Keel shims

[mambo]

Hello Brains trust.

I'm about to reinstall my swing keel.

I have 2 x 20cm thin (1mm or less) plastic octagon disks for either side of the keel. It strikes me that there will still be some gap between the keel and the inside of the keel box.

There is a hard plastic bush in the keel itself but it is only the same thickness as the keel.

Is there something I'm missing?

I read that some people have shimmed the keel with laminex disks which I don't have. However, I do have some thin stainless steel sheet it could cut down.

As always I'm grateful for any advice you might care to give.

Thanks

Ken

[Raya]

When I first replaced my centre-board (I've done it twice now), it had Laminex glued to either side of the board. I don't know if that was how it came from the factory. It seemed like the strips were used more to reduce friction than to act as spacers. I recall that they were octagonal in shape.

I installed thicker strips (Lamipanel) to take up a bit of slack for the new board. I haven't had any problems with this arrangement.

Your stainless would make ideal packing. I would still leave a bit of play in the board to help prevent jamming.

[Ozzie]

Hi mate I don’t know much on this topic as I’ve never had the cb out but I’m wondering if you’d have a problem with the dissimilar metals using stainless. I know the bolt is stainless but it has the bush. Perhaps the laminate will stop interacting between the metals. You could possibly use some Duralac in any area they are close. Watch it though it’s highly carcinogenic.

Good luck with it all.

[Peter T]

Hi Ken, if you would like to PM me, I can help you.

[Andrew]

I regalvanized and refitted Terias centerplate. Replaced the octagonal cheek washer/spacer (keel shim) with breadboard type slippery but strong plastic from a plastics supplier/manufacturer.(forgot what its called )

It was 2 or 3mm thick, and bought a bit extra. This was needed to shape a third plastic cheek washer to stop plate wobbling at the pivot area.

Shaped the cheek washers with rounded edges to get the most surface area possible between the plate and centercase.
The plastic was easy to cut with scissors or sharp knife.

Dissimilar metals - agree, wouldn't use stainless with a galvanized steel plate, the galvanizing could dissappear first then the steel may rust and expand, jamming the plate eventually.

Only have a ss pivot bolt, isolated from the plate by breadboard type plastic, selected and turned to shape by an engineer.

That was a few years ago, its still working well and no corrosion. Hope this helps, good luck with it.

[Manango]

I am in the middle of replacing my CB.
The following is what I have found on my boat.
The old CB was steel and extremely badly rusted, but I was able to determine that the thickness of the CB was around 12mm.
The width of the gap for the keel slot is 19mm.
I had my local steel dealer cut out a new CB for me out of 12mm black steel bar.(900mm x 280mm x 12mm)
The original CB had two thin sheets of poly (thin plastic) I know plastic is not the correct term, but my mind is blank at the moment. These sheets were approx 275mm diam and were glued (contact adhesive) onto either side of the CB with a hole for the hinge bolt / flange. Each of these were approx 2mm thick. Luckily they were still serviceable , after a major clean up, but 12mm for the CB + 2 x 2mm for the plastic = a total of 16mm going into a gap of 19mm. Just enough room to not be too sloppy and should not bind.
After assembly, I will be galvanising (cold gal paint) the whole assembly before I put it back in.
The SS bolt that acts as the hinge pin is approx 8mm diam and I that will be going through a neoprene or same type of poly plastic tube that will be pressed into the hinge hole in the CB. The tube has an outside diam of 30mm and has a internal hole for the hinge pin / bolt of around 9.5mm.
I can supply more details if you want.

[Andrew]

Here is a link to my blog which documented my centerboard refit, some of it may help. There was little info on the net then,

http://teria563.blogspot.com/search/lab ... rboard?m=0

There's other posts about how the boat was handled off the trailer etc

You blokes look like you're on the right track, Good to hear how it goes

[mambo]

Hi Again everyone

More advice sought please. I picked up my investigator today and I'm not so sure about the work I had done. There is now a 2-3mm lip on the inside of the CB case ( see photo ). My main concern is that this may allow excessive CB lateral movement and/or possibly chew out the plastic shims I put in there.

Does the team have any thoughts?

As always grateful for your input.

Mambo

[Peter T]

Hi all, I just had a thought re the large thrust washers each side of the centreboard. How about a couple of those old 33 1/3 LP records ? Not sure what thickness they are, but there you go. I used two washers made from 2mm thick nylon like cutting board material each side. My new centre board is Galvanised 10 mm thick steel. So if you do the sums. 10mm plus four thicknesses of 2 mm plus the galvanised should make this spot on. Also, the narrowest part of the centreboard case is actually at the pivot bolt and there is some flexibility there and the case gets wider the further towards the stern you go. Haven't fitted it up yet as I only rebuilt the pivot bolt hole on one side of the centreboard today. Once that has fully cured, will do the other side and then fit it all back together
Just a thought
As for the lip on the inside of your centreboard case, you might be able to sand this down to fair it somewhat by using the right grade of sanding paper glued to a piece of timber planed to the right thickness. Once done, you could then use a small roller to coat it with 2 pack epoxy undercoat. This can be done so long as you have the boat up in the air so you can get at it. Is this lip where they fitted a new section of centreboard case ? Is it near the pivot bold end or the rear ?

[Ozzie]

https://www.ebay.com.au/itm/16479240357 ... 9&targetid
Was it nolathane you used Andrew ?

In regards to your cb Ken there is a fair amount of “slop” for want of a better word in my cb. The possibility of chewing out of your washers would be an issue though. Can you get even hand tools with an extension up to smooth it all out.

Sounds a bit nuts but my dad used to make big suction washers for his yabbie pumps from old thongs. While reading these posts the thought crossed my mind that those rubber camping mats (the ones sans holes) would be ideal for shims if they were stronger and a bit thinner as they would damp any lateral movement.