#26
IP: 24.152.132.65
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Quote:
The holding strength of the lags into lead was calculated using 10" lags embedded 7". It turns out 12" lags are less expense than 10" so in practice I'll exceed the calculations by roughly 28%. Further, the calculations were based on pure lead and external keels are typically cast with 5% antimony making the lead even stronger. Calcs exceeded again. The wood shoe was there to spread the load as I described earlier. They weren't the only manufacturer to do it either. The bigger question I think is why is a backing plate not included in the repair? Stainless can be fully encased but I'm not sure there's an advantage to doing so. The ˝" thickness was merely a seat of the pants suggestion by me. If considering aluminum, you're getting into dissimilar metals and galvanic cell territory with the steel keel bolts because there's little reason to expect this area of the boat to be dry.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#27
IP: 174.96.76.34
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Well, the factory repair sheet may contain opportunities for improvement.
OK, so a steel plate. The keel bolts are not stainless steel, so galvanic concerns would arise, would they not? However, if not expected to be dry then steel other than stainless would rust, correct? I seem to recall there is a metals interaction chart - the goal would be to get the metals with the least interaction, correct?
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1978 Catalina 30 |
#28
IP: 108.31.90.116
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Its pictures like these that make me so glad my keel has an internal encapsulated ballast!
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@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
#29
IP: 24.152.132.65
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Correct on all accounts. There is no clear solution with the various metals involved so you have a decision to make after gathering as much information as possible. We have a galvanic series reference in the ABYC/USCG Standards forum category. I reviewed it this morning and it looks like an aluminum plate with careful attention to alloy selection may be your best option.
Regarding Catalina's aging boat repair directives, I recall we've been there before. And as we deal with a factory installed rotting plywood shoe, please remember it has served its purpose for nearly 40 years. I'm not suggesting it but we could put a fresh plywood shoe in there - eliminating the metals issue - and get another 40 years out of it. Where will we be in 40 years? Quote:
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 05-25-2016 at 08:35 AM. |
#30
IP: 107.0.6.242
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Quote:
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#31
IP: 108.79.1.46
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stainless steel requires a thin film of oxidization to protect it. There are lots of different alloys, though. You would need to make sure you got the right one.
Personally I would feel weird about encapsulation. regarding why plywood? cheaper, easier, faster. my plywood was spongy, and the keel barely moved at all. I dug the joint out about 7 years ago, faired it with Kitty Hair and the smile took a few years to re appear.
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john '77 catalina 30 #783 the only way to be sure is to make sure |
#32
IP: 24.152.132.65
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I wouldn't worry too much about the galvanic stuff. Choose your materials with an eye on the nobility scale and you should be good for the rest of your life. For example, nobody utters a peep about steel anchor bolts - or in post 1988 C-30's, stainless steel anchor bolts - embedded in a lead/antimony keel casting. OMG!! GALVANIC CELL!! YOUR KEEL WILL FALL OFF!!!!
Like I said, this inferior arrangement (lead/steel and plywood) has lasted 40 years and counting. Like you and others, I plan on taking preventative measures but really there's no urgency. Yet.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#33
IP: 107.0.6.242
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Nevertheless
All the information I have been able to find suggests strongly that stainless should not be used in an anaerobic, hydroscopic environment. FWIW
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#34
IP: 108.79.1.46
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A reputable yard once told me one way to fix the smile is to" 'glass it in".
In other words, you strip the hull about a foot and a half above and below the joint (on the outside, obviously) and apply a couple layers of 24oz. roving. fair it in and you're done. Thereby partially encapsulating the ballast. I don't see why one could not do the whole keel. It would surely be better fully 'glassed In the end I decided to address the root of all evil - plywood core - and leave my ballast external with a visible joint so I can keep and eye on what's happening down there.
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john '77 catalina 30 #783 the only way to be sure is to make sure |
#35
IP: 174.96.76.34
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John, my plan is to do both inside and outside.
As far as time goes, I was talking to a guy last night who has a Tartan 36 footer of the late 1960s. He said they bought the boat in 1971. He has steel keel bolts and a little smile crack. He said he made a plate out of aluminum to spread the load on the keel stub rather than using washers under the nuts. He worked at Alcoa so the piece of aluminum was free. Said he thought about the galvanic reaction and periodically means to change. He said to date there is no visible issue, so it remains low on the list of stuff. He put the aluminum plate on in 1975. Incidentally, he worked on his topside last year - boat looks new. Beautiful boat.
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1978 Catalina 30 |
#36
IP: 24.152.132.65
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Russell, you might want to ask him what thickness and alloy he used. I'll bet he keeps his bilge dry too eliminating the electrolyte component. There are a number of good reasons to strive for a dry bilge especially for us external keel guys.
I agree with your - and John's and others' - principle: remediate the attachment to the level you're comfortable, seal up the external seam and enjoy the next several decades.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#37
IP: 216.115.121.240
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If you've ever worked wit G10, you'll have confidence in it. But, oh my go$h!
For mine, I just used homemade UHMW washers( ~2") under the new bronze washers for my new bronze keelboats and the same UHMW washers under replacement galvanized where I replace old keel bolts. All bedded in 3M 5200 My wood in keelson was in fine shape though, So I had none of those worries. The other Russ
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Whiskeyjack a '68 Columbia 36 rebuilt A-4 with 2:1 "Since when is napping doing nothing?" |
#38
IP: 24.153.35.7
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lots of work
Hello do not mean to step in on all that fun you have planned. But you have a pretty tough built boat, maybe over built compared to some of the boats of similar vintage that are still doing fine.
I have a similar vintage C30, hull 199. Going with the lag bolts will give you time to do a number of other projects, boat or non boat. I have lag bolts no smile. I have epoxied the inside of the bilge wrapped the base of the mast step in glass. This was done 10 years ago. I just checked it boat went back in the water after painting the topside, all looks good. Don't mean to talk you out of your plans but there maybe easier less expensive fixes that will last longer than you care. |
The Following 3 Users Say Thank You to dew For This Useful Post: | ||
#39
IP: 108.79.1.46
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in my case, all I wanted to do was fix that pesky smile.
Not really a structural problem, more of an annoyance. I was never worried about the keel falling off, and I never had any leakage at the bolts. Also for resale value. If anyone researches C-30's they will soon find out that Catalina stopped the use of plywood in the stub in '83 (I think) and those boats are more desirable because of it, IMO. Hard work? Oh boy. And Dirty. But I'm in construction my whole life, I have the tools and skills, and was able to do the whole job in about 40 hours total including R&R the engine. So now I can say it is fixed to Catalina's specs and I won't have any buyers worrying about "that crack in the hull". I would advise anyone contemplating this job to take an honest assessment of their skill and commitment. It is not for the faint of heart.
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john '77 catalina 30 #783 the only way to be sure is to make sure |
#40
IP: 174.96.76.34
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dew, I concede you have valid points, but I have watched my smile grow over time - it is now the entire length of the keel stub. Bore holes confirm the plywood is wet. So, I want to fix so that I never deal with again.
If I was looking for a rational use of money then I don't think I would have boat at all! Yes, John, dirty hard work. Seems to come with an old boat to me. Bet it is satisfying when done, though?
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1978 Catalina 30 |
#41
IP: 136.2.16.180
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Dead Link
Unfortunately the link that Neil posted appears to be dead. Does anyone have another link or form of the info in that thread that they can share?
http://www.moyermarine.com/forums/showthread.php?t=6226 roughly posts 45 ~ 60 Fred Krabach C30 MKI TR, BS, FK #2239 |
#42
IP: 173.127.118.85
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#43
IP: 24.152.132.140
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I fixed it back in the post.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
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