How to service rudder shaft?

alex · Post by **alex** » Thu Mar 04, 2010 22:28 pm

Hello,

How to service rudder shaft? It has developed a slight backlash recently.

Alex

harald · Post by **harald** » Thu Mar 04, 2010 22:53 pm

You'd have to start with digging a hole under the rudderblade in order to get it out. I suspect that you're in need of new bushings, and these won't come out without dropping the rudder.

Remove the tiller, that's one long bolt.

There are two allen-key bolts that hold the upper mounting collar. These could preferably be treated with CRC or WD40 long before the actual operation, because they can be stuck. Remove the bolts (threaded pins actually), and the rudder should drop. It weighs over 40 kg so you should have a companion or a hoist of some sort so you don't drop it too hard.

After this the bushings can be pushed out. Some have used a pipe, but beware not to be too violent or the tube laminated to the hull could become loose. This means even more work.

There are drawings of the bushings in our wiki;

http://www.fe83.org/wiki/index.php/Per%C3%A4sinlaakeri

You can get some clues by gleaning in our gallery as well;

http://www.fe83.org/gallery/view_album. ... e=album414

http://www.fe83.org/gallery/view_album. ... e=album417

http://www.fe83.org/gallery/view_album. ... me=Perasin

Was it protoshop in Otaniemi that was able to make these bushings out of POM?

Personally, I wouldn't bother the backlash. We've had it for years and personally I rather like the easy movement of the tiller and I just don't want to risk having a binding bushing in there.

http://www.fe83.org/wiki/index.php/Per% ... en_korjaus

alex · Post by **alex** » Thu Mar 04, 2010 23:30 pm

harald wrote:You'd have to start with digging a hole under the rudderblade in order to get it out.

How deep shall that hole be?

I am already tired removing snow...

harald wrote:Was it protoshop in Otaniemi

Yes, I am familiar with the Protoshop.

harald wrote:Personally, I wouldn't bother the backlash. We've had it for years and personally I rather like the easy movement of the tiller and I just don't want to risk having a binding bushing in there.

I like how it sounds. The backlash is very little, I will consider leaving it as it is.

Another thing is last summer there were traces of lubrication around top of the rudder shaft after we were getting very many splashes in fresh weather during a long day. It looked like sea water washed out some lubrication out of the shaft or so. Is there lubrication there? Not necessarily if there are plastic bushings. Where could that oil come from then? I wanted to have a look when I get the rudder removed, but it's even more important to understand what it was if I am not taking the rudder away.

Petri · Post by **Petri** » Fri Mar 05, 2010 00:10 am

alex wrote:
harald wrote:You'd have to start with digging a hole under the rudderblade in order to get it out.
How deep shall that hole be? I am already tired removing snow...

~1 m is sufficient, I reckon 70cm is near the minimum. I mean, it is lot easier to dig a hole deep enough at the first time than try to remove the rudder only to see that the hole is too shallow.

harald · Post by **harald** » Fri Mar 05, 2010 00:18 am

And the ground is frozen...

I'm just guessing, but the previous owner has probably thought it to be a great idea to lube the shaft a little. Strictly it shouldn't be needed. It could be some metal-oxide, perhaps?

mihor · Post by **mihor** » Fri Mar 05, 2010 13:52 pm

alex wrote:How deep shall that hole be? I am already tired removing snow...

The depth of the hole depends on how high the boat is sitting from the ground. The overall length of the rudder is 190cm (from the top of the axel to the bottom of the blade). So the hole needs to be deep enough to provide a 190cm clearance measured from the hull to the bottom of the hole.

VVille · Post by **VVille** » Fri Mar 05, 2010 18:47 pm

Measure first if you have to dig a hole, and if it proves to be necessary, do it preferably when the ground ain't frozen anymore. Of course you can get new bushings already, the removal and installation won't take very long if you have someone helping you. It will be a royal pain in the arse to dig a 70cm hole in frozen ground, unless you have some dynamite, and that may bring some other problems...

In best case you may have the boats winter cradle sitting a bit higher from the ground, and thus you don't need a hole at all. We have the cradle on wooden blocks (because we put the boat in water with this nice cart system of OV), which are about 40-50cm high, and we didn't need any digging to get the rudder off.

Are you sure that the backlash is from bearings and not from the outer shaft (vannasputki) on the hull? Our outer shaft is bit loose on the upper end, because the movement limiter broke and thus the outer shaft, which is only bolted to the deck, carved the bolt holes bit bigger and started to move about. We are going to laminate the upper end into the hull to eliminate the backlash and to make sure that this won't develop to anything more serious. The construction of the upper end is poorly desingned as it is, because that the bolts which hold the upper end act also as the movement limiter and get some sideways hits from that. I would recommend everyone to check that the bolts are tightened properly to prevent any movement.

Ville Valtonen

Olli · Post by **Olli** » Fri Mar 05, 2010 20:27 pm

VVille wrote:Are you sure that the backlash is from bearings and not from the outer shaft (vannasputki) on the hull? Our outer shaft is bit loose on the upper end, because the movement limiter broke and thus the outer shaft, which is only bolted to the deck, carved the bolt holes bit bigger and started to move about. We are going to laminate the upper end into the hull to eliminate the backlash and to make sure that this won't develop to anything more serious. The construction of the upper end is poorly desingned as it is, because that the bolts which hold the upper end act also as the movement limiter and get some sideways hits from that. I would recommend everyone to check that the bolts are tightened properly to prevent any movement.

Sanakirja.org translates vannasputki to stern tube. It's true that the original solution to fix this tube to deck is not strong enough. Anyway, I think that laminating is not necessary. I replaced the original bolts with allen bolts that can be tightened to a lot higher torque, and used large washers and nylock nuts under the deck. This has worked now several years without having to tighten the bolts before every trip.

However, if the problem is in the rudder shaft bearings, I recommend waiting until fall, it's easier to dig the hole...