Deprecated: Function set_magic_quotes_runtime() is deprecated in /var/www/vhosts/tartan37.com/httpdocs/t37forum/common.php on line 88 Tartan37.com • View topic - Keel Bolt Blues

Tartan37.com

Tartan 37 Owner's Forum - Ride the wind, but look good doing it!
The time is 28 Mar 2024 17:17

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 16 Posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Keel Bolt Blues
PostPosted: 15 Jan 2015 13:33 
Offline
Able Bodied Seaman

Joined: 20 Jul 2014 02:18
Posts: 29
[url]Hello, back again needing advice on keel bolt replacement major, or keel replacement.
My boat is the T38, 1978 model, hull #88.
Most of the original bolts are corroded and 5 or 6 added are not confirmed to have been installed correctly.
It appears that the keel was not removed to install new bolts and we have not been able to find any paperwork on that repair.
The boat is on the hard in Ventura Harbor Boatyard with the keel removed.
Talking to Durokeel out of Mexico and Mars out of Canada.
With possibly a alloy problem with the original bolts, I don't feel good about relying on any of the original and not knowing how new ones were installed I don't have comfort there either.
I haven't figured out how to attach pictures on this site yet.
Any thoughts at this point of development would be appreciated!
Thanks!
Allan


Attachments:
image.jpg
image.jpg [ 80.17 KB | Viewed 0 times ]
 
 Profile Email  
 
 Post subject: Re: Keel Bolt Blues
PostPosted: 15 Jan 2015 16:48 
Offline
Skipper

Joined: 13 Feb 2011 21:19
Posts: 337
Location: Canyon Lake, TX
You are talking to the main players in keel replacement/modification. If the keel is sound, I would pull ALL of the bolts and replace them.

And I was thinking "Go stainless" until I remembered about crevice corrosion. Now I'm not sure. But I would follow the recommendation of Mars on the bolt metallurgy.

_________________
Wayne
Master and Commander of the Sailing Vessel Impetuous
I'm not a complete idiot, some parts are missing.
Subservient to no man except SWMBO
Any day without dock lines is a GOOD day!


 
 Profile Email  
 
 Post subject: Re: Keel Bolt Blues
PostPosted: 15 Jan 2015 17:26 
Offline
Skipper

Joined: 21 Jan 2010 12:57
Posts: 168
If it were my boat (and I'd love to own a deep keel T37 as well as the center-board boat) I believe that I'd be more concerned about the hull where the keel is attached. I should think that the bolts themselves, even corroded, would have much more strength, both in shear and tension, than they'd ever be exposed to. The forces acting on the hull adjacent to the juncture are something, even assuming the boat has never grounded. That being said, I'd look for titanium bolts if I were re- attaching a keel.


 
 Profile Email  
 
 Post subject: Re: Keel Bolt Blues
PostPosted: 19 Jan 2015 10:16 
Offline
Skipper

Joined: 29 Dec 2006 09:38
Posts: 656
I have seen folks go nuts about the little crack that forms between the keel and hull and do all manner of things to try to eliminate it. I think these efforts are mostly in vain. There are enormous forces flexing the long keel as you beat to windward (I have a deep fin keeled T37 as well) I wonder if the PO had someone put some more bolts in there in one of these fruitless attempts to mitigate the crack. If it was my boat, I would look for anything obviously wrong with the bolts and put the keel back on the boat with the proper adhesive sealant, torque the bolts and forget about it. The keel is not going to fall off unless drilling all those holes in the hull stub has weakened the structure---which I seriously doubt. My feeling is that these cracks between the hull and keel are on the same level as "blister prevention" efforts are examples where the "fix" is often more damaging than the original problem. I had some success with my keel crack by putting carbon fiber tape around the joint and fairing it, but there is still a very tiny crack at the front. I would also be thoughtful about rig tension if you are concerned about the crack---the mast compression pushes enormous forces on the front end of the keel on this boat when the rig is very tight. It is possible that the PO overtightened the rig in racing or otherwise and he was chasing that by adding keel bolts. Again, chasing the result rather than the source and probably causing more problems than he was solving.
FWIW


 
 Profile Email  
 
 Post subject: Re: Keel Bolt Blues
PostPosted: 19 Jan 2015 18:52 
Offline
Able Bodied Seaman

Joined: 20 Jul 2014 02:18
Posts: 29
Thank all 3 of you for your replies, they are really helping round out my decision!
I appreciate the two replies on the Hull maybe being more of a focus than the Keel bolts since 5 or 6 extra holes were drilled, although the boatyard is not concerned at all about the hull's integrity.
I am having Alan Andrews, a well respected yacht designer to come over and check out the whole issue and make first hand recommendations on keel and observations of the keelson.
3 of the bolts were definitely corroded, but it seems that was probably due to water trapped around those bolts inside the fiberglass according to Mars.
Which may mean that I can confidently just replace the obvious 3 bolts.
My confidence is growing that such a major overhaul is not necessary the more input I get from experienced sailors and Engineers.


 
 Profile Email  
 
 Post subject: Re: Keel Bolt Blues
PostPosted: 25 Jan 2015 07:18 
Offline
Skipper

Joined: 20 Oct 2006 16:10
Posts: 687
Location: Out of Waukegan, IL
As one who has chased the hairline crack at the connection point, I second the notion that it's in vain. When reinstalling you should have enough caulk around the bolts and the joined surfaces that the crack doesn't mean water getting in or any other damage. I slap on mastik each year and sand it smooth before bottom paint and the crack will reappear only in the leading edge if it's been a light season. If we task her with heavy seas, it goes a bit farther. No matter how you work it, the fin will always have a little flex.

As for the structural issue, I agree there as well. Those originally are J bolts in forged lead. A little corrosion on the exposed part isn't going to allow them to go anywhere. There are only two issues to worry about.
1. Corrosion on the inside
2. Bad replacement bolt.

If there's corrosion inside, you'll get a bulge in the lead. If the boat gets sub-freezing like ours, water that gets in will really bulge it out as it freezes. If there's no outward changes showing and the bolts can't move in their sockets, you're fine.

For bad replacements, if you grind down to bare down the sides, you'll see if any are replacements. The shortcut is to grind the lead away from around the bolt making an empty groove. They place a new bolt there and fill the gap with epoxy. So if you're really curious about the bolts you could grind the top couple inches down to see who's forged and who's puttied in. Then you can slap a couple coats of barrier epoxy (Interlux Interprotect) over the bare stripe and you're ready to bottom paint.

Sidenote: If you do decide on major work for the keel, Mars has a package where they chop a couple feet off the bottom and add fins giving you a shorter draft with about the same ballast. It's a DIY kit, but certainly something they would apply if you were sending it for a reforge. Just in case you're looking for ways to part with your dollars.

_________________
SMMO/First Mate aboard High Flight #299
1981 - Full Keel - Furling Main (A boat for the lazy crew...)


 
 Profile Email  
 
 Post subject: Re: Keel Bolt Blues
PostPosted: 26 Jan 2015 13:11 
Offline
Able Bodied Seaman

Joined: 20 Jul 2014 02:18
Posts: 29
Now we are a little farther down the road of discovery than we were. Last post is also interesting. We, on Thursday of last week ground through the paint and found one of the new bolts had been replaced by a 3" window cut in the side for a nut and washer installation for the new 11/8" bolt.
The cradle the keel is setting in is in the way temporarily for further investigation of the other bolts, but feel reasonably confident they were all replaced in this manner without removing the keel before.
Is this a safe, tried and true method to have had all the bolts replaced by this method, not just 1 or 2, provided the bolts were installed in the right locations?


 
 Profile Email  
 
 Post subject: Re: Keel Bolt Blues
PostPosted: 26 Jan 2015 23:27 
Offline
Skipper

Joined: 29 Dec 2006 09:38
Posts: 656
I am not sure I understand what you are saying or asking. I sure as heck would not mess with the original keel bolts unless I had convincing evidence that they were capable of imminent failure. Personally, I think the installation of the additional bolts sounds Mickey Mouse to me--Generally they do cut a window in the keel, but they install a "J" bolt in strengthened epoxy that wedges against the metal of the keel. I would not worry much about them, however as I seriously wonder if they were needed in the first place. I am judging this without benefit of seeing your window and the arrangement you have, so maybe I am missing something. I have had my Tartan for 24 years and had keel boats for the last 40 and I have rarely heard of keel actually coming loose on any boat (except if you count the aforementioned crack--which does not necessarily indicate a problem) and never on a Tartan without some accident. Is there evidence of a structural repair to the hull behind the keel??? This would indicate some high speed impact that might possibly have caused some damage to the bolts (though I doubt it as it would more likely crack the hull before loosening the bolts) Unless the threads are corroded off, I would put the the thing back on with Thiokol or 5200 and forget about it. By modern standards, the T37 is a montrously overbuilt boat and even the modern flimsy ones don't lose their keels very often. From what you describe you are dealing with an incredibly anxious PO and/or a money grubbing yard. Any gaps in the bolt holes should be filled with epoxy after the keel is set and it is a good idea to keep our bilge as dry as possible. Stainless will corrode, but very slowly without some help. Presence of some rust is not a sign of imminent failure as has been mentioned by others.


 
 Profile Email  
 
 Post subject: Re: Keel Bolt Blues
PostPosted: 27 Jan 2015 01:38 
Offline
Able Bodied Seaman

Joined: 20 Jul 2014 02:18
Posts: 29
There has never been a crack ever mentioned in any of my post.
We recognized corroded original bolts from a survey where the surveyor stuck his knife about 3/8" into the original keel bolts, right above the nuts.
The keel has been removed to see more clearly that the area where the nut is attached to the bolts is the most corroded, nothing really significant below that.
I had Alan Andrews, Naval Architect and yacht designer look at the keel bolts, keel and sump and he recommended that we remove all of the paint off the keel and see if we could find any windows cut into the side of the keel that would be evidence of properly replaced keel bolt procedure. We did so and sure enough they (8 -11/8" newer keel bolts)were installed in that way.
I called Mars and they agreed that was a superior type of bolt replacement and nothing to worry about. Now we are going to improve the sump with layers of fiberglass, and reinstall the keel.
Thanks again for all of you who helped me on this project!


 
 Profile Email  
 
 Post subject: Re: Keel Bolt Blues
PostPosted: 29 Jan 2015 06:44 
Offline
Skipper

Joined: 27 Oct 2006 10:32
Posts: 827
Allan,
Sounds like you will be ready for the spring sailing season!................without worry Very Happy


 
 Profile Email  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 16 Posts ]  Go to page 1, 2  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: Googlebot and 13 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Powered by phpBB © 2002, 2006 phpBB Group