Rudder almost seized after 3 years in yard

[Puffinclub]

My 40 foot steel cutter has been in a cradle stored 3 years. It is tiller steered. When the boat came out of the water the rudder was totally free swinging, ashore... it is very, very stiff to move now, 3 years later. The long keel only supports the rudder at its heel - a pin and synthetic washer. The shaft is approx 65mm or 2.5" approx. The rudder trunk is approx. 90mm or 3.5" OD stainless pipe and the assembly has bearings at deck level and as the shaft exits the hull. All the bearings are "delrin" or "thordon" or similar. They were installed as a loose fit - quite loose. Now the one at the hull (below waterline) is swollen so tight I can barely move the rudder with a 2 metre tiller arm. After one year ashore the rudder is usually a little tight and loosens up once launched. so I sealed up the shaft exit and filled the trunk with water for a week, no real improvement. I tried detergent in the trunk...no difference.
I would have thought a bearing would shrink once dry...not swell up?
Can anyone explain why this has happened, and how I should proceed, please?

[GordMay]

Greetings and welcome aboard the CF, Puffinclub.

[JPA Cate]

Hi, Puffinclub,

We have had nylon bushings swell up. They swell from salt water exposure. The cure was to drop the rudder, and ream out the bearing to about .010 oversize. Jim actually made the reamer. That cured the problem for the remaining period we owned the boat, about 15 yrs.

It is only a guess, but mine is that that is what has happened to yours, as well.

Good luck with it.

Ann

[Captsteve53]

A Couple of points with these types of materials:
1) ABSORPTION ALLOWANCE
Thordon normally absorbs liquid at a rate of 1.3% by volume, although in warmer liquids the expansion by volume can reach a rate of 2%. Although considerably less than most competitive non-metallic products, this expansion must be taken into account because it results in bore reduction as well as a slight increase in interference fit.
2)RUNNING CLEARANCE
Recommended running clearances for Thordon bearings,as well as all other non-metallic materials, are usually more generous than those specified for metallic bearings.
Running clearance is necessary for the establishment of a satisfactory liquid lubricant film. It also includes a margin of safety to allow for bore reduction as a result of frictional heating of the bearing during operation. There are different diametrical running clearance requirements for industrial and marine applications. Diametrical running clearance is the total difference in dimension between the final installed inside diameter of the bearing after accounting for the effects of temperature and water absorption, and the outside diameter of the shaft

Both of which in your case could lead to tightening of the bearing over time with heat and possibly trapped salt in the bearing leading to the stiffness, these deposits over time become rock hard and will not wash out, dismantling and honing is normally the only redress.

Cheers Steve

[Ivansgarage]

Cylinder Hone 7 bucks auto parts stores.

[CruiseEasy]

Originally Posted by Ivansgarage

Cylinder Hone 7 bucks auto parts stores.

Great for metal bushings but good luck honing Delrin or similar if you need to remove material. Pull them if you can and send them to me with specs required and return postage. I'll turn them on the lathe for you.

[MBWhite]

I hate to suggest to someone else to do a lot of tedious and unnecessary work, but I would strongly suggest pulling the shaft and doing a proper inspection right now as this is about the best scenario for doing so at the moment. You do not want to have to do this with the boat in the water and this way you can actually see where the problem is, easily.

Did the rudder get hit by an errant forklift or tractor in the past 3 years and crack a bushing? Most likely not but it will take a visual inspection to tell and you can also roll the rudder shaft on a flat surface like a kitchen counter and check for any bends. My phobia is having some sort of physical damage or failure that re-seats itself and acts normally until you are in a tricky situation and then goes completely. With a 2.5" ID, if the bearing checks out you can just make some extra clearance with a half round file and put everything back and rest assured it won't give you any more issues.

[hpeer]

33' steel boat. Similar issue. Wheel steering.

A bushing/bearing the wheel shat rode in seized while on the hard. In my case it was not the bearing but the aluminum holder it sat in. The holder corroded and squeezed the bearing tight on the shaft. It happen d once before and I was able to work it loose, not this time.

Went to a plastics machine shop with the bits and they made me a new bushing. $40.

[Terra Nova]

Pull the rudder, measure the bearings and shafts, and then determine how to proceed. Some of the steel parts may have swollen with rust. The bearings likewise have swollen with moisture. Refit as required.

[capt jgw]

Is there a stuffing box where the shaft enters the hull? I had one of those seize to the shaft once, and when I turned the wheel it twisted the hose connecting the box to the hull. Only a matter of time before the hose would split and sink the boat. Some penetrating oil and brute force got the box unstuck so I could replace it.

[Djarraluda]

Just do not ignore it. I did when I bought my first boat, enjoyed the degree of self steering it gave, but.....
Fortunately it was a transom hung rudder and when the pintle failed 2 weeks later, I could secure it. Lesson learnt.
If it ain't right, that means something is wrong
Roger

[Puffinclub]

Many thanks for the replies..all useful information!
I will dismantle the shaft ..I expect to find that the rudder trunk has rusted against the bearing... forcing the (soft and flexible) bearing against the rudder shaft...Makes sense to me. Thanks all!

[Puffinclub]

I dismantled the shaft and... indeed the lower bearing had been compressed onto the shaft by the force of rust forming between the bearing and the steel trunk. The rust was working its way up from the bottom of the trunk, which is below the waterline. The rusting really takes off once this area is exposed to air...for 3 years in my case.

I have reamed out the rust, painted with Novorex, and will reassemble tomorrow. However I am bound to have this problem again. The ultimate solution is a stainless steel trunk. In the meantime I am thinking I should silicone seal the bottom of the rudder shaft when the boat is stored ashore and pour some fish oil down to keep this area from rusting.