Rudder bottom pin

Tamar

Tamar

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I have a small cruiser which has a transom hung rudder. It has two pintles on the stern, and under the blade it has a 16 mm pin which fits into a hole in the wooden keel.
On lift out I noticed the hole has elongated by about double.
What procedure would I use to repair it.
I thought about fitting a piece of hardwood under the blade with some sort of bush to take the pin. I know nylon is a no no because it swells when wet apparently.
Any alternatives I can use?
 
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Nylon is OK as long as you allow a bit of space for it to swell. I made a prop shaft bearing from nylon and it has given very good service - a lot better than the Cutless bearing it replaced. You might also find that a wooden bearing would last well - just fit a graving piece made from good hardwood into your deadwood and drill a suitable hole.
 
Tempting to suggest stainless steel, but I expect it would be good if the bush wore and could easily be replaced, rather than wearing the pin.
So I'd probably use a plastic like delrin.
 
neil_s said:
Nylon is OK as long as you allow a bit of space for it to swell. I made a prop shaft bearing from nylon and it has given very good service - a lot better than the Cutless bearing it replaced. You might also find that a wooden bearing would last well - just fit a graving piece made from good hardwood into your deadwood and drill a suitable hole.
Click to expand...
I thought about just putting a new piece of wood and drilling a suitable hole, I think that's what was there originally.
 
Wood will also swell when wet but would work for a while. A better solution would be delrin mentioned above which does not absorb water. Either a block let into the existing wood or a turned bush of suitable size. IGUS do a selection of bushes in various materials.
 
i managed to find an old picture. The pin is at the front of the blade and it looks white in the picture.
 

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oil filled nylon or bronze in a top hat bush, made with OD large enough to fill worn space. Lift rudder off . Machine out new hole in wood to just on / just under new bush OD. smear of Sikaflex 291i And press bush into wood with G cramp.
If you do it in bronze it will not need to come out for a LOOOOONG time.

regards clive
 
Has any consideration been given to the rudder pin material and the wear on that?
Oilon ( basically oil filled nylon without the problems of swelling) might be more gentle on the pin than something like bronze- Is that likely?
Makes one wonder if a piece of Elm, or Oak, or a similar hard piece of timber, as a bearing, suggested earlier, could be acceptable.
 
It was common to have a bronze domed washer under the rudder pintle. This was primarily to lift the rudder off the pintles on the transom but you do not appear to have a transom hung rudder. I would bore out the keel hole and use a delrin bush. Make it a press fit and epoxy it in place. This will strengthen the keel extension.
 
Daydream believer said:
Has any consideration been given to the rudder pin material and the wear on that?
Oilon ( basically oil filled nylon without the problems of swelling) might be more gentle on the pin than something like bronze- Is that likely?
Makes one wonder if a piece of Elm, or Oak, or a similar hard piece of timber, as a bearing, suggested earlier, could be acceptable.
Click to expand...
It's stainless rod. I'm going down that route I think although I have an oversized nylon bush 16.3mm
 
One alternative which might appeal is to make a stainless steel plate with correct sized hole and srew it down to the top of the wood. You might have to cut away the bottom keel part or the bottom of the rudder to make room for the thickness of the plate. You seem to have 3 pintles ie the 2 pintles and the bottom support. These of ourse must be in perfect alignement. ol'will
 
William_H said:
One alternative which might appeal is to make a stainless steel plate with correct sized hole and srew it down to the top of the wood. You might have to cut away the bottom keel part or the bottom of the rudder to make room for the thickness of the plate. You seem to have 3 pintles ie the 2 pintles and the bottom support. These of ourse must be in perfect alignement. ol'will
Click to expand...
I don't like the idea of stainless on stainless. I think the pin might wear
 
Quick fix would be to mix up some epoxy and graphite to 'pour' a new bearing, IF the pin is still round.... Or, lift the rudder and cast with a spare bit of bar of the right diameter.
Here, I happen to have delrin bar and a lathe, so would turn up a bush and 'pox it in.
 
Lignum Vitae is the traditional wooden underwater bearing material, can be sourced on Ebay: LIGNUM Vitae Crown Green Bowls. etc.

It will better protect the stainless shaft than would a plastic bush.

On any three bearing system, alignment is crucial. Hence it is probable that your pintles are well worn. The question is whether to do anything about that wear or to just leave them loose and let the top pintle and bottom bearing do the work. Do check that the hole wasn't intentionally enlarged to accommodate misaligned pintles and that the pintles do all of the work.

There are more readily available modern products but they are not quite as good: https://www.plantservices.com/articles/2005/469/
 
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