Rudder bushing material? Delrin, PTFE, UHWM, VHF, CIA.. - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > General Interest Forums > Gear & Maintenance
 Not a Member? 
  #1  
Old 12-26-2013
Member
 
Join Date: Sep 2011
Location: Maryland
Posts: 83
Thanks: 6
Thanked 1 Time in 1 Post
Rep Power: 3
Reefpoints is on a distinguished road
Rudder bushing material? Delrin, PTFE, UHWM, VHF, CIA..

I recently pulled down my rudder and noticed the bushing (not the regular rudder bearings) that sits between the top of the rudder and the bottom of the hull has been worn down to just about nothing.

I plan on buying some bushing material and cutting it myself with an adjustable hole saw (prices seem reasonable, less than $20 for a 1/8" sheet 1 foot by 1 foot online) but I don't know what material is best - there are so many to choose from: Delrin, PTFE, UHWM are what

Does anyone have any experience or advice? TIA!

Photos below:




Reply With Quote Share with Facebook
  #2  
Old 12-26-2013
Faster's Avatar
Just another Moderator
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 14,390
Thanks: 63
Thanked 160 Times in 157 Posts
Rep Power: 10
Faster has a spectacular aura about Faster has a spectacular aura about Faster has a spectacular aura about
Re: Rudder bushing material? Delrin, PTFE, UHWM, VHF, CIA..

I'd call that a washer rather than a bushing.. and it's kind of unusual to see one there in our experience. Probably doesn't matter what you use, though I do know some nylons expand when immersed in water - used it for a bottom bushing once, had to ream it out because it became a tiller lock in a month or so!! But that was a real bushing/bearing, not just a washer like what I see in the picture.
__________________
Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Reply With Quote Share with Facebook
  #3  
Old 12-26-2013
RichH's Avatar
Senior Member
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 2,581
Thanks: 9
Thanked 40 Times in 36 Posts
Rep Power: 14
RichH will become famous soon enough
Re: Rudder bushing material? Delrin, PTFE, UHWM, VHF, CIA..

What youre probably referring to is a thrust washer and its probably delrin which was commonly used for such marine bearing and thrust washer applications.

Delrin, alone, is relatively poor choice for such applications as its wear (abrasion) characteristics are dependent on the smoothness/roughness of the surfaces that it interfaces with. Delrin applied against macroscopically 'rough' surfaces will quickly abrade away by 'transferring' itself to the roughened surface. Delrin in such 'plain bearing service' usually must 'ride' on mirror polished surfaces - similar visually to the 'bright' surface of your exposed rudder shaft.
UHMWPE or 'teflonic' degradation via abrasion will be similar to delrin.
The answer here is to provide a smooth mirror polished surface, etc. for whatever the polymer bearing material you choose to 'ride' on.

Usually this type configuration was found on boats with tillers and usually there was such a thrust washer under the tiller head - directly connected to the rudder shaft. The thrust bearing was to alleviate friction between the tiller head and the FRG tube which contained/constrained the rudder shaft ... and the delrin thrust bearing usually only lasted a season or two, then 'fell out' due to extreme abrasion wear. Some bearing designs for this configuration had the thrust bearing portion as a part of the rudder bearing .... the bearing looked like a hollow 'top hat'.

You might find other solutions to this situation by doing an intensive internet search for "Pearson + 26 + rudder bearings" as this delrin problem with boats and rudder bearings has been quite constant over the years. The Pearson 26 owners group had published several successful 'work arounds' over the years --- but I dont know if this info is still available on the net.

:-)

Last edited by RichH; 12-26-2013 at 07:29 PM.
Reply With Quote Share with Facebook
  #4  
Old 12-26-2013
Member
 
Join Date: Sep 2011
Location: Maryland
Posts: 83
Thanks: 6
Thanked 1 Time in 1 Post
Rep Power: 3
Reefpoints is on a distinguished road
Re: Rudder bushing material? Delrin, PTFE, UHWM, VHF, CIA..

Very helpful, I will look into the Pearson 26 issue. I certainly don't intend to change this every year! Right now, the rudder top is wearing away (as is the bottom of the hull) from rudder movement.
Reply With Quote Share with Facebook
  #5  
Old 12-27-2013
RichH's Avatar
Senior Member
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 2,581
Thanks: 9
Thanked 40 Times in 36 Posts
Rep Power: 14
RichH will become famous soon enough
Re: Rudder bushing material? Delrin, PTFE, UHWM, VHF, CIA..

Here's a iisting and solutions offered by the P26 folks as regards this common (delrin) rudder bushing issue, etc. Such may be helpful to you on your non-Pearson 26/30 boat that has this rudder bushing configuration.

Rudder Bushing Repair Details - Pearson 26
Rudder Bushing Consderations - Pearson 26
Rudder Bushing Repair Alternative - Pearson 26

take note in the Rudder Repair Alternative posting the usage of DIY made bushings using filled epoxy + carbon powder ... I can attest that such a choice of materials will outlast most 'store bought' materials in such applications, especially if you add very finely chopped up Gore-Tex fibers to the 'mix' - I preferred GoreTex dental floss as the top layer of my 'epoxy filler'. Again, the secret here is a smooth and polished surface to 'run' against.

Last edited by RichH; 12-27-2013 at 11:40 AM.
Reply With Quote Share with Facebook
  #6  
Old 12-27-2013
Member
 
Join Date: Sep 2011
Location: Maryland
Posts: 83
Thanks: 6
Thanked 1 Time in 1 Post
Rep Power: 3
Reefpoints is on a distinguished road
Re: Rudder bushing material? Delrin, PTFE, UHWM, VHF, CIA..

Those were very interesting - in the end it seems most folks are using the delrin - either the stock ones from D&R marine or fabricating their own.

I liked the third link alot, it explains a good way to fill the tube with epoxy and graphite to from a long continuous rudder bearing. That's on my list of things to do this spring..

I have a sort of whacky idea for my thrust washer, thoughts would be appreciated:

On the top rudder post mating surface (underside of hull at shaft opening): I will rebuild the rough surface with an epoxy & graphite mix. This way the upper surface will be smooth and fairly low friction thanks to the graphite.

Now for the lower surface (top of rudder where the shaft exits the rudder): I could have a shop make a stainless steel washer (316 stainless), but it would have a slightly enlarged inner diameter, say 1/4" too wide. I would then epoxy that washer in place centered on top of the rudder. This way the washer would not corrode or cause corrosion with the shaft (since I don't know what grade steel it is) because it would be offset from the shaft by a 1/8" gap filled with epoxy.

In my mind, this seems like a great solution - the compression washer won't scrape away in a year or two and no shaft corrosion. So I'm sure I'm missing something - what is it?

Do the plastic (delrin) washers act like shock absorbers - meaning the steel would just be too hard to use in this situation?

As always, anyone's thoughts, insights, or experience would be greatly appreciated!
Reply With Quote Share with Facebook
  #7  
Old 12-27-2013
RichH's Avatar
Senior Member
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 2,581
Thanks: 9
Thanked 40 Times in 36 Posts
Rep Power: 14
RichH will become famous soon enough
Re: Rudder bushing material? Delrin, PTFE, UHWM, VHF, CIA..

I agree with your recent thoughts ... except that filling the entire length of the rudder shaft tube is not really necessary as all you need is a top and bottom bearing/bushing. Too long of a single bushing will be hard to control especially if you have any 'bend' or 'out of round' at all in the rudder shaft.
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Irwin Rudder Bushing ontour Irwin 1 11-30-2010 09:37 PM
Rudder bushing worn out (F-24 Mk1) brak Gear & Maintenance 0 11-12-2010 06:35 PM
Lower Rudder 2 Part Bushing Dolby Gear & Maintenance 4 11-12-2009 07:43 PM
upper rudder bushing kitejunkie Seafarer 2 02-06-2009 07:31 AM
rudder bushing material, loads Burnsy Gear & Maintenance 2 01-22-2004 06:36 PM


All times are GMT -4. The time now is 08:38 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012