this was discovered, we were in 10 to 15 knot winds with 3 to 5 foot waves, nothing bad. As soon as we righted the boat, the ingress of water seemed to stop.

I found out that in 2004 or about that time, Bavaria changed their sealing process, from an epoxy glue to 3M 5200 which not only seals but also has some memory to compensate for the flexing of the keel.

This is the process I would like to use. I have tried to remove the keel by removing the nuts and using a tractor to seperate the keel from the hull to no avail. I will be using wedges to separate them.

A word of caution: at the time my bilge pump did not do its job because the water did not stay long enough in the bilge for it to prime. Second, I came to realize that some holes were made between the baffles and water got into those which sends the water behind the structure. With a hand pump and a small tube we were able to remove most of it which turned out to be in the neighbourhood of 50 gallons.

Does anyone have thoughts about the material I should use to rebed my keel to the hull? Has anyone encountered the same issue with a Bavaria? This is the first time that I have seen this kind of problem with a modern boat.

Thank you in advance for your help and advice on the procedure.

 

[Tom Metzger]

Have you talked to Bavaria?

 

[PaulK]

Bavaria had a problem with ballast keels coming off a couple of years ago. This is probably something you want to have fixed right.

 

[Alex Dare]

keel removal

My understand was that the lost keel problem was confined to the Match series from Bavaria. I believe the Match 36 but not positive. As for removing the keel on your boat I would think twice (or three times) about using wedges to separate it. The keel is not that wide at it's attachment point to the hull and any damage done by the wedges to the mounting surfaces could affect proper reattachment. What you don't want is a sloppy, less than flat joint that could allow additional movement once the keel is reattached. In many cases a hydraulic jack can be used inside the boat along with some beams and strapping/chain to apply pressure to the keel bolts and literally push the keel loose. I have also seen very stuck keels loosened with the creative use of a travelift and a skilled operator. In either case make sure you find someone who's done this before. That being said my first call would be to Bavaria to see if they have a recommended procedure for removing stuck keels.
Re-bed with 5200 is pretty much the norm.

 

[jibes138]

Before using wedges, you have a lot of surface area (I assume) between the keel and the keel stub of the hull. 3M 5200 has very high bonding strength so the forces to remove it will be very high. Wedges may cause significant damage to the glass of the keel stub before it breaks loose. Just a suggestion but i would take some wire with some grit on it and try sawing my way through the bondline until you hit the keel bolts. Work your way all around the keel to separate as much of the bond strength as possible before trying to mechanicall remove the keel. Also search on the site for other keel projects, about a year ago there was a great set of pictures from a member that did a keel refit job.

 

[Roger Long]

3M 5200 has very high bonding strength so the forces to remove it will be very high.

You can say that again. When installing this through hull backing block with 5200, I wondered about glassing it in.

According to the published 5200 data, the 6" x 6" block would lift twice the weight of the boat.
Although the plywood itself probably would de-laminate first, I figured that was good enough.

 

[RAD]

Go to the search feature on this site and type keel saga by the author Charlie Cobra

 

[tommays]

IMHP your boats keel leak issues are a bit more seriious that just droping and rebeding the keel

Something has had to happen to allow the joint to open and let in that much water

I have seen extra long hole saws made that fit around the keel bolts to cut away what ever sealent was used when the keel was installed

With the large amount of bolts on a 47' boat this alone would cause a huge problem if done correctly

 

[Maine Sail]

the closed floorboards revealed that water was coming in in the boxes containing our keel bolts. When this was discovered, we were in 10 to 15 knot winds with 3 to 5 foot waves, nothing bad. As soon as we righted the boat, the ingress of water seemed to stop.

Please be sure that it's your keel bolts leaking and not something else. I strongly doubt that this much water would come in through a leaking keel bolt and have never seen nor heard of that unless the keel was literally dangling.

Check your bilge pump first. PO's and builders often do not install high loops or siphon breaks and they back siphon when heeled and the outlet drops below water.

Plug your bilge hose then sail her on her ear and see if you can repeat the problem and start with a bone dry bilge. For that amount of water to come in the keel bolts should still be leaking significantly even at rest and with the boat "upright". Many builders use epoxy to bed keels, Sabre is one, and I have not seen nor heard of many failures.

 

[RAD]

Please be sure that it's your keel bolts leaking and not something else. I strongly doubt that this much water would come in through a leaking keel bolt and have never seen nor heard of that unless the keel was literally dangling.

Check your bilge pump first. PO's and builders often do not install high loops or siphon breaks and they back siphon when heeled and the outlet drops below water.

Plug your bilge hose then sail her on her ear and see if you can repeat the problem and start with a bone dry bilge. For that amount of water to come in the keel bolts should still be leaking significantly even at rest and with the boat "upright". Many builders use epoxy to bed keels, Sabre is one, and I have not seen nor heard of many failures.

My best friend was sailing a brand new Catalina 30 on her maiden voyage when the exact problem happened out in the Atlantic.......it was the bilge discharge without a loop and thank God someone went down below to pee cause it was a nice summer night and every one was in the cockpit and the water level was pretty deep
I believe this might be the same seneiro.....hope he's not busting his balls trying to separate the keel from the hull at this moment

 

[gillesroy209]

my bilge exhaust is in the transom, and at no time is it under water, unless I get a wave from aft. I was close-hauled at the time. Also, my boat has 11 seacocks, 2 through-hulls, 1 rudder and a 120c saildrive. At the time of water ingress, every single one was checked
and they were all dry. Only the compartments where the keel bolts are got flooded.
I did contact Bavaria, with very little success. One dealer in Swizerland told me that they were aware of a similar issue. But the factory won't acknowledge anything.

Please be sure that it's your keel bolts leaking and not something else. I strongly doubt that this much water would come in through a leaking keel bolt and have never seen nor heard of that unless the keel was literally dangling.

Check your bilge pump first. PO's and builders often do not install high loops or siphon breaks and they back siphon when heeled and the outlet drops below water.

Plug your bilge hose then sail her on her ear and see if you can repeat the problem and start with a bone dry bilge. For that amount of water to come in the keel bolts should still be leaking significantly even at rest and with the boat "upright". Many builders use epoxy to bed keels, Sabre is one, and I have not seen nor heard of many failures.

 

[Maine Sail]

my bilge exhaust is in the transom, and at no time is it under water, unless I get a wave from aft. I was close-hauled at the time. Also, my boat has 11 seacocks, 2 through-hulls, 1 rudder and a 120c saildrive. At the time of water ingress, every single one was checked
and they were all dry. Only the compartments where the keel bolts are got flooded.
I did contact Bavaria, with very little success. One dealer in Swizerland told me that they were aware of a similar issue. But the factory won't acknowledge anything.

Do you have a picture of the keel to hull joint?

 

[gillesroy209]

Initial try

Thank you for your input.
I have removed the nuts from the 13 M20 SS bolts. I can see that the bolts were threaded into the keel (they are not J bolts) and bedded into the hull with epoxy.The service department at Bavaria sent me a drawing of the keel and bolts and the first bolt aft is not where the drawing says it should be, because with a grinder I removed the Sikaflex that was sealing the keel and I can see it in a 3 or 4 millimeter gap. One other thing I noticed is that the drawings which were approved by Lloyd's registry specify M24 bolts and 17 of them instead of the M20 and 13 that I have. I wonder if this change could have an impact on the integrity of the assembly. 13 instead of 17 is a 23.5% reduction and M20 instead of M24 means something like 29.7% less strenght. If those two conditions are added it represents 53% less strenght, no wonder this has happened.
I have requested a procedure from Bavaria which I won't get until Tuesday because they have a big boat show in Germany this weekend. I wish I could go there and tell them what I think of their engineering department. Obviously this has to do with cost reductions more than customer safety

My understand was that the lost keel problem was confined to the Match series from Bavaria. I believe the Match 36 but not positive. As for removing the keel on your boat I would think twice (or three times) about using wedges to separate it. The keel is not that wide at it's attachment point to the hull and any damage done by the wedges to the mounting surfaces could affect proper reattachment. What you don't want is a sloppy, less than flat joint that could allow additional movement once the keel is reattached. In many cases a hydraulic jack can be used inside the boat along with some beams and strapping/chain to apply pressure to the keel bolts and literally push the keel loose. I have also seen very stuck keels loosened with the creative use of a travelift and a skilled operator. In either case make sure you find someone who's done this before. That being said my first call would be to Bavaria to see if they have a recommended procedure for removing stuck keels.
Re-bed with 5200 is pretty much the norm.

 

[kloudie1]

Sounds like the engineering was OK but the construction was not what the engineers specified !! Probably would be good to document with pictures and notes and try to get Bavaria to help with the cost of repairs.. The request can escalate through the US Govmint Consumer Protection folks..?? Even though it is an older boat what you are seeing is a gross neglegence thing.. that was done in their factory making the product unsafe.

 

[tommays]

Jboat keel

Its a bit strange to haul a leaking boat and not have fairly Obvious dammage

When we hit the rock this spring on the C&C 35 and started taking on water it was sure not leaking through the bolts BUT a big crack two feet behing the keel

 

[jibes138]

I think if you check the tensile strength of the bolts you will likely find that one of the bolts is strong enough to support the entire keel in tension. The keel is in bending so the analysis is a bit more complex. The abundant number of bolts is to keep the face of the keel in contact with the hull while in a bending as opposed to just holding the keel vertically by supporting its' own weight. Not sure I'd jump to conclusions about the keel bolts being the problem, unless you can see where the keel has separated allowing water to ingress. The keel bolts plus the adhesive strength of the bedding compound whould be adequate to support the keel. Is there any sign of damage to the bottom of the keel that would suggest a hard hit from a grounding? As Tommay's picture shows I have seen several boats damaged from hard groundings (rocks) and the hull is usually fractured behind the keel. Do you have any pictures of your situation to share?

 

[jibes138]

Here's a back of the napkin. A M20 bolt has a minimum minor diameter about 16.24 mm. Dividing by 25.4 then squaring the result, multiplying times pi and dividing by 4 gives about .33 square inches. If we assume a conservative 50,000 psi tensile strength for the stainless steel the bolt will hold about 16,821 pounds in tension. Times 13 is 218K pounds. How heavy is the keel in the boat? A 47 is a big boat with a heavy keel. Once again in bending the loads on the screws will be a lot higher than a static tensile load..