Rudder lubrication?

Tim Mills

Tim Mills

.
Jul 6, 2017
158
Hunter H 41DS Hampton, VA
2004 Hunter 36
I removed the drag rod and tie rod ends to replace ends and noticed that the rudder is very stiff to move after the rod was disconnected. This maybe explains why the tie rod ends are worn.
Are there bearings for the rudder shaft?
Can they be lubricated or replaced? Or are they Teflon, UHDP? I have a fiberglass rudder shaft. Other than the stiffness, it all looks o/k. no play at all.
 
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Tim Mills

Tim Mills

.
Jul 6, 2017
158
Hunter H 41DS Hampton, VA
I tried some dry lubricant and worked it in some by swinging the rudder back and forth. It's a little better but still quite stiff. Looks like the bearings are UHDP. I've read that the plastic can swell if any petroleum based lubricant is used.
 
J

JimInPB

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Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
Cowpokee said:
Ultra High Density Plastic
Click to expand
I've worked with a lot of plastics. That's a new one on me. The closest thing to that name that I am familiar with is Ultra High Molecular Weight Polyethylene. Is that what we are talking about?
 
Cowpokee

Cowpokee

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Jan 8, 2015
360
MacGregor 26S, Goman Express 30 Kerr Reservoir
JimInPB said:
I've worked with a lot of plastics. That's a new one on me. The closest thing to that name that I am familiar with is Ultra High Molecular Weight Polyethylene. Is that what we are talking about?
Click to expand
I've worked with LDPE and HDPE but that was a new one on me also. I think Ultra High Molecular Weight Polyethylene is what we are talking about.
 
J

JimInPB

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Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
UHMWPE,
AKA High Modulus Polyethylene (HMPE),
AKA Poor Man’s Teflon.

Very High Impact Strength
Low water Permeability
A Bit Soft
Machines Well
Good Abrasion Resistance
Excellent Natural Lubricity (often used unlubricated as a low pressure bearing surface)
Coefficient of Friction Below That of Nylon.
Good Resistance to Most Chemicals, including salts

Available commercially in rods, sheets & bars. Most bar stock is low tensile. An "extra slippery" variant is available that is impregnated with oil from the factory & is specifically intended for use as a bearing material.

Strand oriented variants have very high tensile strengths (up to 350ksi) & are sold under the brand names Dyneema, Spectra, Power Pro, and Spider Wire.

UHMWPE has a high molecular weight & a long polymer strand length, but it is not super dense. If it was, then spectra would not float.

It does swell a little if soaked in some hydrocarbons like gasoline, oil, grease or chlorinated solvents. Strong oxidizers like bleach have a detrimental effect over time. Most non-chlorinated solvents don't seem to bother it at all.

I have a fair amount of plastic stock laying around the shop. I try to label everything because I usually can’t tell one from the other just by looking at it. If your plastic bearings are soaking up a lot of water, then they are probably not made of UHMWPE. Maybe something in the Nylon family????

Also possible, do you maybe have some barnacles growing in there somewhere?
 
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dLj

dLj

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Mar 23, 2017
4,443
Belliure 41 Back in the Chesapeake
UHMWPE would be an easy choice for rudder bearings. I would think Terry is correct that yours are likely the same material. UHMWPE doesn't tend to swell, so why is your rudder stiff? Could anything have moved, bent or warped? Barnacles or other debris getting in there definitely something to look at. Is the top bearing exposed to sunlight? Unless the UHMWPE is UV stabilized, it is not particularly UV resistant. Can you post pictures?

dj
 
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