Rudder shaft - Grease or oil?

[Greg_Colleen]

Hi,

I've almost finished a refurbishment of a 28 foot Endeavour which has a tiller steer rudder. I removed the rudder because it was very stiff, so I've cleaned it all up and repainted it (the rudder, not the shaft) and I'm ready to install it back into the boat.
I would like to know whether I should grease the shaft before I install it, or should I use oil or some other product?
Any advice would be appreciated.

Thanks,

Wolfy

[Bill Seal]

install a zerk?

[capn ken]

Zerk and marine grease .?any bushings

[warren2]

Yes good idea. On my 30 ft first boat I installed a remote greaser since the rudder shaft was hard to reach

[Greg_Colleen]

No it doesn't have a zerk. So grease then, not oil?

[Greg_Colleen]

It has a nylon bushing at the top and the bottom of the shaft

[Wotname]

Originally Posted by Greg_Colleen

It has a nylon bushing at the top and the bottom of the shaft

Possibly not nylon, more likely Acetal which looks similar but doesn't swell in water.

If Acetal, then best lubricant is water, certainly not oil or grease.

See more here https://www.craftechind.com/top-5-ma...etal-surfaces/

[Greg_Colleen]

Thanks bud - much appreciated

[tkeithlu]

General way of thinking about it: Items that move slowly and do not have reservoirs (your rudder shaft) use grease if not lubricated by other means. Oil would leak out and be gone. Items that are high speed (transmission gears) and have reservoirs use oil. The higher the speed, the lighter the lubricant. Gears, with less heat and less speed use heavier oil (90 weight or so) than crankcases (30 weight or so).

There are intermediate cases like motorcycle drive chains, and exceptions like wristwatch pivots, but it lets you think about it.

[Boatyarddog]

Originally Posted by Greg_Colleen

No it doesn't have a zerk. So grease then, not oil?

Waterproof silicone grease!
Not Petroleum Based products.
SV Cloud Duster

[garyfdl]

I second what tkeithlu and Boatyarddog recommended.

As to zerks, they are easy enough to install BUT... you have to drill and tap the rudder shaft tube and then thoroughly clean it. You also have to be sure that the zerk(s?) doesn't penetrate too far into the tube - you don't want it to rub on the shaft. If the tube is not metal, I'd recommend dropping 2 drill sizes to make the hole, the tap can remove the excess material. If the hole us too small, move up 1 drill size. And drill slowly! Composites (like FRP) can heat up and melt and result in an oversized hole. Just a little bit of water on the spot where you're drilling will help prevent that (and flush away the debris/dust).

[tkeithlu]

The procedure Gary has carefully described.....take the rudder shaft out first! Pipe threads are tapered. You want the zerk to thread in securely but stop before you reach where the shaft would be and rub, as Gary cautions. Cut the thread kind of shallow, test for depth when the zerk is tight, cut a bit more thread if needed.

[zstine]

Wow Grease?! Water is generally the lubricant for plastic rudder bushings as far as I know.



Whatever you do, do NOT use petroleum grease like most axle grease. You have to be careful the grease is compatible with the plastic bushing.

[Wotname]

Originally Posted by garyfdl

I second what tkeithlu and Boatyarddog recommended.

.......

Why??

The OP has some sort of composite bushing, probably acetal (Delrin) and currently the tiller steered rudder is out of the boat.

It should turn free and easy dry fitted on the hard when it is refitted and if it doesn't, the cause needs to found and addressed.

Once launched, the water is sufficient lubricant. There is no need for any other lubricant, Zerks etc (IMO).

EDIT - crossed posted with zstine .

[fred4936]

Thank you for asking this question! There is a squeak coming from what must be the upper bearing of our Pearson 34-2. I am guessing it is Delrin, which would make sense. I will look into it as soon as the boatyard re-opens.