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-   -   35 morgan keel bolts (http://www.sailnet.com/forums/general-discussion-sailing-related/77004-35-morgan-keel-bolts.html)

dean burney 07-31-2011 12:42 PM

35 morgan keel bolts
 
anyone ever tried to replace the keel bolts on a thirty five morgan i wonder if they are poured into the keel or could they be other wise removed

SloopJonB 07-31-2011 01:29 PM

Quote:

Originally Posted by dean burney (Post 756795)
anyone ever tried to replace the keel bolts on a thirty five morgan i wonder if they are poured into the keel or could they be other wise removed

If the keel is lead, they are in place when the keel is poured. If it's iron they are studs threaded into drilled & tapped holes. In some cases like the Thunderbird, the iron keel has a wide flange where it meets the hull and the "bolts" are actually large flathead machine screws countersunk into the bottom of the sides of the flange with the threaded portion sticking up into the bilge where nuts & washers are put on.

The bolts in a lead keel are normally bent into an L before pouring and are not removable. In that case you have two choices - cast a new keel with new bolts or drill down into the keel and cut a window into the bottom of the hole from the side of the keel so you can put nuts & washers on the bottom of the new keel bolt. Lead is too soft to drill & tap as you would with iron.

erickbou 07-31-2011 10:48 PM

I am researching to also fix a crack in my hull to keel joint, I have a 1978 Hunter 33 with lead keel. I found this article very helpfull

Projects: Below Deck: Replacing Keel Bolts | MadMariner.com

I am hoping in my case that I can get away with the "heavy sleeve" method.

Good luck.

SloopJonB 07-31-2011 11:10 PM

Quote:

Originally Posted by erickbou (Post 757018)
I am researching to also fix a crack in my hull to keel joint, I have a 1978 Hunter 33 with lead keel. I found this article very helpfull

Projects: Below Deck: Replacing Keel Bolts | MadMariner.com

I am hoping in my case that I can get away with the "heavy sleeve" method.

Good luck.

It sounds pretty mickey mouse for something as heavy as the keel on a 33 footer. You might try finding a foundry near you that can melt down & recast your keel with new studs. They can make a form by pouring concrete around your keel then pulling it out, melting it down and pouring it back into the concrete mould. If you do this, be sure to make a template of your keel bolts beforehand then when they are pouring, the new bolts can be held in place by the template and will then fit the original holes in your hull.

erickbou 07-31-2011 11:34 PM

Don't dismiss this so rapidly. You can easily find SS 316 theaded coupling with design loads of over 1100lbs each. In my case the keel is 4100lbs and has 6 or 7 bolts, plus the epoxy filling in the keel to hull joint, plus the fiberglass seal on the outside. Both of these reducing the stress on the bolts. I think that it can be a simple and elegant solution if implemented correctly.

For me it remains a viable option if the original bolt is not corroded at the base.

SloopJonB 08-02-2011 03:46 AM

Quote:

Originally Posted by erickbou (Post 757034)
Don't dismiss this so rapidly. You can easily find SS 316 theaded coupling with design loads of over 1100lbs each. In my case the keel is 4100lbs and has 6 or 7 bolts, plus the epoxy filling in the keel to hull joint, plus the fiberglass seal on the outside. Both of these reducing the stress on the bolts. I think that it can be a simple and elegant solution if implemented correctly.

For me it remains a viable option if the original bolt is not corroded at the base.

At 1100 lbs strength (is that max tensile or yield strength?) that would give you a total strength of either 6600 or 7700 lbs, depending on 6 or 7 bolts total. That is less than 2 to 1 safety margin at best and only 1.5 to 1 on the low end.

For comparison, when I redid the keel fastenings on my 43, I thought the 10 X 3/4" bolts looked a little skimpy so I did some research to reassure myself - even though the 1/2 corroded originals held it on with no leaks.

Here are the numbers for my boat;

- Keel weighs 10,200 lbs
- Static load on each bolt - 1020 lbs
- Total tensile strength of 10 bolts - 289,000 lbs- a 28 to 1 safety margin
- Yield strength - 136,000 lbs - a 13 to 1 safety margin
- Max loading at 90 degrees of heel (knockdown) 3 times the keel weight or 30,000 lbs in this case. Dynamic loadings are not calculable as far as I know but are well in excess of the highest of these numbers - falling off a wave for example.

These figures are FAR in excess of the safety margins provided by your figures and they are for a set of bolts that looked skimpy to my eye and are smaller than would be spec'd for a comparable boat now - I've seen lots of 35 footers with 1" bolts.

I'd strongly recommend you do some more research before going out in deep water with your life depending on those couplings.

eherlihy 08-02-2011 08:50 AM

I've been down the keel bolt replacement road... I would not "sleeve" the bolts, as the Mad Mariner article suggests, as this will only mask the problem and likely contribute to crevice corrosion further down the bolt.

Mars Keel has a write up of the correct procedure. Look here; MarsKeel Technology Keel Bolt Replacement

It should cost under $500/bolt for a proper repair

deniseO30 08-02-2011 09:52 AM

All this keel bolt talk has me wondering now. It almost seems that it's better to seek out a iron keeled boat since it's so expensive to do them in lead.

Truthfully, to burn or drill out in lead and put in cross doweled bolts or half round washers and re-lead is not within DIY territory? I hear risk mentioned, but no matter how well a professional shop would do the work would they not have lots of legal disclaimers in their agreement with you? And in the end.. (err bottom) it's the keel stub/sole/shoe that is almost always the area that fails?


Jus wonnering :rolleyes:

deniseO30 08-02-2011 10:03 AM

Oh, and has anyone actually EVER been able to remove a bolt out of an iron keel? If so, is there ANY way to insure they can be removed in the future?

Jus saying

hurricanehole 08-02-2011 10:08 AM

Hey Dean-what has happened to make you want to redo the keel bolts? I have a 70's Morgan 35. The keel is lead but the bilge has rusty metal on top that the bolts go through on mine. Great boat but I hope your below waterline glass did better than mine as I had to almost rebuild to get rid of the blisters.


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