I've just had a look at my lifting keel. A few questions:

ProDave

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Now that most of my jobs are done on the boat, I thought I would satisfy my curiosity and have a look at my lifting keel mechanism, so I took the table off to expose the top of the keel box to have a look. See picture.

When I bought the boat I was told it was a lead keel. Well it may be, but it looks to me more like steel or cast iron. But hard to tell, as the whole thing is encapsulated in GRP so the only bit of bare metal exposed is the tab the lifting wire shackles onto, and that's definitely steel or iron.

I can't lower the keel at present on the trailer, so with the keel up, as in the photo I can't inspect the pivot, but this summer I'll modify the trailer to allow the keel to lower on the trailer.

The way the keel on this boat works is there's a screw that you wind with a windlass handle (inside the black tube at the bottom of the photo) the "nut" that winds along this pays out the steel wire, that goes round 2 pulleys, into the end of the keel box, over a roller and onto the keel.

There's a rope also tied to the shackle. I can't immediately see it's function other than a tell tale. (I was wrong on another thread, the rope just does what the steel wire does, I thought it was the opposite) I see no point in retaining this. It's not strong enough as an auxilliary lifting cord, and you can confirm the keel is lowering okay just by looking at the steel rope (if the steel rope goes slack, the keel is stuck)

Having seen the keel mechanism, I have just 2 concerns:

Firstly, the tab the wire shackles to is somewhat coroded. I don't think it's in imminent danger of failure, but I want to treat it to stop further corrosion. So I'm planning to wire brush it clean, treat with some car type rust inhibitor, then a thick coat of paint. When re assembling, a liberal coating of something to keep moisture out, perhaps grease or Vaseline?

My only other concern is the roller in the centre of the keel box. The wire rope had jumped off this roller, and for some time has been rolling instead on one of the spacer blocks that look to be made of tufnell or similar. You will see that when fully raised the crimp that makes the end of the wire rope rides up onto the roller. Not a very clever design. If I can unbolt the fixings for this roller, I intend to make two metal cheek blocks to fit immediately either side of the roller to try and keep the wire rope on the roller.

I'm not too concerned at the crimp riding onto the roller. When afloat, I leave the keel ever so slightly down, so the crimp won't ride up onto the roller then, It will only be once a year to load the boat onto the trailer that I have to wind the keel all the way up and then the crimp will ride up onto the roller.

Any other comments?

As I said earlier, the whole keel is encapsulated in GRP and there's a hollow GRP box cast into the top of the keel that you can see on the left in the photo, it looks to me like that's just to locate the keel snugly in the keel box.
 
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Seajet

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I'm probably beind dense as usual, but what's your actual worry / question ?

Has the wire bit into the roller ?

To me at least it's a bit hard to make out the operation of the keel from the photo & description...

One thing did strike me, as you say, a lead lifting keel is unlikely, and if it's encapsulated steel I'd want to check for corrosion, and inhibit it; may be a case of drilling a drain hole and seeing if water comes out ?
 

ProDave

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Hi

I had a look at the keel today really out of curiosity, not because I thought anything was wrong, besides, I just like to know how things work, rather than just knowing there's a keel inside that box but I don't even know what it looked like or how it operates.

My biggest concern was the corosion of the exposed tang that the wire rope shackles to, and if my plan to just treat the rust and paint it was okay. Bear in mind this is a 30 year old boat, so that's 30 years of rust. At that rate is should last me out. I also notice the hole that the shackle bolts into in this tang has elongated somewhat, but again at that rate of wear, it's got a lot of life in it yet.

I'n not concerned at corosion of the keel within. If it was rusting, rusty metal expands, and there would be some sign of the encapsulation expanding, cracking etc. It all looks fine to me so I'm not worried on that score.

The wire rope hasn't bitten into the roller, but as I say, when I opened the keel box, the wire rope was not on the roller, but had jumped off and was rolling instead on one of the tufnell spacer tubes, and it has bitten into that, hence my plan to make some cheek plates to try and keep the wire on the roller.

To try and explain what you are seeing in the picture. It's taken from directly overhead looking into the keel box. The left of the picture is the front of the keel box, and the right of the picture is the back of the keel box.

So the T shaped thing at the right is the actual keel, with the top of the T (left in this picture) being the bit that rests on the bottom of the boat when the keel is down. In other words that's the aft end of the keel. The front end of the keel pivots close to the floor at the front of the keel box, right down in the dark bit at the left of the picture, but I can't see the actual pivot so don't know what it pivots on.

My only other question was that bit of rope. I really can't see why it's there. I plan to remove it, unless someone gives me a good reason why it's there and why I shouldn't. It just exits the keel box next to the wire rope and hangs down onto the floor of the boat.
 

sarabande

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is the rope a sort of safety device in case the wire parts ? You have at least a sort of means to lift the keel in that case.
 

ProDave

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is the rope a sort of safety device in case the wire parts ? You have at least a sort of means to lift the keel in that case.

Possibly, but I doubt it's strong enough. According to the spec of the boat, the ballast is 525lbs. Whether that is all in the keel, or if there is fixed ballast as well I don't know.

But even if the rope was strong enough, you wouldn't be able to get the purchase to just pull it from the end of the keel box.

So if the wire rope ever did break, it would be a case of remove the top of the keel box and reach down to fix an emergency lifting line, and lift directly up.

To prevent that of course an annual inspection seems wise, and at the first sign of doubt, replace the stainless steel lifting wire.
 

Lakesailor

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I would imagine it most unlikely that the whole 525lbs is the keel. I broke a 19ft micro cup racer and the solid lead keel and bulb weighed 157 kgs.
On my 17ft Seahawk there is 300lbs of concrete and steel either side of the keel box, in the stub keel. The keel itself is only 70lbs. But it is just a blade to reduce leeway.

keel2.jpg


keel6.jpg


keelweight.jpg
 

William_H

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Lifting Keel

I think you are right about the rope being of no use. In the worst case when the keel is nearly up you are pulling with an arm of about 30cms to raise a keel typically 1metre with CofG of .5 metre from pivot. So load on wire is going to be 50/30 X 250Kg or about 400Kg. Of course my math may be wrong but still a fair load.
Regarding the top roller for the wire. With the keel in the near up position the pull of the wire should be such that there is very little load on the roller. Indeed if the roller were a little lower the wire would lift off the roller. (this depends on the height of the wire pull at the front. In either case the swage mounting the roller will not put much pressure on the roller.
You may be able to remove the roller with keel up. A wider sheave with deeper groove or as you suggest metal side plates would help keep the wire on the sheave.

As you suggest the box structure at the front /top of the keel is to make it fit tightly in the keel box so stop any side movement or vibration.

If your trailer has a lot of rollers down the middle below the keel it may be possible to remove the rollers to enable keel to be lowered a bit. You may find however that there are cross members and an axle in the way. Mine is a vertically lifting/ dropping keel so it is not so long front to back. I push the boat backwards on the trailer until the keel is over a clear area of the trailer then it will drop till it hits the ground. I can jack the trailer or put it on ramps to allow even more of the keel to drop down. I can a/f paint the bottom half then finish the top half inside the cabin. Only trouble is the paint tends to be scraped off when it is dropped. I keep it down when in the water. Anyway my ideas are not likely to be applicable to a swing keel. PS my keel is 100Kg of lead and wood in a f/g skin with more ballast under floor.
good luck olewill
 
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The whole keel would never be lead - its far too soft to be used for the sort of pivoting arrangement you have. But the bottom bit could still be lead

That shackle fitting looks good to me for the number of years used. If you paint it and have any galvanic action then that action will be concentrated in the bit where there is no paint film - the pivot itself. So if you do paint I would be inclined to fit a small anode nearby.
 

ProDave

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I've finished my keel overhaul today. Thanks for al the help and suggestions.

Firstly the rust was removed, rust treated, two coats of anti rust primer then finished off with car body underseal.

I couldn't undo the bar on which the roller rotates. It's just a bit of round bar with a tapped hole in each end, but of course as soon as you undo one bolt, the bar just rotates, so no way to undo the other bolt. So instead (see picture) I made two guides of flat metal bent to an L shape each bolted to the top lip of the keel box. This should ensure the wire rope can't jump off the roller.

On close inspection, I found 1 single strand of the wire rope had broken in the end loop at the keel end. Now if this was my mast rigging, I would be replacing it. I might replace this wire rope soon in view of that, but for now, I have reversed it, so the end with the single broken strand is now outside the keel box where I can keep an eye on it for further problems. That end was not fitted with a thimble (perhaps the resulting sharp bend was the reason for the broken strand?) , so I managed to fit one in. At the keel end, I replaced the shackle for one the same size but slightly shorter to reduce the amount the crimp rides up onto the roller when fully raised.

That wasn't the end of my work though. I found the two rollers that the wire rope passes round before entering the keel box were both siezed. Due to limited access I had to remove the whole wind up mechanism from the keel box and take it to the bench to have enough room to get a spanner on, and where I could get to it with a hammer. It's now all freed up and working and well lubricated.

I'm glad now I had a look at the keel. When we bought the boat the broker told us the lifting keel had been overhauled in 2009. I wonder how many people would have believed that and assumed all was well? IMO either someone was telling porkies, or if the previous owner did pay to have the keel serviced, he was ripped off, because there's no way it had a proper overhaul that recently.

I think this shows why all lifting keels should be inspected and serviced regularly, and if you have just bought a boat and been told the keel had a recent service, check it out yourself anyway to be sure it really has been serviced properly.

P.S My two guide plates are not a lesson in good engineering. Instead they are a lesson in how to make something functional out of the scrap offcuts to hand, to do a job where it's hidden from view and it does not need to look nice and pretty.
 
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