Forum - Keel and Centre Plate - Un-sticking a Swinging Keel
|Un-sticking a Swinging Keel||20||Thu 29 Apr 2021 21:51:38|
|Red Herring Sat 30 May 2020 14:33:37|| Red Herring is finally afloat on the River Cam. As expected, her swinging keel doesn't want to swing down; not surprising as she hasn't been on the water for 3 years and I'm not sure whether the owner before that ever bothered to lower the keel. I thought I would try to shift it by tapping on a long rod through the hole in the SS plate where the chain goes. First attempt was with a wooden rod 18 mm in diameter; that got so firmly stuck that it took me a long time to get it out. Next was an iron rod 15 mm in diameter; as soon as that started to stick I gave up. So advice please:|
- how wide is the slot in the ballast keel through which the centre plate swings? This will determine the maximum diameter of any rod I use at the next attempt.
- am I on the right track, or should I stop this approach for fear of causing damage? Ultimately, I would rather sail with only the ballasts keel to counter lee way that break something that I can't see and don't really understand.
|Mark Sat 30 May 2020 23:18:26|| Normally a tap on top of the centre plate with a hammer and metal rod through the chain hole will do the trick but if it isn't then it must be well and truly rusted.|
It is quite hard to get the rod on top of the plate. There isn't anything mechanical in there but it is hard to see things down the chain hole. If your rod is getting stuck then I think it may be going down between the side of the plate and the side of chain box - note that when the plate is up, the top of the wide back end (chain end) of the plate is inside the chain box which is above the cast iron keel. There is a picture of the inside of the keel in this blog https://manta19.miwd.co.uk/blog/83/114. Not sure how much space there is in the chain box but you are good at limbo have look under step inside the cabin and you'll see.
Be careful not to hammer too hard because the chain box is only fibre glass and you would want to split it open.
I think you'll find your Manta will sail fine if the plate is stuck up. You just might make a little bit more leeway when close hauled.
|Red Herring Sun 31 May 2020 16:10:34||That's really helpful Mark. I will proceed with caution. I've never tried looking into the bowels of the boat, so it will be an interesting experience.|
|Red Herring Sun 12 Jul 2020 23:10:23|| I tried to follow your advice Mark and took out the lockers under the cabin step, but I found that the chain was completely enclosed in a fibreglass pillar that rose from the bottom of the hull to the step, so I could see absolutely nothing within it. I think my only option is going to be to have the boat lifted either in slings or onto a cradle and then to get underneath with a saw to try to free the plate from the stub keel, as suggested in another post. It may take me some time to find a boatyard on the Cam or Great Ouse who will do the lifting.|
If I were sailing on a lake I probably wouldn't bother, but the river is so narrow that the excessive lee way, particularly in light winds, is unacceptable.
|mhsorens Mon 13 Jul 2020 16:46:23||As you found out yourself, there is NO access to the centreboard box from inside the cabin and I wouldn't advise removing the metal plate in the cockpit as it also serves to hold together the two glass fibre halves of the box. If you are not able to gently tap the keel loose from above, *through* the holes in the metal plate, I'm afraid your only option is to hoist the boat in order to free the stuck centreboard from below. That, however, is pretty easy - just remember to secure the centreboard lifting chain as you won't want the centreboard (25 kg) to drop on you in the process: What worked for me was using the thinnest possible handsaw to remove the expanded rust between the ballast keel and the centreboard. I would expect maybe 1-2 mm's of rust on each side (corresponds to 0.1 mm of uncorroded metal lost). While having the centreboard free of the water, I would inspect the chain attachement to the centreboard, the protruding "stopper" as well as the pivot bolt holding the centreboard in place.|
|Red Herring Tue 21 Jul 2020 10:09:56||That's really helpful advice - many thanks! I think I have found a marina on the River Cam with a hoist who may be prepared to lift Red Herring for me. I plan to slacken the chain by only 5 or 6 links to start with so that the plate won't move far when/if it comes free; then I can slacken it completely to see and clean up the whole exposed plate. I wan't intending to take out the pivot pin for fear that the whole keel plate would drop out; I thought I would leave that until next winter when she is on her trailer and the keel can't drop. I will certainly take a couple of narrow, stainless steel shackles in case I need to replace the connection to the chain - I have read the post suggesting cutting off the protruding end of the pin after damaging the threads to prevent it working loose. Never haviong seen the keel I don't know what the 'stopper' is, but I'm sure it will be clear when I see it. I'll let you know how I get on.|
|Red Herring Thu 13 Aug 2020 10:11:55|| I had Red Herring lifted out yesterday and spent two and a half hours under her in a temperature of 34C, working to release the swinging keel. I sawed through both sides of the plate, easily at the aft end and with increasing difficulty as I approached the pivot pin, but I got through almost all of it. However, although the plate has some slight side-to-side movement, it won't budge at all in the vertical plane. I managed to get a grip on the very end of the plate with a pair of pointy-nosed pliers and it felt as though I was pulling against some mechanical block: no give whatsoever. With some tredpidation I took out the pivot pin, which came easily, being of stainless steel and apparently working through a tube in the plate, but no movement resulted. So I paid and thanked the boatyard, was put back into the water and motored home with a keel plate still firmly wedged inside the ballast keel.|
So what may be wrong and what can I do about it? Is there any way of getting to see the top of the swinging keel without breaking into the structure of the boat? Advice please.
|Ian & Julie Thu 13 Aug 2020 20:21:43|| we finally released ours with the help of some penetrating oil squirted down from the top. We also had to use some pretty hefty blows with a big hammer and steel rod. This is not a job for the faint hearted ! |
We found a cheap boat lift by asking a JCB owner. https://manta19.miwd.co.uk/blog/25/93
|Red Herring Fri 14 Aug 2020 18:34:44||Thanks for the advice. I used release oil too while sawing, but even that didn't suffice. How did you find the entrance to the keel box from on top? I can't see any way of doing it.|
|Ian & Julie Sat 15 Aug 2020 13:38:27||The iPhone has a torch and if you select its brightest setting you can get one eye plus enough light to get a decent view. I knelt behind the top cover facing the bow. If your keel was like ours you won’t be able to see down the side of the keel as rusting seems to expand to fill the keel box. For best leverage I banged down on the keel as far forward as I could. To be honest when we managed to drop our keel , by the time we’d angle ground the rust off there wasn’t much left.|
|Red Herring Sat 15 Aug 2020 15:07:40||I'll go and have another go at it, trying your technique, but Red Herring is now back on the water, so I hope everything that should hold does hold.|
|Red Herring Mon 17 Aug 2020 10:23:45||This time I used a narrower rod and a bigger hammer and was careful to locate the rod on the top of the plate by feel (I couldn't see anthying through the chain hole). When I hit the rod with the hammer the sound was as of metal on metal, hammer on anvil, so I am reasonably confident that the alignment was correct. However, there was absolutely no movement and that clear ringing sound implied to me that the plate was no longer rusted to the ballast keel. I have spoken to the previous owner who says that he lowered and raised the plate at the start of the 2019 season with no problem. But there is something preventing its movement and I cannot work out what it might be. Any other ideas?|
|Red Herring Sat 22 Aug 2020 12:09:30|| The last thing I could think to try was removing the square plate that the chain runs through in order to get a better look at the top of the keel. Despite dire warnings on other posts, removing the plate wasn't a problem. To get at the 8 nuts underneath the plate you need to remove the wooden lockers beneath the bridge deck; take the locker doors off and, on Red Herring anyway, there is just one screw to take out from the floor of each locker at its outside front corner. It's then quite easy to hold each nut with a 5/16" spanner in one hand and to unscrew its bolt from above; ideally you will use an electric screwdriver, or at least a ratchet one, as there is a lot of unscrewing and later screwing back to be done - I didn't! With the bolts removed you will need to prise the plate up to break the seal. And then you see a rough-cut oblong hole, about 1" by 2" through which the chain runs.|
What I had forgotten was that the top of the keel is about a foot under water, so I still couldn't see it - doah! So I put it all back together again and will leave it until the boat is next out of the water.
|Ian & Julie Tue 25 Aug 2020 13:35:14|| I know just how you feel ! One thing else I remember is once our keel bolt eye was fixedL by welding a nail to create a new eye , there wasn’t enough chain then to bring the keel back to where it once was, so extra links were put in but then of course you don’t then let the keel down on it’s full length again. I got the swimming goggles on and raised a finger when my wife gently lowered it to the correct depth. Something like ten links down now. This is all for when you eventually solve your recalcitrant keel !|
|Mark Tue 01 Sep 2020 07:00:12||'Recalcitrant' - what a great word, new to me, just googled it|
|StuartH Fri 25 Sep 2020 14:05:22|| I Red Herring I had exactly the same problem with Davin, unfortunately I'm pretty sure you will find it is due to more rust!|
I found that like you even with the pivot pin removed things were still solid, remember I large portion of the swinging keel at the forward end never comes down, what I found was this end was almost solid with rust.
I would do what you did before - remove the pivot pin and with a thin tool - screw driver/chisel whatever fits up there knock as much as you can out - eventually it will start to move.
|Red Herring Thu 05 Nov 2020 17:42:02|| So eventually I did seek professional help. Hurriedly brought forward in advance of the second lockdown, I towed Red Herriing to a small boat-builder near Woolverstone on the Shotley peninsular. It took him nearly 2 hours to get the keel out, using a variety of tools and a deal of force. When it came out it was possible to see that the plate was not only rusted, but also slightly bent. Presumably Red Herring had been run aground at some stage sufficiently hard to bend the plate. Then, the next time she was loaded onto her trailer the plate was forced up into its casing and there it has remained ever since. Anyhow, the plate has now been straightened out, more or less, cleaned up, painted with primer and returned to its place on the boat, apparently working fine. |
So Red Herring's problem was exactly as described by Stuart with the addition of distortion, which was the real killer. Actually, once the rust was scraped off and the bend straightened the plate was in surprisingly good condition with no wear at the pivot pin hole.
So now all I have to do is to wait until March or April to find how she sails with a proper keel. Looking forward to it.
|Ian & Julie Fri 06 Nov 2020 09:01:05|| Good old Stuart - we’d be lost without him on this forum ! Great news for you though. |
Funnily enough we did sail for a while without a keel and to be honest , we barely noticed , as the 'stub' keel , tracked and pointed really well.
|Red Herring Fri 06 Nov 2020 18:47:56||Doesn't work very well on an over-grown ditch like the River Cam though!|
|Red Herring Mon 05 Apr 2021 10:42:41|| Red Herring went into the water again for the first time on that glorious Easter Sunday and the keel swung down with a satisfying clunk. Very reassuring! Now all I have to do is to wait for the bitter weather to pass to see how well she sails with a proper keel.|
|Red Herring Thu 29 Apr 2021 21:51:38||And she's really pretty good, though there is always too little or too much wind, but sailing is like that!|