Best bush material for Pintles & Gudgeons?

MiddayGun

Super Anarchist
1,178
442
Yorkshire
I have a transom hung rudder on my boat, when I first bough her there was a fair bit of play in the rudder, noticeable when shifting between pushing & pulling. 

I had a local guy bush them, I think he used some kind of Bronze alloy, which worked for a few years, but now I'm starting to get some small play back again. Nothing significant, but enough to be annoying.  
The alignment was also thrown out last time, making it hard to get the pin in, so I'm going to replace them all again and align them all the bench, just wondering what the best material is, maybe some kind of plastic?

Only the bottom bearing gets any lubrication, the top is out of the water.

IMG_0376.JPG

 

Zonker

Super Anarchist
9,641
5,607
Canada
Only a maniac tries to align 3 bushings.

Acetal if you want to try plastic. It doesn't swell very much (have to look it up). Other plastics are just too soft and will wear out. Nylon and UHMW both swell in water more.

 

MiddayGun

Super Anarchist
1,178
442
Yorkshire
Only a maniac tries to align 3 bushings.

Acetal if you want to try plastic. It doesn't swell very much (have to look it up). Other plastics are just too soft and will wear out. Nylon and UHMW both swell in water more.


Cheers. I'll look it up. 
And yeah, its the only rudder I've had with 3 sets of bearings. 

The centre one isn't a tight fit though, it's not bushed (and never was since I had the boat), not sure if it was intended for extra support but I can't see it doing an awful lot.
I'd get rid, but then I'd need to fill the holes, match the gelcoat colour & more than likely still have a patch that looks different under the bracket.

 

Will1073

Anarchist
743
138
Stainless pintles?
 

I have always gone for bronze bushings and had extras made that can be pressed in after a few years.

 

10thTonner

Hazard to Navigation
1,616
582
South of Spandau
I'd get rid, but then I'd need to fill the holes, match the gelcoat colour & more than likely still have a patch that looks different under the bracket.
First world problems, eh? 
 

How about taking a big drill and widening the center one so far that it doesn’t have any contact at all? Then it’s still there but only for decorative purposes. 
 

Another idea would de filling the holes with… screws! Nobody would know they don’t serve any other purpose than covering these holes. 

 
Last edited by a moderator:

MiddayGun

Super Anarchist
1,178
442
Yorkshire
Another idea would de filling the holes with… screws! Nobody would know they don’t serve any other purpose than covering these holes. 
I would though, so its not happening. 

I'll leave it for the moment, it doesn't seem to be doing much anyway right now & as I said above, its not a tight fit. Presumably Rob Humphries put it there for some reason other than keeping the stainless fabricator busy.  

 

IanA.

Anarchist
801
522
Amsterdam
I have a transom hung rudder on my boat, when I first bough her there was a fair bit of play in the rudder, noticeable when shifting between pushing & pulling. 

I had a local guy bush them, I think he used some kind of Bronze alloy, which worked for a few years, but now I'm starting to get some small play back again. Nothing significant, but enough to be annoying.  
The alignment was also thrown out last time, making it hard to get the pin in, so I'm going to replace them all again and align them all the bench, just wondering what the best material is, maybe some kind of plastic?

Only the bottom bearing gets any lubrication, the top is out of the water.

View attachment 501753


How tight do the pins fit inside the holes of hull mounted gudgeons? You might be getting excessive wear because of asymmetric loading on the pin. Consider welding the pins in place to the hull mounted brackets(turning them into pintles).  A bit like the Seasure style pintles below but obviously sized accordingly to your loads. 

image.png

Alternatively you could go with a top and bottom supported gudgeon which is probably more robust and easier to align. These are what the melges 24s use with fast pins for easy removal. 

image.png

image.png

 

MiddayGun

Super Anarchist
1,178
442
Yorkshire
How tight do the pins fit inside the holes of hull mounted gudgeons? You might be getting excessive wear because of asymmetric loading on the pin. Consider welding the pins in place to the hull mounted brackets(turning them into pintles).  A bit like the Seasure style pintles below but obviously sized accordingly to your loads. 

View attachment 502383

Alternatively you could go with a top and bottom supported gudgeon which is probably more robust and easier to align. These are what the melges 24s use with fast pins for easy removal. 

View attachment 502384

View attachment 502382
I'm erring towards your last suggestion to be honest. 
Remove the middle set entirely & replace the top & bottom with two sides ones formed from 316 stainless plate, something like the J/88 ones.

image.png

I'll keep the single long bearing shaft / pin. 
I've been meaning to set up a laser level line across the back of the keel & rudder to check for alignment for a while now as the helm feels different on opposite tacks. At the same time I can re-align the brackets with some thickened epoxy underneath to so that they naturally find their best alignment. (not sure if I how I described it makes sense, but it does in my head! 

 

Zonker

Super Anarchist
9,641
5,607
Canada
Thicken epoxy with cabosil but also a bit of milled fibers for such high load bearing pads such as you suggest. Good idea by the way.

 

Latest posts




Top