Keel Bedding Survey

[DaveBMusik]

After removing the wood from my keel stub and repairing with layers of fiberglass, I dropped my keel to check the keel bolts but found them fine.  I rebedded with 5200 (don't think there will be a problem in the future LOL) and put a couple layers of fiberglass around the keel seam.

[Indian Falls]

I did mine 13 years ago with 5200.  No leaks.  No smile.  I however, did not refair the joint all the way around to make it pretty.  I wanted to wait to see if I had success and to really let the stuff settle.  Then another 11 years went by.  I just put a little fresh VC-17 on it and make plans for next year.  My procedure is in the tech wiki.  The rust is from the iron "cast in lead" lifting points.  The smile in my own opinion was from not enough glue in there in the first place and too much backstay tension coupled with keel bolts that had never been checked for torque.

http://c34.org/bbs/index.php/topic,6842.0.html

[Ron Hill]

dan : Disagree with you on the cause of the smile.  I talked to the factory many years ago and they recommend that the boat be blocked with 75% of the weight on the jack stands/cradle and 25% of the weight on the nose of the keel.  Also VERY important to get the jack stand pads on the bulkhead!!

A few thoughts

[pbyrne]

dan : Disagree with you on the cause of the smile.  I talked to the factory many years ago and they recommend that the boat be blocked with 75% of the weight on the jack stands/cradle and 25% of the weight on the nose of the keel.  Also VERY important to get the jack stand pads on the bulkhead!!

A few thoughts

Ron, do you think this could be the cause of the fairing flaking off in my other thread?  Sorry to hijack a bit... hopefully you know what I'm referring to Ron!

[KWKloeber]

I have for a long time disagreed with the thought (Catalina factory fantasy) that smiles are due to the blocking.

You have two planks that do NOT bend (the flat top surface of a hefty lead keel) AND a box beam constructed in the bilge stub.  You are NOT going to bend the keel stub by shifting more or less weight forward or aft on the keel.  For a crack to open, on one end the non-bending beams would need to open up, which creates a "V" to the ether end of the non-bending beam.  It doesn't happen.

Besides, what happens to the "tender joint" (that according to CTY cannot resist being loaded by so-called mis-blocking it) when the keel is NOT supported (i.e., with (literally) tons of stress on it, while being kicked to and fro and back and forth while tacking and crashing through swells while heeled?
That doesn't create more dynamic stress on the joint than statically loading it (by so-called mis-blocking it)?

[Ron Hill]

Guys : I've heard Gerry Douglas say a number of times, "You have never heard of a keel falling off a Catalina Sail Boat"!!

A thought

[girmann]

Ron,

I'm not one to disagree with you and your experience, but the mechanical drawing from Catalina shows blocking only on the front of the wing keel. Mine is a Mk.II, so there might be a difference, but for Mk.II wing keels, all the weight should be on the front of the keel only. Next time I'm down at the boat, I'll take a picture.

Mark

dan : Disagree with you on the cause of the smile.  I talked to the factory many years ago and they recommend that the boat be blocked with 75% of the weight on the jack stands/cradle and 25% of the weight on the nose of the keel.  Also VERY important to get the jack stand pads on the bulkhead!!

A few thoughts

[KWKloeber]

all the weight should be on the front of the keel only.

blocked with.... 25% of the weight on the nose of the keel. 

Mark,
You didn't say what % of weight should be on pads vs the keel, but, above, parsing out the pertinent information ... You both are saying the same thing. 

Weight should be supported at the nose (ie., forward part of) the keel. ***

I trust that you are not saying there should be no weight on pads (be it jack stands or a cradle)???

PS: ***Do not read into this that I buy into CTY's fantasy explanation of what causes a smile.

[girmann]

You are absolutely right. I (mis)read his post three times before answering and still got it wrong. Thanks for the correction. I had this fight with the yard last fall and couldn't see what he was actually saying.

all the weight should be on the front of the keel only.

blocked with.... 25% of the weight on the nose of the keel. 

Mark,
You didn't say what % of weight should be on pads vs the keel, but, above, parsing out the pertinent information ... You both are saying the same thing. 

Weight should be supported at the nose (ie., forward part of) the keel. ***

I trust that you are not saying there should be no weight on pads (be it jack stands or a cradle)???

PS: ***Do not read into this I buy into CTY's fantasy explanation of what causes a smile.

[High Current]

I have for a long time disagreed with the thought (Catalina factory fantasy) that smiles are due to the blocking.

Actually I buy it.  My old hunter had a smile too.  I filled/faired with G/flex and sailed for a season.  At haul out, hanging in the travelift slings, I was eager to see how it had held up.  Perfect.  An hour later she was on the stands and the seam had been cracked open.

[KWKloeber]

I have for a long time disagreed with the thought (Catalina factory fantasy) that smiles are due to the blocking.

Actually I buy it.  My old hunter had a smile too.  I filled/faired with G/flex and sailed for a season.  At haul out, hanging in the travelift slings, I was eager to see how it had held up.  Perfect.  An hour later she was on the stands and the seam had been cracked open.

But, that does not prove the original cause of the smile.  Just that a patch job didn't work.

Coincidence is not valid proof of causation.


Again, anyone who can logically explain how, using engineering principles of statics and mechanics, two unbendable beams can magically be made to bend, all while the same (and higher) stresses occur on the keel/joint (while sailing) and that does NOT cause the joint to open -- Have at it.

[KWKloeber]

The inconvenient fact that the CTY explanation ignores      is that there's a forward keel bolt, pre-tensioned and torqued to (give or take) 105 foot-lbs.

So, is CTY seriously suggesting that if the BUTT of the keel is loaded, the resulting stress at the NOSE of the keel stub elongates the bolt so that the leading edge of the stub and keel can separate?
Or perhaps CTY is implying that the J-bolt pulls out of its embedment in the lead keel.

It seems that it must be one of those two options (or both) for CTY's theory "to work."    And, the forward nut torque would change when the boat is lifted off its blocking.

I'm not saying that it's not good practice to load the keel nose vs. the butt, but as far that causing the smile,
"For every complex problem there is an answer that is clear, simple, and wrong."  -H. L. Mencken

[High Current]

Well, spring is here, and like all good boat projects, this one quickly got out of hand...

If you remember, I decided that sealing the "smile" from the outside and the bolt from the inside would be my course of action.  But I decided to seal the other bolts while I was at it.  The first thing I did was check torque and I discovered that only one nut required >20 ft-lb to tighten; even that one required less than 40     The aft-most nut was so loose my thumb turned it while I was scooping the literal sludge out of that compartment.  I strongly suspect, based on the undisturbed gelcoat over the washers, and based on the aforementioned sludge, that this is the first time in 34 years anyone gave these bolts any thought.

Next I removed all the bolts and cleaned under the washers to ensure I would get a good seal with Sikaflex.  This was a BIG project involving copious amounts of degreaser, acetone, and elbow grease.  The washers were set into the original gelcoat, which formed a surprisingly poor seal; I would say at least 50% of the surface area under each washer was a void.  There was no sealant around the nut / threads.  These voids were filled with grease and led to mild corrosion of the undersides of the washers.  The washer for the rearmost bolt, however, is almost completely gone, which explains why its nut (which was also heavily corroded) was so loose.  Luckily the stud appears mostly intact.  Around the studs I could see where bedding had squeezed into the holes from below.  Although it didn't fill any of them completely, it should have protected most of the invisible part of the stud from corrosion - if it's intact.  Whether or not that underlying bedding is still intact is the (hopefully less than) $64,000 question.

So I am once again hemming and hawing over whether to drop the keel.  On the one hand, I want to be comfortable that no further ingress is possible, and only a fresh bedding job above *and* below can make it a certainty.  Likewise, if the bedding is compromised, dropping the keel is the only sure way to dry it out before I seal it from above.  I observed some cracks much lower on the keel that had weeped some and had me worried, but I went back to a picture of haul-out and found they were already there.  Still, it does make me wonder if water can seep up behind the fairing and get to the keel-hull joint even if it looks solid.

On the other hand, the keel is clearly attached quite firmly if it managed not to crack more than it did with the bolts so loose.  That speaks to possible damage from and difficulty with separating it, and I'm placing a lot of trust in the yard to do everything right; a botched repair could create problem with something that appears solid now.  Removing the keel is also a costly job that could lead to more costly jobs on a 34 year old boat.  If the bedding hasn't failed I'm better off leaving it as-is.  But with the bolts having all been so loose...what are the chances?

It is bizarre to me that Catalina apparently did not seal the bolts from the top; for all the concern about sea water getting in from below, it seems too easy for water (including salt from the stuffing box) to compromise the top portion of the bolts.  Did they not realize crevice corrosion existed back in 1990?

I also think there's a compelling correlation between grease and corrosion.  For all that the studs look OK below the (bilge) water line, there's some rust and pitting at/above the water line on some of them.  If grease traps in water and keeps out oxygen, I could certainly see it facilitating crevice corrosion. 

Moral of the story:  keep your bilge clean, seal your bolts from the inside if you haven't already, and check torque often.  Also, take lots of pictures: you never know when you might be wanting that "before" photo.

[Noah]

Never thought about water coming FROM inside. I question that worry. I never consider gooping up bolts in the bilge years after keel install. Maybe? However, it is a "known" issue discussed here in the past, that you should remove any gelcoat from around the washers and nuts to prevent oxygen starvation which could cause corrosion.

[KWKloeber]

water coming FROM inside.

That's what attacks and eats up the "mung" keel bedding!
Been there, done that. 
Got the Tee shirt (and N-95 respirator.)