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Keel Bolts

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dolivaw
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USA
109 Posts

Response Posted - 05/08/2012 : 11:53:14

Upon further reflection...

After hauling the boat and examining the keel Ben recommended leaving the keel bolts alone. The wobble is very slight and there's no damage to the glass or the seam between the hull and keel. Since the only damage to the bolts appears to be in the bilge we'll clean them up and coat them to prevent further rusting. After that, we'll re-inspect at every haulout.

Anyone know what a replacement keel would cost? I imagine it's not realistic, but I'd love to just replace the keel and have the keel stub core ripped out and replaced with glass.

Edited by - on

Sloop Smitten
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1181 Posts

Response Posted - 05/08/2012 : 12:50:46

JMHO but you would be better served to buy another boat. Replacing a fin keel on a 1981 C25 would be a lot of money and frustration. By the time you were done you could have used the money to buy a newer or better boat not requiring that headache. I like you idea of sealing off the studs and maintaining vigilance. No one on this forum has ever mentioned having a fin keel failure. My 78 C25 studs were just piles of rust when I added sistered bolts but never indicated any type of ultimate failure. No leaks, no wobble.

Edited by - on

dolivaw
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Response Posted - 05/08/2012 : 14:16:30

I'm sure you're right, Joe... And someday in the not too distant future we do hope to go bigger.

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Stinkpotter
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Djibouti
9081 Posts

Response Posted - 05/08/2012 : 15:04:56

I'm not confident that replacing the wood core with glass would be the solution. If it were that easy, Catalina would have built it that way. Wood has some structural strength properties that fiberglass doesn't share--my current boat was built in 2007 with pressure-treated fir stringers in the hull, encapsulated with fiberglass. Fir was used for a reason--it's sort of old-school, but it's part of the marine architecture of the boat. There might be a good composite core (like Nida) for the purpose, but that should be determined by a marine architect--perhaps at Catalina Yachts.

The stresses on the joint connecting that 1900# hunk of cast iron and your hull are considerable. An inadequate keel-hull joint killed a Texas A&M student in the Gulf of Mexico when the keel fell off a racing sailboat. I haven't heard of them falling off C-25s yet, but more than a few people have added bolts to various older sailboats including C-25s.

As for damage, could you see whether all of the keel bolts were still solid below the surface--none cracked, broken or disengaged from the iron? It seems unlikely that you could. A "little wobble" could work on them until one of those things happens, and could allow moisture into the joint.

Your hunk of cast iron is fine. The stub is apparently fine. The condition of the bolts is indeterminable, but we know they've been rusting. I'd seriously consider sistering in some all-thread stainless studs. (Catalina Direct sells a kit.) I'd make sure the installation protects the wood core from moisture from the inside as well as the outside--e.g., maybe some penetrating epoxy in the new holes.

I also would not want to sell (or give) a boat to somebody else because I wondered whether the keel was about to fall off.

Edited by - on

JimGo
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Response Posted - 05/08/2012 : 18:06:39

OK Ron, I have to ask this, and sorry for the thread highjack - is your username a reference to the robot in iRobot?

Edited by - on

OJ
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Response Posted - 05/08/2012 : 18:14:00

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 . . . I'm not confident that replacing the wood core with glass would be the solution. If it were that easy, Catalina would have built it that way. Wood has some structural strength properties that fiberglass doesn't share . . .
<hr height="1" noshade id="quote"></blockquote id="quote">

A tree that does not bend - breaks.

Edited by - OJ on 05/08/2012 18:15:23

OJ
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Response Posted - 05/08/2012 : 18:19:08

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 . . . As for damage, could you see whether all of the keel bolts were still solid below the surface--none cracked, broken or disengaged from the iron? . . . Your hunk of cast iron is fine. The stub is apparently fine. The condition of the bolts is indeterminable, but we know they've been rusting . . .
<hr height="1" noshade id="quote"></blockquote id="quote">

Dave is spot-on:

http://www.pbase.com/mainecruising/image/92985071

http://www.pbase.com/mainecruising/image/97591698

http://www.pbase.com/mainecruising/image/114717066

http://www.pbase.com/mainecruising/image/118624441

Edited by - OJ on 05/08/2012 18:22:35

dlucier
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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 05/08/2012 : 19:18:20

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 I'm not confident that replacing the wood core with glass would be the solution. If it were that easy, Catalina would have built it that way.<hr height="1" noshade id="quote"></blockquote id="quote">

It appears replacing the wood core with glass is what Catalina recommends. Who knows, maybe they're now making boats this way as well.

http://www.blumhorst.com/catalina27/images/keel_factory_drawings/keel_stub_wood_procedure_from_catalina.gif

Edited by - on

Sloop Smitten
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1181 Posts

Response Posted - 05/09/2012 : 07:55:32

Ron,
Just curious but how did you determine the keel has a wobble? At 1900 lbs I think it would take a sizable force to even "wobble" it. The bolts that OJ shows in his picture look like stainless steel that has disintegrated due to a dissimilar material issue. The cast iron studs and nuts tend to disintegrate into a pile of rust which can be somewhat stabilized by coating the accessible surfaces with a rust stabilizer which chemically bonds to the rust. Since oxidation of iron requires oxygen it could be the studs remaining in the sole/keel have more material left than the visible portion. But nobody knows for sure since the studs are virtually impossible to remove..

Edited by - on

dolivaw
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Response Posted - 05/09/2012 : 10:21:30

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by dlucier
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 I'm not confident that replacing the wood core with glass would be the solution. If it were that easy, Catalina would have built it that way.<hr height="1" noshade id="quote"></blockquote id="quote">

It appears replacing the wood core with glass is what Catalina recommends. Who knows, maybe they're now making boats this way as well.

http://www.blumhorst.com/catalina27/images/keel_factory_drawings/keel_stub_wood_procedure_from_catalina.gif
<hr height="1" noshade id="quote"></blockquote id="quote">

It's my understanding that Catalina stopped using a wood core in the C25's in the late '80s, or maybe early 90's, and recommended replacing the wood core with glass on earlier models that had wet cores.

Edited by - on

dolivaw
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Response Posted - 05/09/2012 : 11:39:06

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by JimGo
 OK Ron, I have to ask this, and sorry for the thread highjack - is your username a reference to the robot in iRobot?
<hr height="1" noshade id="quote"></blockquote id="quote">

Well, no, but very close. =)

The robot in "I, Robot" was named Sonny. Dolivaw actually refers to "R Daneel Olivaw", who was the robot in Asimov's Robots, Empire and Foundation trilogies. (Actually, only in the Robots trilogy, but he was in the books that bridged the three storylines.) The "I, Robot" movie was based on a short story of Asimov's of the same name.

Edited by - on

dolivaw
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Response Posted - 05/09/2012 : 11:45:07

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by OJ
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 . . . As for damage, could you see whether all of the keel bolts were still solid below the surface--none cracked, broken or disengaged from the iron? . . . Your hunk of cast iron is fine. The stub is apparently fine. The condition of the bolts is indeterminable, but we know they've been rusting . . .
<hr height="1" noshade id="quote"></blockquote id="quote">

Dave is spot-on:

http://www.pbase.com/mainecruising/image/92985071

http://www.pbase.com/mainecruising/image/97591698

http://www.pbase.com/mainecruising/image/114717066

http://www.pbase.com/mainecruising/image/118624441

<hr height="1" noshade id="quote"></blockquote id="quote">

From what we can see there's no evidence of 'crevice corrosion' on the keel bolts. The seam between the keel and keel stub is intact and there's no cracking in the fiberglass around the seam. The core samples he took from the bilge through the stub and into the keel were completely dry. It doesn't appear that there's ever been any water between the stub and keel to corrode the bolts. The only indication of rust is on the nuts and bold-ends in the bilge.

Edited by - on

dolivaw
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109 Posts

Response Posted - 05/09/2012 : 11:56:10

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Sloop Smitten
 Ron,
Just curious but how did you determine the keel has a wobble? At 1900 lbs I think it would take a sizable force to even "wobble" it. The bolts that OJ shows in his picture look like stainless steel that has disintegrated due to a dissimilar material issue. The cast iron studs and nuts tend to disintegrate into a pile of rust which can be somewhat stabilized by coating the accessible surfaces with a rust stabilizer which chemically bonds to the rust. Since oxidation of iron requires oxygen it could be the studs remaining in the sole/keel have more material left than the visible portion. But nobody knows for sure since the studs are virtually impossible to remove..
<hr height="1" noshade id="quote"></blockquote id="quote">

We noticed the wobble when they had the boat on the lift for a quickhaul last September. It is very minor, but noticeable when they moved the lift with the boat in the cradle. That yard suggested I tighten the bolts. The new yard is telling me that a little flexing of the glass around the keel is normal when the boat heels and when it's on the lift.

Since we can't actually examine the condition of the bolts between the keel and the stud, and since all other evidence implies there isn't a problem with the bolts, he's recommending that we just keep a close eye on the keel for now. If the wobble gets worse, or we get a Catalina smile due to seam separation, or we see any water in the bilge from the keel, then we'll sister in new bolts. Some of the yards I've talked to have also suggested glassing the keel stub and adding backing plates.

Edited by - on

Stinkpotter
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Djibouti
9081 Posts

Response Posted - 05/09/2012 : 21:18:02

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by dolivaw
 It's my understanding that Catalina stopped using a wood core in the C25's in the late '80s, or maybe early 90's, and recommended replacing the wood core with glass on earlier models that had wet cores.<hr height="1" noshade id="quote"></blockquote id="quote">Fine--if that's what they recommend. I would carefully investigate the appropriate laminations, perhaps including a composite core or backing material to spread the load from the bolts. This is a very high-stress area, as indicated by the "wobble" of that 1900# lever.

Edited by - on

CarbonSink62
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Response Posted - 05/10/2012 : 10:29:57

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 If the '81 FK is cast iron, which I believe it is (not steel)... <hr height="1" noshade id="quote"></blockquote id="quote">

ok, so it is iron, not steel. What's a little Carbon among friends? (do you see what I did there?)

Edited by - on

dolivaw
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Response Posted - 05/10/2012 : 11:21:31

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by CarbonSink62
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 If the '81 FK is cast iron, which I believe it is (not steel)... <hr height="1" noshade id="quote"></blockquote id="quote">

ok, so it is iron, not steel. What's a little Carbon among friends? (do you see what I did there?)

<hr height="1" noshade id="quote"></blockquote id="quote">

:)

Edited by - on

JimGo
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Response Posted - 05/10/2012 : 11:53:07

Thanks! I knew it was Asimov; I forgot that it was from the series. I read most of those one summer MANY years ago (literally over half my life ago) when I was in my late teens, sitting on my parents' power boat. Great reading!

Edited by - on

pastmember
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Response Posted - 05/10/2012 : 15:50:54

The Foundation trilogy won the Hugo to beat The lord of the Rings. Remember my '89 was named FellowShip

Edited by - pastmember on 05/10/2012 16:24:58

dolivaw
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Response Posted - 05/11/2012 : 00:31:29

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by JimGo
 Thanks! I knew it was Asimov; I forgot that it was from the series. I read most of those one summer MANY years ago (literally over half my life ago) when I was in my late teens, sitting on my parents' power boat. Great reading!
<hr height="1" noshade id="quote"></blockquote id="quote">

Decades later and he's still my favorite author, and I've been through a few. =)

Edited by - on

dolivaw
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Response Posted - 05/11/2012 : 00:44:29

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by pastmember
 The Foundation trilogy won the Hugo to beat The lord of the Rings. Remember my '89 was named FellowShip
<hr height="1" noshade id="quote"></blockquote id="quote">

Tolkien, Asimov, Herbert and Heinlein were all obsessions of mine for many years. And I need a new name for my boat too. Hmm...

Edited by - on

JimGo
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Response Posted - 05/11/2012 : 06:02:30

Ron, if it's your first boat, Foundation would be kind of neat.

Edited by - on

Tomas Kruska
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Czech Republic
522 Posts

Response Posted - 06/29/2012 : 03:00:19

I would like to replace my keel nuts and on the iron cast fin keel.
Does anybody knows what is the diameter and thread type (UNC, UNF or Whitworth) of those screw-rods?

Problem is it's not metric and I will have quite issue getting these nuts here.

My keel bolts are very rust so I'm not sure I would be able to unscrew them but if I will brake that nuts, I'm still hoping that the threads will be somehow ok.

Anybody tried this?

Edited by - Tomas Kruska on 06/29/2012 03:43:21

skybird
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Response Posted - 06/29/2012 : 09:44:25

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by dolivaw
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by pastmember
 The Foundation trilogy won the Hugo to beat The lord of the Rings. Remember my '89 was named FellowShip
<hr height="1" noshade id="quote"></blockquote id="quote">

Tolkien, Asimov, Herbert and Heinlein were all obsessions of mine for many years. And I need a new name for my boat too. Hmm...
<hr height="1" noshade id="quote"></blockquote id="quote">

I have had several Gandalfs through the years, both power and sail, thanks to Mr Tolkien

Edited by - on

diySailor
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Response Posted - 06/29/2012 : 19:30:35

Tomas, I don't know if my threaded rods are original but they are 5/8 inch (.625") diameter X 11 threads per inch and use a standard hex nut with the same thread (class 2A). I am in the middle of replacing my keel bolts too. A previous owner used stainless steel nuts on the plain carbon steel threaded rods. Luckily the rod rusted so tight to the nut that I was able to completely back out the first two threaded rods (still have to try the others). The rod's diameter above the nut was corroded down to .25 inches. The threads on the plain steel rod that were in the casting were near perfect and after I scoped the threads in the casting they appeared OK as well (difficult to tell for sure). The threads above the casting were somewhat corroded and so I am routing out the rotted wood and will refill with penetrating thickened epoxy.

Edited by - on

Tomas Kruska
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Czech Republic
522 Posts

Response Posted - 06/30/2012 : 04:13:59

Thank you very much Roger, I will check mine and let you all know.

Just one additional question, how log are those rods you were able to remove?

I was also thinking about replacing the nuts and rods with stainless steel ones but then I've read that its not a good idea, because they are galvanically different so the threads in the keel would be eaten by SS rod. That's why they are not SS from factory.

Maybe the zinc coated would be ok.

I think they just need some checking an replacing them periodically after a 10 years or so.

Edited by - on

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