I discovered this fall that the seemingly minor smile in my C34 was weeping rust. To make matters worse, I came back a couple of weeks later and found that it was (a) still wet, and (b) had a drip of orange bilge antifreeze on the leading edge of the keel. :cry4`
I've already arranged with the yard to have the keel dropped + rebedded before launch, but now I'm agonizing over the "proper" way to re-bed it. I came across an earlier post that said Gerry Douglas recommended polyester or vinylester resin but I also read through a bunch of posts where people talked about using "Satan's glue" 5200. I can imagine both benefits and drawbacks to having a little flexibility.
So I want to know: if you ever had your keel dropped for repairs or inspection, what did you re-bed it with and how has it held up over time?
Alternately...am I going too far? Given it's a small crack that likely compromises only the frontmost bolt and there is ZERO evidence of grounding damage, I could just try to dry it, seal it inside + out, re-torque, and cross my fingers...
I removed the keel from our boat in the fall and spoke extensively with Catalina regarding the proper method of re-bedding it before doing so. Warren Pandy (with Catalina) said that Catalina currently uses an epoxy product from FGCI to attach the keels to their new boats. Here's the link to the product they use.
https://fgci.com/product/trowel-on-epoxy-fairing-putty/
Yes, it's a fairing putty, but it's grip is very, very strong.
Warren related a story where a customer wanted to switch the keel on a new boat from a deep keel to a wing keel and when they unbolted the keel and lifted the boat, the keel stayed attached. After much work with saws and chisels they ended up just using a sawsall with a long blade and cut thru the bolts and everything along the entire joint to remove the keel. This epoxy product grips tenaciously and is the exact product I'll be using to re-bed my keel.
Interesting personal note. I too unbolted the keel bolts and made a cut along the joint with a skill saw in as far as the blade would reach, we then lifted the boat with a travel lift and that keel just hung there and was like "Is that all you've got?" In the end I used a deep core bit and drilled down around the keel bolts until I hit lead and that did the trick, we lowered the keel without further issue. ***IMPORTANT NOTE***....do NOT attempt to remove the keel without drilling down around those bolts, you'll rip the bottom of the keel stub out and that just opens up a can of worms I'd rather not have to deal with. I humbly speak from experience on that last part.
The bedding compound that Catalina used to use (at least back in 1988) was a polyester resin, not an epoxy, and even though Warren stated that at 35 to 40 years the adhesive was probably due for inspection I found it to be gripping quite well!!!
Sorry I can't say I've already completed this method successfully, but it works well for new Catalina yachts, and that's good enough for me.
High Current,
As anyone on this board will tell you that's the famous "Catalina Smile", yours doesn't even look that bad. It's your boat, your call of course but I wouldn't drop the keel to fix it, seems a bit like killing ants with a sledgehammer. I'd just open it up with a grinder let it dry out and fill it with the fairing material of choice (I prefer West Systems) and you're good to go. Since your boat comes out of the water every winter you get to check it annually. When my boat goes into the water I'm not going to see that smile for another four years and in the 36 years I've had my boat it's never been a problem just a maintenance thing.
One more thought when you drop the keep it's basically reattached the same way it is now is there any guarantee the smile won't reappear at some point down the road?
Quotet's your boat, your call of course but I wouldn't drop the keel to fix it, seems a bit like killing ants with a sledgehammer. I'd just open it up with a grinder let it dry out and fill it with the fairing material of choice
That's about what I would do. Inspect, retorque keel bolts then fill and fair. Also see that the boatyard doesn't add to the problem by having too much pressure on the bow. Will probably be some redoing each year.
Jim
Eric : There are numerous post on how to repair the "Catalina Smile". Yours does not seem that bad. Your hull # and being a 1990 production you should? not have any wood fill in the keel step!!
The reason for the smile is improper blocking of the Hull!! You need to put weight on the Nose of the keel by screwing up the rear keel jack stands!!
A few thoughts
Current: what year is your boat? It makes a difference as to whether it has any wood in the keel stub.
High Current,
My earlier post addressed re-bedding the keel. But I did go back thru the information I've received from Catalina and see that they do in fact specifically address sealing up leaking keel bolts, which is pretty much exactly what you describe.
The fix involves nothing more than removing the keel bolt nut(s) and washer(s), cleaning up the area under them and then sealing the area with 3M 4200. They also say to put an "O" ring around the bolt and then reinstall the washer and nut and and re-torque to spec. This method and the standard Catalina Smile repair around the front of the keel should solve your issue without removing and re-bedding your keel.
You've listed your boat as a 1990 so you definitely do not have any wood in your keel stub and that's a very good thing.
Hope this helps you decide what to do.
Thanks everyone! @ewengstrom your description of removing the keel is giving me cold feet on my original plan - seems like more opportunity to do harm than good, *especially* if I'm entrusting the work to someone else.
When I bought the boat a year ago my conclusion was "just a Catalina smile". The bilge was full of water (on the hard) and the crack was dry. No big deal - I fixed one on my old hunter and they're just part of having a fin keel, right?
What reduced me to panic was realizing that the bilge is leaking and rust is weeping out, which means salt water has reached and is corroding at least one of my keel bolts. At least the antifreeze is rinsing it clean? :D I saw the Catalina tech note on resealing them, but the outside must be fixed as well or it's just hiding the real problem. Is crack filling with G/flex up to the task?
I think my plan will be to do the following, go sailing, and see how it looks next fall:
1) Reseal the keel bolt(s) from the inside
2) Let everything dry out for a few weeks
3) Grind + seal the crack with G/Flex
4) Torque the keel bolts
Thanks again for holding my hand!
Eric,
Solid plan, when you pull the boat next fall you can see how your fix is holding up. Based on my experience where my boat only comes once every four years I'd say your fix will probably last two or even three seasons.
Eric : Where I've seen trouble - is when there was water in the bilge and no antifreeze and the freezing split the PVC tube going thru the underside of the keel step. His fix was to seal off that tube which allowed any rain water coming down the mast to only collect in the bilge aft of the mast step!!
A thought
Ben,
What led me to remove the keel this winter was corrosion in the keel bolts, it was especially bad around the tops of several of the bolts and to the point where the tops of the bolts were completely corroded and threads were missing on several, even under the nuts. When I removed the nuts after the boat was hauled and blocked I found that when the boat was originally built and the keel attached, the holes for the bolts was drilled slightly oversized, that would make sense. But I could clearly see moisture in the gaps around the bolts and some corrosion around a few of the bolts going into the stub....so I concluded I could no longer trust the integrity of the bolts and that's why I pulled the keel.
Interesting note......so I pull the keel, and then clean up the bolts to really get a look at the whole bolt, I found that the bolt corrosion was bad above the bilge floor, but not so bad inside the keel stub. Honestly, I still would not have trusted the bolts based solely on the thread condition where it mattered most, inside the nuts....but the bolts themselves really weren't that bad.
A very possible source of the rust you are seeing could be the factory lifting points inserted in the keel when it was poured. There are two of them, one directly below the mast step and one about four inches behind the aft keel bolt. these inserts are not stainless steel and the forward one showed signs of rust. When the keel was attached, there was no special attention to filling or sealing these lifting points...so if water can get to them, they will rust!!!
My pain...your gain. Again, hope this helps you out.
Eric,
Totally understandable in your case, with corroded tops the only way to check the condition of the bolts was to drop your keel and inspect. It was probably as much for peace of mind as it was for the repair. Fortunately for Eric it doesn't sound like he's gotten to that point.
Kevin,
I tend to agree after the deep forensic dive I've done on my keel. I love having in depth knowledge of the keel at this point and am happy to share, like I said, my pain, others gain. :?
Everyone's boat and everyone's situation is different, but I tend to agree with Ben's choice of opening it up, drying it out and then doing the standard "Catalina Smile" repair along with sealing the bolts in the bilge would be my path.
Another "fun" experiment would be to remove the nut and send some compressed air down around the bolt while someone below checked for bubbles, escaping air, rusty water, etc.
I'd be curious to know if this would reveal anything...other than an obvious path for that bilge antifreeze.
Ben
My experience is that the plan may change once the grinding starts. I thought I had a simple smile fix -- but once I ground off the fairing and deeper, I found about a third of the length of the keel bedding (polyester mung) had turned into junk like saturated drywall. It just hadn't made its way out into and cracked the fairing yet. So I ended up dropping and rebedding the keel -- Gougeon Bros recommended 5200 to bed it, which is what I used. Then I wrapped the joint with epoxy saturated, 4" biaxial fiberglass and faired over that.
Jerry Douglas of Catalina Yachts also recommends 3M5200 to seal the keel to the hull stub!!
A thought
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.
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
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
Quote from: Ron Hill on March 17, 2024, 03:23:06 PMdan : 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!
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)?
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
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
Quote from: Ron Hill on March 17, 2024, 03:23:06 PMdan : 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
Quote from: girmann on April 24, 2024, 04:58:27 PMall the weight should be on the front of the keel only.
Quote from: Ron Hill on March 17, 2024, 03:23:06 PMblocked 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.
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.
Quote from: KWKloeber on April 24, 2024, 06:56:21 PMQuote from: girmann on April 24, 2024, 04:58:27 PMall the weight should be on the front of the keel only.
Quote from: Ron Hill on March 17, 2024, 03:23:06 PMblocked 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.
Quote from: KWKloeber on April 09, 2024, 08:33:56 PMI 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.
Quote from: High Current on April 24, 2024, 07:53:13 PMQuote from: KWKloeber on April 09, 2024, 08:33:56 PMI 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.
The inconvenient fact that the CTY explanation ignores :oops: 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? :donno:
Or perhaps CTY is implying that the J-bolt pulls out of its embedment in the lead keel. :shock:
It seems that it must be one of those two options (or both) for CTY's theory "to work." :think 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
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 :shock: 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.
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.
Quotewater 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.)
@High Anxiety
QuoteThe aft-most nut was so loose my thumb turned it
I've previously posted about my same experience re: the fingertight aft nut and keel bedding so many times that my head hurts every time I repost about it.
QuoteThe washers were set into the original gelcoat, which formed a surprisingly poor seal;
Are you thinking that CTY bolted-up the keel nuts/washers into wet gelcoat? Doesn't seem logical to me. What does, is the known issue on C-30s of torquing the nuts so many times that the washers compress the glass and bury themselves in the gelcoat.
QuoteWhether or not that underlying bedding is still intact is the (hopefully less than) $64,000 question.
hemming and hawing over whether to drop the keel.
IIWMB my hem/haw would not be whether to drop the keel -- rather, my first step would be to decide WHEN to determine if
I EVEN NEED TO drop the keel. That is, answer that question right now — OR just go sailing now and answer it in fall '24 / spring '25.
Nothing is going to change before then and the keel will not fall off if you put off finding that out.
Like engines, plumbing, electrical, and other systems: one should not play Whack-a-Mole and willy-nilly replace/fix before one troubleshoots, Troubleshoots, TROUBLESHOOTs.
(Then play "more-informed" Whack-a-Mole.)
Quotepossible damage from and difficulty with separating it, and I'm placing a lot of trust in the yard to do everything right
Removing the keel is also a costly job that could lead to more costly jobs on a 34 year old boat.
Removing the keel is lightyears distant from being rocket science.
If I did it with no previous experience in dismembering the appendage, (IMO only) any other idiot like me **should** also be able to.
It's nasty, laborious (but not "difficult") work.
Reattaching it takes
brain power (unfortunately I learned that the hard way.)
That said I'm unsure whether I would trust the yard with anything. Someone who blocks jack stands with 2x4s has (IMO only) questionable knowledge/conscientiousness and at worst doesn't care about their customers' yachts. Gimmeabreak -- don't they have lumber yards in ME?
Quotecheck torque often.
See above for (IMO) the danger of too-often and too-tighting of the keel nuts.
Keel nuts that are 40 ft-lbs shy do not cause the Catalina smile.
Previous info about my "no aft smile" and the loose aft nut (in no particular order):
https://groups.io/g/Catalina30/search?d=0&ev=0&p=recentpostdate%2Fsticky%2C%2C%2522keel%2522+AND+carbide%2C20%2C2%2C0%2C0&ct=1&startdate=&enddate= (https://groups.io/g/Catalina30/search?d=0&ev=0&p=recentpostdate%2Fsticky%2C%2C%2522keel%2522+AND+carbide%2C20%2C2%2C0%2C0&ct=1&startdate=&enddate=)
https://www.sailnet.com/posts/2051801875/
https://www.sailnet.com/posts/319785/
https://c34.org/search_gcse/?q=%22kwkloeber%22%20%22keel%22%20joint%20OR%20bedding%20OR%20carbide
https://c34.org/bbs/index.php?msg=97345
https://c34.org/bbs/index.php?msg=82156
https://c34.org/bbs/index.php?msg=81134
https://c34.org/bbs/index.php?msg=74413
https://c34.org/bbs/index.php?msg=71726
https://c34.org/bbs/index.php?msg=67529
My saga about reattaching the keel:
https://c34.org/bbs/index.php?msg=67822
Quote from: KWKloeber on May 05, 2024, 10:42:35 PMPrevious info about my "no aft smile" and the loose aft nut (in no particular order):
I think that the only way you will really know the answer to this question is if you have a mechanical engineering friend. Knowing that type, turn it into some kind of bet and offer them a case of their favorite beverage so they do a "Finite element analysis" of the keel/hull joint blocked in the front or blocked fore and aft.
Logic dictates that the bolt isn't stretching, but the piece of keel that sticks out forward of the forward most keel bolt can bend. I'm not saying it does bend, I'm saying it "could". FEA (finite element analysis) would tell you exactly how much force you would need to create a "smile"
Mark
Mola Mola
Mark
Just for context 'fer others I think you are referring to
https://c34.org/bbs/index.php/topic,11903.msg97457.html#msg97457
not
https://c34.org/bbs/index.php/topic,11903.msg97563.html#msg97563
(which links pertain to deterioration aft, not a fwd smile (which I did not have,) and my prior experience rebedding the keel joint material.)
-ken
Quote from: girmann on May 06, 2024, 12:25:37 PMQuote from: KWKloeber on May 05, 2024, 10:42:35 PMPrevious info about my "no aft smile" and the loose aft nut (in no particular order):
I think that the only way you will really know the answer to this question is if you have a mechanical engineering friend. Knowing that type, turn it into some kind of bet and offer them a case of their favorite beverage so they do a "Finite element analysis" of the keel/hull joint blocked in the front or blocked fore and aft.
Logic dictates that the bolt isn't stretching, but the piece of keel that sticks out forward of the forward most keel bolt can bend. I'm not saying it does bend, I'm saying it "could". FEA (finite element analysis) would tell you exactly how much force you would need to create a "smile"
Mark
Mola Mola
Guys : It doesn't take a Mechanical Engineer to have a travel lift operator set the boat down and improperly set the hull so you have a "Catalina Smile" in a second!! All he has to do is set the keel on the ground and let the hull rock back!! :cry4`
A thought
Ron mon ami, are you saying that you have personally witnessed your smile occurring "in one second"? All I have heard is that it was always claimed to occur over off-season storage, not "immediately."
I wonder how CTY's would square its explanation of the cause with the smile on my keel being at the aft end? Too much weight on the nose of the keel perhaps? More CTY fantasy.
I agree that it probably doesn't take an M.E. -- in order to deduce that the hefty hull/keel stub box-beam section (below) between the nose and the first bolt, will not bend in the short distance in front of the first bolt.
(M.E.s deal with moving objects, eivil/structural engineers deal with
mechanics/statics/strength of materials and stress/strain/bending under load.)
.
Ken : Maybe I haven't seen it in "a second", but I've seen it start in a few days!! That 5600 Lb. wing keel
stays put when it's on the ground!!
A thought
Quote from: KWKloeber on May 05, 2024, 10:42:35 PM@High Anxiety
I've previously posted about my same experience re: the fingertight aft nut and keel bedding so many times that my head hurts every time I repost about it.
Well, thanks for doing it one more time. I found your post quite helpful. I've read a lot of posts about keels, including a few of yours, but managed to miss the similarity with the aft nut.
QuoteAre you thinking that CTY bolted-up the keel nuts/washers into wet gelcoat? Doesn't seem logical to me. What does, is the known issue on C-30s of torquing the nuts so many times that the washers compress the glass and bury themselves in the gelcoat.
Maybe it's not gelcoat per se, but whatever brittle white material coats the bottom of the sump partially covered all of the washers, appeared to be original, and cracked free easily when I disturbed it. Photos below
QuoteThat said I'm unsure whether I would trust the yard with anything. Someone who blocks jack stands with 2x4s has (IMO only) questionable knowledge/conscientiousness and at worst doesn't care about their customers' yachts. Gimmeabreak -- don't they have lumber yards in ME?
No kidding. I have stories....
If I had time to do the work myself it wouldn't hesitate to DIY, but it's 4 hours away and I have young children who need me to pick them up from school every day. My main reason to re-bed NOW would be to preserve integrity of the bolts. BUT if I weren't going through this process I probably wouldn't be worrying about it...
QuoteSee above for (IMO) the danger of too-often and too-tighting of the keel nuts.
Keel nuts that are 40 ft-lbs shy do not cause the Catalina smile.
Does it crush the solid glass or only the wood core that I don't have?
I used to think similarly but managed to convince myself otherwise. Loose keel nuts put extra stress / strain on the keel-hull joint that could lead to cracks and water ingress. On the other hand, I agree that 65 vs. 105 ft-lb is probably enough pre-load either way; at 105 ft-lb = ~10,000 lbf, a single bolt could hold the entire keel if it were in pure, static tension.
Reasons in favor of re-torquing that I can think of:
1) Lead creep and other factors (see: corroded washer in my previous post) can reduce bolt tension over time
2) Low bolt tension can lead to uneven loading of the keel and excessive stress/strain in the joint, possibly compromising the joint / bedding
3) If a keel bolt has been severely corroded, I would rather have it snap off when I try to torque it on the hard than have it silently stop holding my keel.
------
(1) made me wonder: What's the coefficient of thermal expansion of our hulls? Does it matter at what temperature one torques the bolt? Were my bolts loose simply because it was April?
I'm going to assume the keel stub is one inch thick (0.0254 m).
This says CTE of fiberglass is 25E-6 m/m-C: https://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html 10 degC @ 1" would be 6.35E-6 m of expansion, or 0.025%. Stainless is pretty close but let's ignore that for now to get a worst-case.
If I assume some lubrication (because anti-galling), then 105 ft-lb is about 10,000 lb of clamping force ≈ 44kN. https://www.engineersedge.com/calculators/torque_calc.htm
The washers are 1 7/8" diameter. Crudely, that amounts to 0.00178 m^2. 44kN / 0.00178 m^2 ≈ 25 MPa of stress.
Finally, looking here, one presumes strain is fairly linear at about 1% per 40 MPa: https://www.researchgate.net/figure/Stress-strain-cure-for-fiberglass-Figure-6-The-stress-strain-curve-and-tyre-strip-for_fig4_305627338
Assuming I did it all right, 10C change in temperature causes 0.025% change in thickness which causes 1.8 MPa change in stress out of 25MPa total, before you consider that the stud is also contracting. So no, temperature isn't a huge factor. But that was fun!
Quote from: High Current on May 14, 2024, 08:26:16 PMMy main reason to re-bed NOW would be to preserve integrity of the bolts. BUT if I weren't going through this process I probably wouldn't be worrying about it...
Correction,
The Main reason .....
IF I EVEN NEED to rebed is...
I don't understand the foregone conclusion that you need to rebed (i.e., the bolts are compromised)?
QuoteDoes it crush the solid glass or only the wood core that I don't have?
at 105 ft-lb = ~10,000 lbf
≈ 25 MPa of stress.
But the entire section isn't compressed, just the topmost (floated?) layer of resin gets compromised.
https://www.boatdesign.net/attachments/fiberglass-strength-tests-pdf.148849/
Shows that the compressive strength of cured fiberglass resin is 55-mPa.
For a nominal 3/4" ID washer the stress @ 10,000#f would be ~30-mPa (if the nut doesn't bend the fender washer.) Close enough to be possible considering that, naturally, strength depends on resin/hardener quality/characteristics and the quality of application.
All threads deserve conclusions, so despite the long delay I am following up with my experiences. Hindsight being what it is, I should've listened to you all...
Because of the condition of the hardware, antifreeze I couldn't clean from the joint, and a leak that clearly flowed from the aftmost bolts down to the keel and back up through a screw hole where the bilge pump was (formerly) mounted, I went ahead and had the yard drop the keel. It cost me the whole 2024 season, and may cost me at least some of 2025 too.
- Finding #1: Good news first. The bolts were all still fine (phew!) No signs of "waisting" in spite of how corroded the nuts and washers were.
- Finding #2: oh s***, when they dropped the keel, the lead didn't cleanly separate from the hull and it delaminated some of the keel stub.
- Finding #3: after repairs were completed, but thankfully before the 5200 was finally applied, I got a chance to inspect it myself and discovered the delamination event also caused damage visible from the *inside*. :( The segment behind the mast step has cracks running all the way around , and the segment behind that also has cracks on the foreward end (more than pictured but hard to get a picture of).
Long story short I'm still waiting for the internal fiberglass to be repaired. I'll post back again when I know the extent of the damage (after grinding) and repair job.
That's just outstanding that the bolts were okay after all that. While it cost time and money you absolutely have the assurance that everything is okay below those bolts.
It's amazing how tenacious that bonding agent is, (even after 34 years) that it pulled glass loose rather than just cleanly separating. Mine did the same thing, but fiberglass is repairable so no harm done in the end.
As for those cracks around the bilge, Catalina used a grey gelcoat to fill low spots in and around the bilges, when you sand it you can very clearly distinguish the smell. There is no structural integrity with gelcoat, especially when it's thick and then it is forced to flex....like when you are separating the keel from the stub just an inch or so below it....so it cracks.
I was amazed that on my 88 C-34 that once Catalina installed the Ash into the stub that they then just used one or two layers of glass around the edges, no filleting was done at all and it left an air void below the glass at the turn of the bilge. All I had to do was cut around the edges of the bilge and lift up the keel floor above the wood, no prying effort required. I also realized that the stringers were glassed in along the flat part of the hull, but where it turns into the bilge area there was no glass whatsoever, it was just filled with gelcoat, so that flexing caused the gelcoat filler to crack. It looked bad but it was probably inevitable given the construction method used at the time.
When I glassed everything back in I used epoxy with micro-balloons as a fillet around the edges and glassed the stringers in very securely. I'm confident my bilge is very, very strong now. It should be much stronger than when new and my keel is very securely attached.
Quote from: High Current on October 21, 2024, 09:19:42 AM- Finding #2: oh s***, when they dropped the keel, the lead didn't cleanly separate from the hull and it delaminated some of the keel stub.
There was NO WAY I could have (or would have even tried to) separate my keel from the stub w/o cutting through the entire length of the joint. Even when 1/3 of the joint was deteriorated. (nor would I let the yard where I was at the time even come close to touching my keel to remove it.)
MUNG is tenacious and not easily cut/ground. Gerry Douglas claimed that one could remove the keel nuts, sail the boat, and never lose a keel. I tend to agree with him based on my experience/my keel!!
Ken,
Out of sheer curiosity, how DID you cleanly separate the entire joint, especially in and around the keel bolts when cutting thru the mung????
I worked long and hard to get in around the bolts and all the way thru the joint along its entire length but inevitably I couldn't get all of it so when the keel was lowered it pulled some glass off of the stub, much like what Ben's picture shows.
I'm certainly not looking to do that job ever again but if someone knows something I don't, I'm all ears!!!!
Oh, and I'm in agreement about unbolting the keel and not having any issues....I wouldn't try it but man is that stuff tenacious!!!!!!
Eric
I did not have any issue, as I mentioned I raised the hulk, not lowered the keel. But I just cut thru the mung as closely as I could get.
As I started evenly lifting, it slightly unweighted the keel as it held on. I recall that I was inside when she let go (a deep pitched bang) so I might have been pounding on each bolt nut with a hardwood block and hand sledge.
I dropped my keel five years ago and used 5200 and 4200 around the top of the bolts.have been solid since..
High Current,
The rust is from steel lifting points cast into the lead. Not from salt water reaching the keel bolts.
My keel did not have 100% fill of the mung or whatever was used to glue the keel onto the stub so it came off easy. There was a large void full of water mud and diesel. For the 13 years since I have blocked my boat wrong according to Ron. There is no reoccurring crack or smile anywhere.
Most of the times that there is major damage "down there" it is due to "from above" not from seawater intrusion.
Incorrect blocking doesn't result in major keel bolt/bedding damage.
Been there, done that, got the tee shirt.
11 months later and she's finally back together! 5200 in the seam and sealing the bolts.
Damage to the interior wasn't nearly as bad as it looked once the gelcoat was ground away - mostly only skin deep like Eric described. There was a tabbing failure on the mast step but it might have been old. There was only one other real crack (about 1:00 in the attached picture) that needed fixing.
Launch is scheduled for Monday and there isn't really time to let the 5200 fully cure and then do a proper taping + fairing job, so I'm going to (mostly) follow Dan's approach of painting it and calling it good enough until the fall. Except I'll add a layer of putty and/or barrier coat just to be sure water doesn't attack the glass in the meantime.
Thanks again to all of you for holding my hand through this process. I'm very much looking forward to getting back on the water. Cheers!
Congratulations, looks good! A couple of comments:
1. Don't skimp on the barrier coat. It needs more than one coat.
2. Make sure your keel bolts and washers are NOT coated with gelcoat or paint. This is to prevent rustng due to oxygen starvation.
Had keel dropped 6 years ago used 5200 still smile less.