Category: Rudder Repair

Rudder removal and repair – part 2

The sailing season 2018 has almost begun and it is time for an update on the ongoing repairs and what has been going on over the past 3 months:

Making a new pin on the lathe

Back in Germany I reworked the parts of the lower bearing and made a new pin. I used “Essmatur” for the Pin as proposed by Hallberg Rassy in their repair instruction. It took me some time to find out what “Essmatur” was. It is an older Swedish designation for a dezincification resistant brass alloy (DZR brass) much easier to obtain if you ask for CW602N which is essentially a leaded arsenical brass (CuZn36Pb2As). The arsenic provides the dezincification resistance and the alloy is supposed to be suited for applications in seawater environments.

Some dimensions:

• Original bore size: 35mm
• Original pin diameter: 34.5mm
• Max wear inside the bore: at the location where the pin ended in the upper part of the bearing with the diameter of the hole being 35.8 mm
• Max wear of the pin: 33mm diameter in the middle
• New bore size after rework: 36mm
• New pin diameter: 35.6mm

Careful alignment of the hinge parts under the drilling machine ensured that the axis of the enlarged opening remained perpendicular to the contact surface.

This is the tool that was used to rework the holes.

My friend and colleague Robert provided some professional help which was highly appreciated!

The result couldn’t be any better.

I also made myself some plates (these were made out of Tin Bronze, CuSn12) which I will need for aligning and fixing the position of the bearing to the skeg (the old alignment plates can be seen on the left side of the picture).

Back in Greece I tried putting everything back together. Hallberg Rassy says in the instruction, that a tube must be used for the alignment of the lower bearing if it was removed, in order to get it in line with the shaft axis. I used the rudder shaft upside down together with an adaptor which fitted onto the rudder shaft on one side (40mm) and the (enlarged) hole of the bearing on the other side (36mm).

After some experimenting and a lot of head scratching, I finally had to accept that I would never get the parts aligned as they should be because when they were put together at Hallber Rassy, the lower bearing axis must not have been in line with the rudder shaft axis, but off set by about 5mm. It is of course likely that this is not the first time the assembly is being taken apart, and was not put together properly again.

The misalignment is obvious

Anyway, some comfort can be derived from the fact that the assembly did work flawlessly for 35 years until I took it apart. I am confident though, that I will find the right position for the alignment plates that I made and get everything back in a proper working order, but first I have to apply some layers of epoxy primer for osmosis prevention since the area is perfectly accessible with the rudder removed.

….more on “Rudder removal and repair – Part 3”

Rudder removal and repair – part 1

It is done. Matilda’s rudder is removed. I must admit that although I had read almost everything I could find on the web about accomplishing this task, it has not been a straight forward operation.  There is also a description from Hallberg Rassy which gives confidence but some people managed to bend the thread at the rudder shaft end or needed an electric file to remove the locking key step by step as the shaft was coming out of the upper bearing together with the locking key. Since it does not fit into the rudder shaft tube it has to be removed somehow.

Here is Matilda’s rudder removal and repair story:

The task starts with removing the putty all around the bearings in order to free them and get access to the screws and the nut at the shaft end. This has been described many times but it is a different thing reading about it or doing it.  You normally don’t “treat” your boat with a hammer and a chisel and it took me some time to get started. Once started, this task is quite easy. You only have to be careful not to damage too much of the gelcoat (although repairing it later is not an issue).

The nut at the end of the rudder shaft comes free as the polyester putty goes.

Some people reported that there was a washer under the nut. There isn’t any on mine.

Not sure what putty was used here… epoxy?

The area underneath the upper hinge at the port and starboard side of the rudder were also wet and I decided to remove the putty wherever it wasn’t too difficult.

The next thing you have to do is to push the shaft out of the upper bearing. What is needed here is a custom made special gear puller that fits around the upper bearing.  I used a pair of wedges for this as described in Hallberg Rassy’s instructions.  After I had positioned them carefully perpendicular to the rudder shaft axis, the shaft came loose easier than I had expected. Unfortunately, the locking key was stuck to the shaft and was coming out together with it. I have used the locking key from the steering quadrant which I placed between the rudder shaft key and the rudder tube in order to hold it in place whilst the shaft was forced upwards. This was the most painful part of the operation. I used some heavy duty wedges (which were at least 5 times the size of the ones I had prepared for the job and I also used some posts which I had to put into the bearing as its end with the nut was disappearing into it. I was reluctant when I started hammering on the wedges because there is quite some force applied to the rudder shaft tube which pushes it up into the boat’s hull but since I had to repair a little leakage there anyway, I became more courageous with every stroke of the hammer, especially when I saw that the rudder shaft was moving but the locking key was hold back against the tube and the tube itself was steady as a rock. I took a while but finally the rudder shaft, the locking key and the upper bearing were separated and the rudder could be removed.

The smaller wedges were carefully positioned perpendicular to the axis of the shaft.

The rudder quadrant and the autopilot gear had to be removed prior to the operation of course.

The rudder shaft with the stuffing box packing gland at the left side of the picture and the nut on the right side

Good news is that with the exception of some gelcoat scratches here and there, nothing was damaged.

The part of the lower bearing that was mounted to the skeg was not very easy to remove because it was bent around the skeg and needed to be opened to get it out. It won’t be easy to put it back on place again as it will need careful adjustment in order to be in line with the ruder shaft tube axis.

Four 3mm thick bronze plates (approx. 15 mm X 20 mm) were placed under the lower hinge (arrow shows location) on both sides at the skeg most likely for adjustment and fixation. (correction June 27th 2018: the alignment plates were mounted only on the side shown on the above picture. More pictures and information on the post from June the 27th) 

The lower bearing can now be removed completely.

The parts comprising the lower bearing look better than I expected and would probably have done their job for at least another 35 years.

The play in the lower bearing was about 5 mm (compare two pictures above).

The bores are still round but don’t have the same diameter all the way though anymore.

The pin showing some abrasion especially in the middle section where the hinge parts meet.

I will rework the parts back in Germany where I have the luck to have access to a nice little machine shop and can count on the help of my very experienced colleague and friend Robert who had also joined me on the 3rd leg from Lisbon to Gibraltar on my trip around Europe.