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ChrisC  
#1 Posted : 16 November 2004 19:18:00(UTC)
Rank: Advanced Member

Posts: 105
Location: WOODBRIDGE, Suffolk

I recently (June) purchased a Seal 28, and I'm delighted with my choice, having recently completed a channel crossing.

However, there is one problem that I wondered if anyone has come across before? When the keel is in the down position and the boat rolls, a banging noise comes from the keel. In the sheltered waters of the Solent, this was not too noticeable, although it did concern me somewhat and I was intending to look into the problem over the winter. However, when crossing the channel with a relatively big following swell (1-2 metres?), the banging coming from the keel was very loud, and I had to lift the keel considerably (around half way up) to stop the noise. Fortunately I was on a broad reach crossing the channel in both directions (good planning or luck...) so I was able to do this.

I believe that the keel is moving laterally and in fact I once took the cover off and had a look into the keel box whilst underway. Its possible to see the keel moving by about 1mm from side to side which causes the banging.

In case it is relevant to the problem, the previous owner replaced the keel lifting wires last winter and I was wondering if these are not quite the correct length, so that the keel is not going down quite as far as it should and is "swinging" on the wires.

Anyway, if anyone has any ideas then I'd be glad to hear about them. The boat will be lifted out on 28 October and I'm very keen to get this problem properly fixed for next season - if there is anyting that I need to try before the boat comes out to confirm the cause of the problem then I need to do it fairly soon.

Thanks for any advice you can give me.

Chris

Chris Callender

Mike Edwards  
#2 Posted : 16 November 2004 19:18:00(UTC)
Rank: Advanced Member

Posts: 168
Location: Thames Area, Essex

You should be able to wind down the keel so the cables go slack, when my keel is supported on its cables it tends to knock.

The dimensions of the keel cables are in the SSA handbook for the 28 I believe, If you have any difficulty I still have my old ones I can measure these, You should make sure the worm shaft is the same length and thread as well.

Mike Edwards

Mike Edwards

Seal 28 "Aztec"

ChrisC  
#3 Posted : 16 November 2004 19:19:00(UTC)
Rank: Advanced Member

Posts: 105
Location: WOODBRIDGE, Suffolk

Hi Mike,

Thanks for that - I'll bet that the new wires are a bit on the short side (maybe they still need to stretch a bit!). I'll check whether the wires are slack next time I'm down there.

Thanks

Chris

Chris Callender

Lee Taylor  
#4 Posted : 03 June 2020 13:12:38(UTC)
Rank: Member

Posts: 13

Hi there all, I hope everyone is well! Great that we're able to get out sailing again now!!

This is an old thread of course, maybe even the oldest :) I have Chris' old boat now, currently called "Whiskey Mac". I finally got out on her at the weekend there, and it was fantastic. There was however when in maybe 5-6 foot swell a banging still occurring and Chris described above. Whether he fixed it and it's returned i don't know, but it is present.

We checked the cables and the worm drive components whilst replacing the lifting eye and the cable seem to be long enough. Whilst dropping the keel, the cable and handle get loose once fully unwound. This suggests to me that the keel is fully lowered.

My thoughts are that either there is some rusting or foreign objects in the bottom of the well stopping the keel completely lowering, or that there is some wear to the nylon guides(as i read somewhere in another forum, regarding the 22 i think).

Does anyone have any advice about this please? It makes things far less peaceful. I'm also a little concerned there could be some damage to the well molding, which could be catastrophic since it's below the water line.

She's a MK2

Many thanks in advance ofr any advice.

Regards,

Lee

Whiskey Mac

Neil Sinclair  
#5 Posted : 13 June 2020 20:33:45(UTC)
Rank: Advanced Member

Posts: 104

Hi there, Lee - glad to hear you're out and about already. Andi was launched about a week ago but I haven't managed to get the sails up yet. Next Monday is the day! You say you're getting the banging from the keel in a lumpy sea - is that while heading into it? If so, it might be your keel is swinging front to back. The keel on Andiamo (Mk 1 boat) has a large plastic block on each side. The blocks slide in channels in the side of the keel box. The blocks are secured to the keel with two large s/s bolts through the whole assembly. If the bolts are slack, or the blocks are worn, the keel will be able to rock back and fore and bump on the external iron ballast. Maybe you could push a couple of pieces of stiff rubber hose down the box, front and back, to cushion the keel?

All the best! Neil

Neil Sinclair

Seal 28/27

'Andiamo of Exe'

Lee Taylor  
#6 Posted : 17 June 2020 14:59:24(UTC)
Rank: Member

Posts: 13

Hi Neil, thank you very much for taking the time to answer :)

Yes i got wind of the lockdown before it happened and got the crane in straight away, as i thought he would not be allowed to come on the lockdown. Little did i think or realise that even solo sailing would also be off limits. So she sat in the water until we were allowed. Literally on the day it was announced up here that sailing was allowed, i headed out.

Hope your launch went well and you too are getting out and about now!!

Thanks for your suggestions.

I'll try listening with that in mind but the movement definitely seems to be from side to side, port to starboard. Makes a bit or a racket and shakes the boat a bit. Does this sound normal or can i do something about it?

All the best to you too :)

Lee

Whiskey Mac

Neil Sinclair  
#7 Posted : 19 June 2020 21:09:24(UTC)
Rank: Advanced Member

Posts: 104

Lee - all I can suggest for now is try sailing with the keel right up. Andi manages to get along making about 10 degrees leeway like that and you have 6 inches more draught. You might find the steering gets a bit heavy, though.
Neil Sinclair

Seal 28/27

'Andiamo of Exe'

Lee Taylor  
#8 Posted : 24 July 2020 19:34:19(UTC)
Rank: Member

Posts: 13

Hi Neil/all,

We decided to do what we could to remedy the banging this season, with the boat in the water on its drying mooring. As suggested elsewhere we packed out the nylon(Or whatever they're made of) out with some steel sheet. We did this by making an A-frame in the saloon for a crane hoist. We tried 2*2mm sheet on each side, so 8mm in total. This did not lower and the keel jammed about half way down. Removing 2 of the sheets leaving 4mm altogether allowed the keel to lower without jamming.

We took her out around Ailsa Craig in a fresh breeze to test. Mostly beam reach. There's still a little bit of banging but it is massively reduced and now not worrying in the slightest.

All in all the job only took about 4-5 hours. We had some difficulty getting the hoist hook back out of the lifting eye so the keel could hang on the lifting mechanism and resolved to wait until the tide went out. This allowed us to rest it on the bottom whilst we swapped over. Something to bear in mind if your mooring doesn't dry out.

There was some rounding on the outer edges of the nylon blocks, as though at least one of them has been resting on a raised point. I expect the block is now shaped itself to fit the contact points on the stub keel.

Another point noted, and we're not sure whether this is meant to be the case, or a result of wear(Perhaps someone can comment?): If looking at a cross section of the nylon blocks, e.i. as if looking down in to the well along the length of the keel, the block looks like a lower case "n". With a lower section in the middle to house the rods and nuts. The forward raised/thicker sections were wider/thicker than the aft ones. This left me wondering whether some or maybe most of the movement was actually rotational. Rotating on a vertical axis centered on the forward sections of the nylon.... When we have her lifted out at the end of the season i will drop the keel whilst it's on the crane and investigate any degrees of movement. We may also go back and try 6mm altogether in stead of 4mm if we find it still bangs in other sea states.

Thanks again for the input!

Lee

Whiskey Mac

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