F32 Keel bolts

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F32 Keel bolts

Postby daletournier » Mon May 02, 2016 8:50 pm

Hi all, I'm hauling out in a couple of months and plan on giving freeform a comprehensive going over in preparation for next year's voyage.
I think I read somewhere (probably here) freedom keel bolts shouldn't be re torqued? The keel bolts were placed in oversized holes and then filled with epoxy? Can anyone enlighten me in regards to the keel bolts and keel hull joint.
Cheers Dale
Freeform
F32
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Re: F32 Keel bolts

Postby Rodent » Tue May 03, 2016 8:15 am

I have just re-cast the shoal draught, fixed lead keel on my F33 (built 1982, T&P, Hull #57). The keel bolts in the bilge, and the external ribbon & resin trim over the hull/keel joint, had always looked a bit suspect, but the impetus to do something came when I found water coming out of the joint, some four years since she had been in the water.

Exploration of the joint showed many voids in the polyester resin with which the keel had been stuck to the hull, which had retained water all that time. It also showed the thickness of the joint as near zero over the middle third, tapering to about 6mm (1/4”) at the tail, and to around 10 mm (3/8”) at the nose.

Looking closely at the bolts I decided to remove the nut from each bolt, one at a time, and found the last bolt sheared off when trying to remove the nut. It was rusted to less than a quarter of good metal, and was cracked into four quadrants.

I removed the keel, which I then found had poor casting at the top, especially near the nose, and after it had stood out in the frost over the winter the nose area began to crack due to frost action on water which had seeped into porous parts of the lead.

Long story short, I decided to build a steel mould and have a local foundry melt the lead and fill the mould. On melting the lead the J-bolts looked shockingly short, and had been bent rather brutally, leading to necking and tearing of the metal on the bend, as well as being of poor grade stainless. The bars had roughly 75mm to 100mm (3” to 4”) embedded in the lead compared to its depth of 450mm (18”) at the tail, 520mm (20”) at its deepest point near the nose. For comparison my new bars have around 400mm (16”) embedment. The J-bolts were set direct into the lead, no epoxy (in fact in an email from Eric Sponberg he said they very rarely used epoxy at T&P)(Eric was also laid back about the tiny embedment - saying it's lasted 30 years, and it is what it is!).

At several stages in the process I had doubts about the need for this work, but having completed it I am thoroughly convinced I have done the right thing, and now have peace of mind. Apart from some minor rippling of the side faces of the new keel, due to distortion of the liner plates by heat and pressure, the outcome is perfect.

My boat and the mould are in the north of England, so it is a long shot if there are any other shoal-draught F33s nearby, but if anyone has such a boat the mould would be re-usable, and I would be happy for someone to have use of it, maybe with a modest contribution towards the cost I had in making it. The mould weighs around 200kg, so is transportable in a reasonably strong trailer.

I have loads of photos and some time-lapse video of the casting process if anyone is interested, I will have to figure out how to share them.

Roy Denton.
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Re: F32 Keel bolts

Postby Rick Simonds » Tue May 03, 2016 8:52 am

That is my understanding, too. The bolts were molded into the keel at an angle, sticking up like a "W". The holes for them in the bottom of the keel stub weren't round, they were oblong slots so the angled bolts could pass into the bilge. The keel was attached, the oblong holes were filled with glass/epoxy goop, then the nuts were put on in the bilge. The angled bolts now can't get back out the holes so, at least in theory, the keel cannot fall off even if the nuts weren't there. The bolts/nuts certainly should be there, be in good condition and tight, but I don't think you would actually be getting the keel any tighter by tightening them to screaming tight.

Source: a conversation with the factory years ago after a particularly hard grounding and also this factoid is in that old F32 newsletter (I think it's here in the documents section somewhere.)
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Re: F32 Keel bolts

Postby daletournier » Wed May 04, 2016 7:12 am

Thanks guys for the info. Freeform has taken a few knocks and the keel is stiil there, always a good thing.
Cheers Dale.
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Re: F32 Keel bolts

Postby Rodent » Thu May 12, 2016 4:44 am

Here are a couple of pics of the old keel bolts. The blue sit mat represents the approximate level of the lead top surface - about 4" outside the lead, 3" inside. The stuff of, if not nightmares, at least sleepless nights!

DSCF4386reduced.JPG
DSCF4386reduced.JPG (199.68 KiB) Viewed 1347 times


DSCF4388reduced.JPG
DSCF4388reduced.JPG (199.15 KiB) Viewed 1347 times
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