E38 Keel Bolt Project

[u079721]

All this talk of keel surgery makes me glad I wasn't able to be around at the yard when mine was done years ago. Mine was one of those boats where the factory apparently did not remove the mould release from the hull prior to bonding the keel, and reportedly when the yard removed the nuts and lifted the hull the keel dropped away with no hesitation at all.

In my case they used epoxy to re-bed the keel, so God help the next person who has to try and remove it!

 

[Cory B]

Dropping the Keel

To get the keel to drop on our boat, they had the boat in the travel-lift, and had the keel locked down in the "keel holder contraption". They then very gently torqued the boat side-to-side until it broke free. Took about 15 minutes. There was no damage to the keel or shoe. I really don't know what was holding it on, the latex(?) sealant certainly didn't look strong enough.

 

[Frank Langer]

OK, so can one of you experts explain....

OK, so given how much trouble several owners are experiencing in dropping their keels as described above, I'm wondering if most keels are held on this tight or is this an exception. If most are like this, are we being overly cautious in rebedding our keels, as even if the bolts corrode, it looks like the keels aren't going to budge.

I know preventive maintenance is important and has it's place to avoid worse trouble later. Maybe the forces on the keel when sailing are so strong that they would break the keel off if the bolts were corroded.

I can also understand that until one tries to drop the keel, one doesn't know how solid it is, and it may vary by boat, so to be safe one has to drop it, even if it would have been strong enough to last without doing that if there were a way of knowing in advance. I can accept that argument.

Can anyone with engineering or similar expertise comment on the forces on a keel, and convince me that the effort these owners are going to to rebed their keel is really required.

Thanks.

Frank.

 

[Cory B]

Sticky Keels

Frank,

I think even a poorly attached keel with rusty bolts will do just fine in mostly static conditions, like sitting at the dock or in a travel lift. When trying to drop the keel we all try to be really gentle as not to damage anything. I'd imagine the forces on them increase by orders of magnitude when heavily heeled over or in a rough seaway. That being said, even with half-rusted keel bolts most boats would probably be just fine sailing in protected waters.

Also, there was another case posted on the site where the issue wasn't that the keel was imminently falling off, but just letting way to much water in the boat.

I also think the problem feeds on itself... a little saltwater sneaks in, rusts the bolts a little, allowing more water to seep in... Best to nip in the bud early if you have any doubt.

In our case I have absolutely no doubt that it was the right thing to do.

Heres hoping you never have have to go through it.

 

[Maine Sail]

OK, so given how much trouble several owners are experiencing in dropping their keels as described above, I'm wondering if most keels are held on this tight or is this an exception. If most are like this, are we being overly cautious in rebedding our keels, as even if the bolts corrode, it looks like the keels aren't going to budge.

I know preventive maintenance is important and has it's place to avoid worse trouble later. Maybe the forces on the keel when sailing are so strong that they would break the keel off if the bolts were corroded.

I can also understand that until one tries to drop the keel, one doesn't know how solid it is, and it may vary by boat, so to be safe one has to drop it, even if it would have been strong enough to last without doing that if there were a way of knowing in advance. I can accept that argument.

Can anyone with engineering or similar expertise comment on the forces on a keel, and convince me that the effort these owners are going to to rebed their keel is really required.

Thanks.

Frank.

Frank the problem is in what you can't see. As polyurethane sealants age (5200 is a polyurethane) they can become brittle, lose much of their original flexibility and even though still tenaciously adhered, in many places, can crack and allow water into the keel bolt area. Remember almost all keel bots are surrounded by bilge water on the top side and ocean or lake water on the out side and are 100% dependent on the sealant to keep water out.

Keels are under tremendous loads and do flex! Over time as the polyurethane sealant ages and the keel continues to move and flex against the keel stub water finds it's way to the keel bolt. At this point crevice corrosion sets in and goes to work on the keel bolts. Crevice corrosion is a very dangerous but ever present condition in a good majority of boats out there plying the waters. Unfortunately, most owners don't even know what crevice corrosion is or that a keel should be re-set on occasion.

This photo of crevice corrosion depicts why it is important to drop and re-bed a keel every so often:

When I did my keel on my old Catalina 30 the 5200 was just as Rob described somewhat brittle but still holding in many places. Unfortunately, there were many cracks from flexing that had let water get at my keel bolts and destroy them!

In my experience 5200 DOES NOT remain flexible and pliable, to it's original spec, for the life of the boat!!!

 

[Martin King]

If most are like this, are we being overly cautious in rebedding our keels, as even if the bolts corrode, it looks like the keels aren't going to budge.

Yes, you need the keelbolts if your keel is external. If your keel is
encapsulated like on the 39,37, 36C, 31C etc. then it's a non issue.
I'm not sure when Ericson abandoned using what they called
mush to bed the keels as well as decks. Basically it was a
thickened resin and in the 70's they were using powdered asbestos
in the mix! To wash the goop off their hands, the workers would
dip them in cans of acetone! But I digress. The bedding compound
may very well be this mush that's preventing the keel from dropping
if the boat is 70's-early 80's.

 

[rwthomas1]

Update:
Well, I used the super long hole saw today. It worked really well, too well in fact. I smoked my Makita 1/2" drill using it. I was able to saw down maybe 1"-1 1/4" before the saw would just slow/stop due to lack of power from the drill. I have a larger drill to try tomorrow. Anyone know the thickness of the keel stub floor? I am guessing 1 1/2" or so? I must be pretty close. The smell of the saw cutting and heating up the bedding compound is foul. I mean toxic make you gag foul. I have a headache after doing it so I think maybe it was not really healthy.

I am not overly concerned about widening the holes in the keel stub. The hole saw fit pretty tightly around the bolts so the clearance will likely end up 5/16" or so in total on each bolt. Additionally while using the saw it was quite apparent that the material being cut was not really fiberglass! I think the holes were bigger then we all think from the factory. Regarding the clearance, when reattaching the keel this area will fill with whatever bedding is used and then effectively locate the keel

The compound that was used to bed the keel is not like anything I have seen before. It turns to very dry coarse dust when cut with a sawzall. It appears like some sort of thickened resin as it has that mottled appearance as if it was thickened with chopped glass. It also kills the best sawzall blades available in minutes. Occasionally I get a whiff of polyester smell and sometimes sulfur so who knows! I've got a little experience with old 5200, etc. and this seems different. I don't think debonder will do anything as likely this is not 5200.

Regarding the question of dropping the keel or not. I had some concern after reading about some of the keel issues on this board. I also had a nice rust bleed on 3-4 keel bolts/washers. On the outside before I started messing with it there was visible parting line between the keel/hull forward and aft but not really in the middle. On the port side in the middle there was a one foot section of visible parting line and it had a rust colored tinge to it. Not a full blown bleed but rust nonetheless. Considering that 4-5 keel bolts have thread corrosion visible and the issues above existed I think that dropping the keel is the correct thing to do. Given the trouble I am having I think the keel would likely have been just fine for many more years. The problem is, how long until the issues I have found become failures? No way to know. The only way to know for sure is to drop it. So here I am.

I am at a bit of a loss at this point as I half expected the keel to loosen up a bit every time I have tried something new. I will return to the boat tomorrow and bring a more powerful drill to deepen the cuts until I hit lead. I am not sure I want to beat on the keel bolts with a sledgehammer. I am worried that they may just compress in the lead or bend to the side. 304 stainless is relatively soft. After deepening the saw cuts I am going to try oak wedges hammered into the crack fore and aft.

If anyone has any other ideas I'd love to hear them RT

ps-Don, yes thats a Blade CP tailrotor. Had I taken that shot from the other direction you would have seen a eCCPM conversion ARK X400.... I can't do much other than hover but its fun!

 

[knewthomas]

She Has Dropped!!!!

Just a quick update...Last night we were very glum about this keel coming off the boat, but Rob went back today armed and dangerous. I'll let him post the details when he's able. He called to say the keel finally dropped and he only smashed two fingers with a sledge. Can't wait to get out of work to check on Rob & Ruby. I guess tomorrow the yard will lift the hull so we can really inspect the bolts.
Thanks to everyone for all your encouragement and suggestions. We needed every bit of it. Unfortunately this is only the first step!
Cheers,
KT

 

[u079721]

Pictures!

Pictures! After all this suspense, we wants lots of pictures!

 

[rwthomas1]

As my lovely bride has posted, yes the keel is down! I don't have pics as there is only maybe 1 inch of space to nothing to see yet. The hole saw was used to deepen the cuts around each bolt until we hit lead. My business partner and I tried various oak wedge schemes to no avail. What finally worked was a log splitting wedge and a 12lb sledgehammer. Beaten into the parting line about 18" back on the port side. This resulted in some fairly ominous creaking sounds then the keel dropping. It didn't do as much damage as I expected to the keel or the fiberglass. The lead is a bit displaced but that is easy to beat back to shape, glass in is a bit chipped, but its a keel stub not the topsides.

The keel was glued on with some sort of very strong adhesive, I am guessing epoxy. Someone had been here before as the "sump" in the keel casting was filled with expanding foam! A small section of the keel stub fiberglass was actually torn away, as Maine Sail mentioned it might be. Not a huge deal. There is evidence of a softer flexible sealant around the keel bolts and the much harder epoxy on the mating surfaces.

My thoughts on this are a previous owner found keel bolt damage and didn't want to fix the bolts so the keel was cleaned up and glued on with the best product they could find to give them peace of mind. The keel bolt damage I could see looked like older damage, but what do I know....

Hopefully tomorrow the yard will lift the hull and I can get to the cleaning/scraping this weekend and the pics everyone wants to see.

The bad part is I got two fingers, #3 and #4 on my right hand caught behind a large oak block that was summarily smacked with the above mentioned 12lb sledgehammer. This happened in the first 5 minutes of my day. After working all day like this I went to the Doctor. Both fingertips are broken, very swollen and quite purple. I think this post is enough hunting and pecking for one day.

Thanks for all the help and support. Pics when I get to the next phase.

RT

 

[Dferr]

Glad to hear that the keel finally dropped and only two fingers were smashed! Reading all of this really has me anxious to see if mine is going to be as stubborn. I really hope not, because I have so many other things going on - Nevertheless, I'll get it done!

Congrats!

Don

PS - Did I ever tell you that boats suck?

 

[rwthomas1]

You wanted pics! The pic with the corroded bolt is the worst one. The question is, is it bad enough to worry about? Some of the bolts were ground down a bit by the hole saw cutting but this is all below the nut engagement area. Let me know what you think about the corroded one. I will try to take a wire wheel to the bolts this weekend to see how bad the corrosion really is. RT

 

[Dferr]

Rob -

I personally don't think your keel bolts look that bad - I hope mine look that good. The one with the corrosion you could probably cut and add a coupling nut with a new piece of threaded rod. As far as I know right now, I only have one corroded bolt like you do, also in the same area as yours, and that's my plan, to just couple that one bolt, if need be.

By the way, I read an article by Don Casey saying that Polysulfide is the best bedding compound for almost anything on your boat if you want to be able to remove it ever again. I was checking into Sikoflex 291 Lot but I'm not sure yet.

Let me know what you decide -

Any way, glad to see the keel is off!!

Don

 

[Maine Sail]

Rob -

I personally don't think your keel bolts look that bad - I hope mine look that good. The one with the corrosion you could probably cut and add a coupling nut with a new piece of threaded rod. As far as I know right now, I only have one corroded bolt like you do, also in the same area as yours, and that's my plan, to just couple that one bolt, if need be.

By the way, I read an article by Don Casey saying that Polysulfide is the best bedding compound for almost anything on your boat if you want to be able to remove it ever again. I was checking into Sikoflex 291 Lot but I'm not sure yet.

Let me know what you decide -

Any way, glad to see the keel is off!!

Don

Damn Rob those look fairly good. I've seen guys build them back up with a welder then re-cut new threads and that may be an option.

If it were me I might just clean and chase the threads and put it back on. When we did my keel we cut a U shaped groove around the keels perimeter about 1/2" in from the edge of the keel and all the way around and about 3/16" deep. This moat surrounded the keel bolts and gave a nice thick gasket of sealant. The thicker the sealant the more flex it can handle, and longer lasting the gasket will be. 500% elongation at break of 1/64 of an inch is not much movement but 500% elongation at break of 3/16 of an inch is quite a bit..

My keel was put back on with Sikaflex 291. 291 is not a polysulfide but rather a polyurethane like 5200 & 4200 but similar to 3M 4200, in adhesion, although it's a little less tenacious than 4200. I guess you could call 291 3200 if 3M made one...???

If you want a great polysulfide 3M 101 is one of my favorites...

 

[Gary Peterson]

If you decide to use a coupling bolt and new stainless rod to extend into the boat, the coupling bolt needs to be twice the bolt diameter in length.
For example; with stainless 1" bolts, each bolt section needs to be threaded a minimum of 1" or so into the coupling bolt for maximum strength.

In looking at the corroded bolt, I would be very hesitant about not repairing it. To me it doesn't look very safe.

 

[rwthomas1]

I did some chipping/chisel work today on the keel stub bottom and also wire wheel work on the bolts. Almost all bolts have some minor pitting and most have a small section of thread missing here and there. The only bolt with reduced section width is the one in the above pic. The reduction is only 25% of the bolt.

I got to meet JohnK today, very nice fellow, and he seemed to agree that the keel bolts look pretty good. Even the reduced one is likely workable. I also spoke with the yard manager who stopped by. He also agreed that the bolts looked better than expected and that the reduced bolt wasn't a major concern. He had two suggestions: One is to clean the bolts and fill with a "liquid metal", an epoxy that the yard uses to restore metal engine parts -OR- check and see about getting a welder to weld up the bolts. Either way the bolts would then be re-threaded with a die. The phone calls/research will begin in earnest on Monday.

I don't think I would use a coupler and new threaded section. I would likely sleeve the offending bolt and fill the corroded cavity with thickened epoxy. That bolt still has plenty of strength, no reason to cut it off entirely.

After this I would use a passivating paste and then coat the bolts with epoxy up to the height of the keel stub thickness.

The bolts will receive new double-thickness nuts and 1/4" stainless washers or fabricated backing plates. The double-thickness nuts will spread the clamping load to more of the threads.

Ericson keels are overbuilt when compared to other brands. I have looked at C&C, O'Day and Catalina so far and the keels are held on by fewer and smaller bolts, in general. Given, I do believe that Ericsons are built better however it is pretty clear that having one keel bolt that is undersized by 25% is not a liability.

I have more pics, I just have to upload them.

RT

 

[JohnK]

...One is to clean the bolts and fill with a "liquid metal", an epoxy that the yard uses to restore metal engine parts -OR- check and see about getting a welder to weld up the bolts. RT

Yeah -JB WELD! I had a diesel rabbit back in the day with a cracked water pump. A little JB and it lasted 2 more years until I could dump the car off on my sister!

I definitely concur on the condition of your bolts. None, in my view, need to be replaced. Whichever method you pick, the keel will be good to go for another 20 years. Let me know if I can help at all.

 

[Gary Peterson]

Rob,
If you do decide not to repair that bolt, I would suggest before you reinstall the keel, to double nut it and torgue the upper nut to 350 lbs/ft to see if the bolt is strong enough. Better to find out then than after the keel is bedded and you are torquing the nuts in the boat.

(We in the engineering field would call this FMEA-failure mode engineering analysis)!

Just my opinion______

 

[rwthomas1]

Gary,
That is a good idea. I am still not overly concerned about the bolt. I will likely sleeve that bolt just to be sure. Something will be done to that one and the minor imperfections on the others will be filled in.

Just basing my experience against that size of bolt, I have worked on quite a few diesel engines where the harmonic damper is torqued to 250-300ft/lbs. These fasteners were much smaller. Doubtful that the keel bolt will have any problem with the torque.

RT

 

[JohnK]

I have a 300 ft/lb torque wrench (and sockets, extensions, u-joints, etc.) from my keel-ordeel last year. Let me know.