Lead keel experience anyone ??

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slipknot

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I may need to change the keel bolts on a Feeling 1090. which has a lead keel.

I cannot find out the spec of the bolts used.

I understand that there may be two types of bolt used.

Firstly the normal threaded stud going into a captive nut in the keel, which can be unscrewed from the keel and removed/replaced.

The other type is where the threaded stud is bent into a 'J' shape and positioned when the lead keel is poured. Excuse the pun, but in this case, I think it is you that is screwed!

Anyone have any experience of keel bolts in lead keels, how can you tell which option has been used, Feeling 1090 keels in particular.........

Any advice aprreciated
 
I have a lead keel but not on a Feeling. I needed to replace the backing plates. It was hard enough to get the nuts off the studs. I did not get the impression that removing the studs from the keel would be at all easy. I concluded that they were probably cast in place.
 
Having a lead keel, and nuts threaded onto studs I have always assumed that the studs are cast into the keel as J-Bolts.

The alternative of a threaded studs "screwed" into captive thread of some sort, then driving a nut down onto the stud seems wrong. Why not simply screw down an appropriately sized bolt down into the keel?

I am sure that a suitably qualified marine architect / engineer will be along and explain the issues at hand.

Regards,
Jeff.
 
I guess one reason would be apparent if you have ever owned a car whose wheels are attached with bolts, rather than nuts on studs. It was a painful job to get the wheel aligned with the hub and I guess it would be much worse if the 'wheel' weighed several tons and was being manouevred with a crane.

Apart from that, the preferred method of very many similar technologies is the same, studs screwed into the static part (engine blocks, large pumps and compressors, pipeline valves, etc). The stud generally remains in place and the nut is removable. Not only for the reasons given above, but for reduced friction when making up the joint, and also to reduce damage in the major component. A stripped thread between a nut and stud is easily rectified, whereas in a tapped hole in a keel it is considerably more of a problem.
 
The tapped thread tolerance can be tighter for the studs than the nuts will be, the stud can often be jammed/forced into the depth of the thrwead, and in any case it's a longer thread depth, and for all these reasons the stud should stay in place when nuts are screwed/unscrewed.

To undo a stud needs two nuts locked to each other and unscrew the lower one with a decent wrench and perhaps an extension tube.
 
I knew that there would be a sound explanation. I shall not try "pulling" one of my studs - they are far too large to take on without all of the appropriate tooling. The nuts require a 46mm socket.

Cheers,
Jeff.
 
I recently removed my lead keel, the boat was built in 1971.

The 6 keel studs are "J" form, cast less than 25cm into the lead. (I know this because I cut the keel in two horizontally, 25cm from the top)

I last removed the nuts in about 1991 to lower the keel slightly to renew the seal to the hull. Some of the nuts were damaged during removal.

I had difficulty finding new nuts (5/8 UNF) in Mallorca, and a couple of those I refitted were stainless steel. I used 2 nuts, locked on each stud.

When I removed the nuts I found there was some galvanic corrosion of the stud threads inside the stainless nuts, as stainless steels are more noble than steel. I should have realised that! This was not terminal, just the very top of the threads were damaged. As the stainless nuts were above the steel ones, the lower part of the threads was OK. I decided there was plenty of thread left to hold the keel for another 20 years or so.

I cleaned up the threads, replaced all the nuts with new steel ones, and also screwed a couple of propellor hub anodes onto the protruding ends of the studs.

If studs cast into a lead keel require replacement, the only option really is to drill right through the keel and fit long bolts with large washers, or better, a steel plate under their heads at the bottom of the keel. If threads for studs were simply tapped into the lead there is a high possibility that these would be gradually stretched by the keel working, and eventually the studs could pull out.
 
Thanks Challenger 32, very useful info.

I understand that you lowered the keel in 91 and replaced the keel bolt nuts and re sealed the joint.

Why did you 'cut the keel in two horizontally, 25cm from the top' and when did you do that? Just curious.....
 
slipknot.

Sorry I missed your post and question, I must have been away sailing - or more likely working on the boat!

I cut 25cm off the keel to reduce draught, as the boat is now a canal boat, mast also removed. With the original draught of about 1m55 I couldn't even get into the Canal at Port la Nouvelle. At least we now use her more, as sailing was getting too much like hard work for us.

My calculations were a little awry, as due to the loss of around 1800 lbs of ballast, plus the mast, spars and rigging, the boat now floats about 15cm higher, reducing the draught to about 1m10. Even so, we still touch bottom occasionally, and have to look carefully for places to get close in to the bank when tying up.

The bottom part of the keel is still sitting in my garage. Luckily I have a 5 ton pallet shifter to move it around, which I bought to shift it from under the boat and to manoeuver the reshaped keel back into position. This being cheaper than paying for travelift operations.

I may recast it into suitably shaped ingots to fit it all into the deep bilge above the keel. This should raise the original CG of the keel by about 25cm, restoring enough stability that with the mast in a tabernacle we'd be able to sail now and again.

She rolled quite heavily during the ten mile sea trip to Port la Nouvelle in a beam sea with the mast on deck, a bit uncomfortable, but it didn't feel at all dangerous.

Actually it was - I had only the engine to rely on, and the flex disc coupling to the gearbox destroyed itself. Luckily we were in the canal by then and just drifted to the bank, where we spent a week relaxing in the sun while I made repairs in my own good time.

Richard
 
feeling 1090 bolts

Hi Slipknot, the nuts on my bolts have sadly become corroded, a recently acquired Feeling 1090 - 1989 model.

Saltwater dripped off my water pump, pump all renewed now however the keel nuts are rusty!

The corroded nuts are not stainless nor were the washers.
The bolts are stainless.

Im having similar trouble as you had accessing technical data.

I want to replace nuts and washers with stainless.

the bolts on my keel are three at 20mil dia, and one at 13mil diameter.
How much torque did you decide to put on your keel bolts.

There may be another bolt under the saloon table - i have yet to look!

I have been advised to use 316 grade stainless nuts by a boatyard. What did you use and are there any other options.

Regards,

Conor
 
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