Centreboard Removal

[IanS]

How is the pivot bolt sealed on your boat? I saw Andrew’s picture which shows minimal silicone sealant under the bolt head and nut.

I’ve just removed the centreboard and mine had a high mound of polyurethane adhesive covered by glass mat.

Any pictures or suggestions welcome.

Ian

[Peter T]

For mine, I turned up a nylon washer and a nylon cap that fits over both the head of the bolt as well as over the nut and fitted them with Silastic. Then I laid one layer of fibreglass over that on each side. If removal is required again at a later time, the layer of glass can be chiselled off again. Hope this helps, others may have other ideas also.
Sorry about the order of the photos, the second last one should be last

[IanS]

Thanks Peter, that’s really helpful. Very neat job.

[Ozzie]

viewtopic.php?t=255

Ian, the above, very old, thread has some stuff. Ian B mentioned my solution to leaks which is still working decades later. Top of a screw down plastic air tight food storage bottle from coles . You need the type that have big lids and flair out into broad shoulder under the lid. I put these on with sika I think or maybe silicone. They have the advantage of being transparent so you can see a leak while it’s still contained. Also if you screw the top off you can still get a suitable spanner in to tighten the bolt. Fortunately I’ve never needed todo either as no leaks …ever.

7A7E5A2A-9934-4A4A-B572-2EB78C0B77D0.jpeg (72.86 KiB) Viewed 6454 times

These may not be available as such any more but a screw top pasta jar would be similar. This was originally a smaller version there of. You need the hard, very transparent plastic. Needs to be cut with sharp fine saw.

Have not read the rest of the thread but maybe other stuff of interest there.

[IanS]

Thanks Ozzie, that was an interesting thread.

PS my recycled HDPE toe rails are now on. I’ll post details in the relevant thread. Now I just have to get the centreboard back in…

[IanS]

Centreboard removal and replacement was a drama. I had to do a rushed job to get the boat out of the boat yard. My first attempt leaked badly. My second attempt wept very slowly. I am just about to grind off all the glass and goo in the bilge and start again. Here's some pictures in case anyone is interested.

Image 1: laminex shim delaminated causing the centreboard to jam in the up position - not barnacles at all... Notice the shiny patch = bad galvanic corrosion lifting off the epoxy barrier coat.

Image 2: Another view of the laminate and nylon spacer

Image 3: pivot bolt bushing

Image 4: more galvanic corrosion

Image 5: new shims made from 1mm cutting board

Image 5: assembled with contact adhesive

Image 6: zinc anode ready for welding to the front edge of the centreboard

I also drilled a hole in the bottom front corner and attached a loop of 4mm double braid so if it ever gets stuck again I can pull it down while diving under the boat. Also, the double braid lift rope attached with a sewn eye showed no signs of deterioration after 2 years of immersion and use.

I'll post pictures of the pivot bolt finish when done (although it will not be anything like Peter's pukka job.

[Peter T]

Hi Ian, you are doing a great job. Just remember that the thing that wears out the bushes around the pivot bolt and the holes in the sides of the centreboard case is sideways movement of the centreboard port to starboard, so it is vital that those thrust washers each side of the centreboard are large enough and the correct thickness to minimise that movement as much as possible without having it jamb tight. This is also the reason I fitted a shaped nylon block tapered block to the inside of both sides of the centreboard case at the front. Leaving just enough clearance between them so that the centreboard when lowered to the full down position fits nicely between them also stopping the sideways flogging of the centreboard. Hope this helps mate and if what I said does not make sense, let me know and I will send photos.
Cheers

[IanS]

Thanks Peter,

I worried about the side-to-side slop. I started with three 1mm shims each side plus the nylon discs - this was too tight so I dropped off one 1mm shim on either side, and then it felt a little loose.

The other thing that's worrying me is the bearing surface for the bolt which appears to be just the hole in the fibreglass centreboard case. I can't understand how this hasn't become more oval shaped. Perhaps there is some kind of bearing fitted into the fibreglass. It's hard to explain and impossible to see (I need an endoscope).

I'll try and make a drawing (rough sketch attached) but if my question makes any sense to you I'd love to see a drawing or photo of your solution.

Now the boat is on the trailer again I can't get the centreboard out to have a good look.

[Andrew]

Gday Ian, that sacrificial zinc anode looks a good idea for moored boats.

If youve not already seen it, here is a link to my centerboard restoration blog page https://teria563.blogspot.com/2014/01/c ... refit.html It shows how the pivot bushes were done for Teria. So far its never leaked a drop since installed. Was just winging it at the time as there was little internet info about it then.

[IanS]

I did look very carefully at your blog. In the following image it looks like the plastic washer is half in a recess in the fibreglass, and therefore the bolt is bearing down on the washer which is in turn supported by the fibreglass.

Does that sound right?

I think part of my problem is that the recess in the fibreglass to take the thick plastic washer is worn down so no longer round and not supporting the washer.

Ian