Cutless bearing is one of those things that will need to be replaced sooner or later if you use your boat.
With the proper tools this job can be easy and you might want to give it a try. If you do not have the right tools it can be difficult or even develop to a nightmare.
The cutless bearing on the HR 43 is glued into a stern tube made of fiberglass (GRP=Glas Reinforced Plastic). The reason for using a stern tube in fiberglass, instead of the more traditional metal tube is to avoid bonding problems between metal and GRP. Laminating against metal is always a challenge, and poor bonding is not uncommon. Another advantage with a stern tube in fiberglass is that it will not be damaged by corrosion.
To get the cutless bearing out, you need either to remove the shaft, and then cut the bearing in two halves, or pull it out with help of a puller. There are two different types cutless removal tools that can be used. If you continue reading you will find pictures of both types.
On the HR 43 you can pull the shaft, with the bearing in place. With the bearing in place, it will be tight and you might scratch the skeg, or in worse case have to grind a bit on the skeg or rudder to pull the shaft. It will still be easier to make a GRP repair in the rudder, then having to drop the rudder!
“N.B. If you have a factory installed rope cutter, Ambassador Stripper and a fiberglass tube you need to use the “cork screw puller” or pulling the shaft, as there is an outer sleeve in brass on the outside of the stern tube. “
We had heard a rumbling noise when doing the Italian Tuning, and the play in the cutless bearing was confirmed after a visual inspection when the boat came out of the water at Artemis Boat Yard.
How long does the cutless bearing last?
This last cutless bearing has been in service for approx. 1300 hours. This is the second time we change the bearing. The first cutless bearing lasted only 350 hours! It is impossible to say how long the cutless bearing will last, as there are many factors involved. Engine hours, water quality, aligning, type of propeller, and how you are running your engine are all factors that matter. A fishing line that wraps around the shaft can easily destroy the cutless bearing in a short time.
A friend reported his bearing was destroyed after the boat had been sitting still in the Marina in Panama for a little bit more than one month. When he was moving the boat 200 m from the slip to the travel lift he could hear a terrible noise from the bearing when the shaft was turning. When the boat was out of the water, it was obvious that the cutless bearing was damaged from marine growth inside the bearing. The rubber was totally destroyed after the short trip from the slip to the travel lift.
How much play in the cutless bearing is acceptable?
That is equally difficult to answer. All cutlass bearings show a play after a while. I have seen some numbers how much play that is acceptable, but never been able to figure out a reliable way to measure the play. For me it is just a matter of feel and experience. My advice is, do not change the bearing only because you can see a play. I have seen a play in this last bearing already after the second season! The play increased season by season, but it took another six years until I started to hear rumbling noise. If you can not hear a rumbling noise when motoring hard, the bearing is probably O.K. It helps if you have developed you “engine ear” and can hear the difference between normal noise and a worn cutlass bearing. Do the Italian tuning regularly and you will soon learn what is normal. If you have never been running your engine flat-out ( 100% ), it will be very difficult to decide what is coming from a worn cutless and what is just noise. Running the engine on full RPM is noisy as you most probably will have lot´s of cavitation.
Replacing cutless bearing first time after 350 hours.
The first time I changed the cutlass bearing, it was installed flush with the stern tube which makes the change much more difficult. Many HR:s have the bearing installed flush.
Hallberg-Rassy have later changed the installation. On recent boats the bearing is not installed flush which makes it easier to change.
First it looked impossible to change the bearing, without pulling the shaft. But instead of pulling the shaft, I removed approx. 20 mm of the stern tube. I used a saw and a chisel for the work. When 20 mm of the cutless bearing was free, I could use a one meter long pipe wrench around the bearing. One person on the wrench, and one hammering trying to drive the bearing out. The bearing was moving a little bit sideways but refused to come out. After 2 hours we gave up, as I was afraid damaging the stern tube.
In the workshop I did find a special built puller, with a sliding hammer. It was not the ideal tool as it was made for a 40 mm shaft and the HR 43 has a 35 mm shaft. But With some difficulties it was possible to pull the bearing with this puller. After that experience, I ordered an improved model of the puller from a local workshop. Today this puller can be ordered from Hallberg-Rassy Parts , and can be used on both 35 and 40 mm shafts.
When I installed the new bearing I did not stick it in flush with the stern tube! I left 27 mm of the bearing protruding out of the stern tube. (20 mm would had been enough to get a firm grip with the puller) I glued the bearing with epoxy and used two lock screws.
It was a bit exiting to see if it would be easier changing the cutless bearing this second time!
Replacing cutless bearing second time after 1300 hours:
Bearing before operation starts.
I removed the epoxy filler that was covering the stern tube and the two lock screws. No fiberglass had to be removed this second time.
The old epoxy filler removed. No G.R.P. removed this second time.
Then I attached the puller and made marks in the old bearing. Removed the puller and drilled holes for the bolts in the old bearing.
Holes drilled in the cutlass bearing for the puller
Then it is just to attach the puller, tighten the bolts and start hammering.
Puller attached to the bearing and then using the sliding hammer
Protection for your ears is recommended when using the sliding hammer!
Puller with old bearing. (This puller works both for 35 & 40 mm shaft.
The whole operation, removing the old bearing took less than 20 minutes!
It actually took longer to remove the propeller as it was sitting quiet hard. You do need a good puller to remove the propeller! If the propeller does not move try knocking on the hub with a hammer. In worse case you might need to heat up the propeller hub.
When the old bearing is out, it is just to check the condition of the propeller shaft before replacing the bearing. In our case, the propeller shaft was damaged by crevice corrosion, and need to be replaced. It was a surprise, having in mind that the original shaft is made of a high quality steel.
After some research I decided to replace it with a shaft in Duplex Steel (1.4462) same steel as used in Chromox Duplex Anchor Chain. This steel has even better resistance against pitting corrosion. Spiros at VETUS Greece Piraeus provided excellent service and delivered a new shaft to Leros in less than 2 weeks, which will installed in the spring.
Crevice corrosion damage between shaft and cutless bearing
Alternative puller that would work on boats with stern tube in fiberglass or metal.
Here some pictures on a another type of puller that would work on most type of cutless bearings, including HR:s with a factory installed Ambassador Stripper on a fiberglass tube or a regular stern tube in metal. This puller is designed to cut away the rubber inside the bearing, and at the same time cut a thread in the bronze part of the bearing. When the thread is deep enough, and the tool firmly screwed in to the bearing it can pulled out.
I have never used this tool myself, and have heard both good and bad reports. Some reports said it was difficult to get a good grip in the bearing. I would think this might be caused if the tool is not screwed in deep enough.
When my friend had to change his cutless bearing in Lisbon, I made a simple sketch of the tool on a piece of paper. A local workshop in Portugal was able to manufacture the tool that you see below.
Overseas 40, with a standard metal stern tube. Many Hallberg-Rassy have exactly the same construction.
Puller cuts a thread in the cutlass bearing. At the same time it cut away the rubber inside the bearing.
Puller with handle over the bolt that sets against the prop. shaft.
Finally the bearing comes out after some heat was applied on the bearing house.
In retrospect, I think a sliding hammer function instead of the “puller bolt” would had been better alternative.
The advantage using a puller is that there is less risk damaging the stern tube.
A friends, friend recently left the job to change cutless bearing to a boat yard with a good reputation. It was the same construction as on the Oversea 40 above. Unfortunately the stern tube came loose when they tried unscrewing the house from the stern tube.
Off course the boat yard would not take any responsibility as the problem originated from poor bonding between the stern tube in metal and the filler/laminate. It became a very expensive repair as the fuel tank had to be lifted and access holes had to be made. I´m sure a puller would have saved a lot of money in this case. Replacing the stern tube is a big job, a job you want to avoid to any price.
Another pulling tool that would work is the one that Nilo designed. It is a mix between the tools I described above. I´m sure it will work good.
Download Nilos drawing for the puller here: Cutlass bearing removal tool
The puller with sliding hammer is an excellent tool that can save a lot of time and work.
Crevice corrosion is more likely to take place when the boat is sitting still in waters with high temperatures and high salinity. As long as the boat is moving, you get water circulation in to the cutless bearing and crevice corrosion should not be a problem. The last 3 years we have never been sitting still more than a week, with exception for 4 weeks in Pireus this summer. It is possible that it was the warm and dirty water in Pireus started the corrosion. A more likely explanation is that it has been an ongoing process over several years.
If you have your boat in the water it is recommended that you turn the shaft every 2 weeks to avoid crevice corrosion.
Keeping the propeller shaft free from marine growth is also important to avoid crevice or pitting corrosion. I could see pitting corrosion under the barnacles. Have to admit I have not been so meticulous in removing all scaling from the shaft when out of the water.
Well, after reading this far you might not have energy to read part two?