plastic rudder bearings

[tommojill]

The stearing on my dufour became really stiff over the past season so much so that the emergency tiller would not turn the rudder. Ive since been lifted out and dropped the rudder hopeing to find it full of growth but there was nothing except what looked like old grease that had gone hard. Has anybody got any ideas or had the same problem?

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[Oldhand]

If the "plastic" of the bearings is nylon, this is a common problem also experienced by older Dehlers. Nylon absorbs water over time and swells thus making the bearings tight. I suggest you fit new bearings made of PTFE.

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[tommojill]

Thanks for your help that would explain the tightness do you know where i could get ptfe bearings from?

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[Robin]

If you have a modern Dufour 'Classic' I think the bearings are roller type, the whole rudderstock, rudder and bearings being fitted as a unit and glassed into the hull. I don't know this system personally but it was used as a selling point when we trial sailed a Dufour Classic 41.

Otherwise yes some plastic bearings can swell, though enough is known about this to be rare unless someone has replaced the bearings and used the wrong material - nylon BTW is dreadful.



<hr width=100% size=1><font size=1>Sermons from my pulpit are with tongue firmly in cheek and come with no warranty!</font size=1>

 

[dralex]

I've got a Dehler 34 and will be replacing the rudder bearings this winter- the impression I got was that I'd have to get the bearings machined up specially, but that is should be pretty easy to do.

Alex

<hr width=100% size=1>Life's too short- do it now./forums/images/icons/wink.gif

 

[AndrewB]

Check the rudder stock is perfectly true, and the alignment of the bearings. Even the smallest fault will cause binding. A lot of nonsense is talked about "swollen bearings".

 

[Robin]

The swollen bearings nonsense was from the past where nylon and other unsuitable materials were used which swell when they absorb water, there are plenty of suitable plastics around now that don't do this. So unless someone has replaced the bearings with an unsuitable material that is unlikely to be the problem. A bent stock could cause it but I still believe you may have a system on the Dufour Classic which uses a complete stock/bearings/tube assembly fitted as an entity, with self centreing bearings. If that is the case the problem may be a bit out of the ordinary run of the mill DIY and some professional advice may be needed.

See <A target="_blank" HREF=http://jeanneau.tripod.com/id247.htm>http://jeanneau.tripod.com/id247.htm</A> which is a feature on a similar system fitted to a Jeanneau raceboat and the repair needed. Personally I like the old fashioned KISS system as fitted to our Jeanneau and every boat I've ever owned.



<hr width=100% size=1><font size=1>Sermons from my pulpit are with tongue firmly in cheek and come with no warranty!</font size=1>

 

[Twister_Ken]

Even kissier

>Personally I like the old fashioned KISS system as fitted to our Jeanneau<

Just hang it over the back like proper boats!

<hr width=100% size=1><A target="_blank" HREF=http://www.writeforweb.com/twister1>Let's Twist Again</A>

 

[ShipsWoofy]

Re: Even kissier

Just hang it over the back like proper boats!

Nah, that would mean you could release a snagged rope with a boat hook, or rig up simple emergency steering if things went wrong.

Ken, sorry mate, but that is your silliest idea yet.

<hr width=100% size=1><A target="_blank" HREF=http://www.topcatsail.co.uk>Woof</A>

 

[Robin]

Re: Even kissier

Who could argue with that? Ships Woofy could even turn his upside down to clear a jammed rope! /forums/images/icons/smile.gif

I hope I'm wrong though and that it's only the bigger Dufours fitted with self centreing rudder bearings. On the face of it the idea is very good, you get a very low friction system that has perfectly aligned bearings. Dufour's sales people told me (Dufour 41 Classic) it was expensive in component cost but offset by easier assembly to the boat. I suspect that fixing a problem one a few years down the line could get pricey.

<hr width=100% size=1><font size=1>Sermons from my pulpit are with tongue firmly in cheek and come with no warranty!</font size=1>

 

[Graham_Wright]

Don't use PTFE. Its very slippy but too soft and will absorb grit and wear out in no time.
Use UHDMWPE (Ultra high molecular weight polyethylene). If you can't find any, pm me.

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[snowleopard]

delrin is a standard alternative to nylon as it doesn't absorb moisture in the same way. it can be bought in cylinders of 2-4" dia and can be machined using woodworking machinery.

i fitted plastic roller bearings made by whitlock which are very low friction but i think you'd have to adjust the shaft diameter to match the standard sizes of rollers. for high-load spade rudder applications where the shaft can flex enough to make simple roller bearings bind, you can get spherical bearings but that's for really big high performance boats.

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[TheBoatman]

I've replaced a number of rudder bearings and I have always used marine grade Tufnol. My first set I fitted 15 years ago and they are still as good as the day they went in. It's bl**y expensive stuff to buy and you have to get it machined but once fitted forget about replacing any bearings again.

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[jonjo]

Re: Even kissier

> I hope I'm wrong though and that it's only the bigger Dufours fitted
> with self centreing rudder bearings.

Um my Match 35 will be arriving with something similar. Not sure if a or :-( is more appropriate!

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[Ships_Cat]

Ah, a very sensible person.

I do not know why people get into the other plastics because Tufnol (and the thermosetting resin Thordon) takes a lot of beating and has been well proven over the years.

John

<hr width=100% size=1>I am the cat but I am only 6.

 

[Robin]

Re: Even kissier

I don't know that much about them, the idea sounds good and it seems to give a light and positive helm at least on the Dufour we sailed. I just happened to see the article on the Jeanneau website about the repair of a seized one on a JOD35, I don't think Jeanneau fit them on most boats in their range though and certainly not on our SL41 from 1988.

<hr width=100% size=1><font size=1>Sermons from my pulpit are with tongue firmly in cheek and come with no warranty!</font size=1>