Replacement of thrust bearing on IP 485

Hello dear Island Packet crowd,

On our "Calypso" - hull no. 48 - we have had to replace the Python drive P 110T two years ago due to wear.
Now it seems that the thrust bearing needs replacement too. Has anyone had any experience with that?
I have tried to measure the nut-size, which keeps the shaft locked in the bearing - it seems like 44 mm... difficult to measure
inside the bearing chassis. Could of course not be metric...
Also - is that whole procedure possible without removal of the rudder? In order to remove the thrust bearing I will have to move the shaft aft, so would there be enough room?

Thanks a lot for an answer folks!!! At present we are unable to access our boat in the Canary Islands due to the virus, but we are hoping...

All the best and good health to y'all

Tom Hehz

Hi Tom,
Just a few questions regarding this thrust bearing query as I need to do the same job on my IP485 when I get back to her.
Did you change the bearing and how did it go?
Did the shaft withdraw enough without removing the rudder?
Is the bearing shown in your picture the correct bearing?
Any answers appreciated.
Alan

and - what was the nut size please? was 44mm correct?

Hi Alan, the job is done and I have infos and pictures for you. Just a little patience, am on the go...
Greets Tom

Hello again Alan,
here are some pictures for you. They show amongst others the support I made of wood to support the shaft during extraction, and also the extraction tool I had made by a blacksmith
in Germany, which came in very handy. Without that I could not have extracted the shaft from the clamp. Even then, as I tried to turn the bolt against the end of the shaft to drive it out,
the friction was too great. A strong plastic bottle cap placed in between bolt and shaft helped...
Once the shaft was freed I could move it back and yes - at the end I had a gap of about 2 cm to the rudder - so - no need to remove the rudder fortunately.
The size of the nut was a 46 and not 44 as I had guessed.
I had the bearing replaced in a car workshop which apparently was no problem.
The reinstallation worked out of course much easier
I do have a question for you: What kind of tool do you use to refurbish the stuffing box? It's a real b... to access! No space at all. Hammer and chisel are a scary option.
Would be nice to get some info on that!
Good luck with your job at hand and hope to hear from you soon,

greets from the Canaries,

Tom

  

Hello Tom,
Thank you very much for all this information, it is most helpful and very much appreciated. Sorry but I still have one or two questions.

But first regarding your question about the stuffing box nuts, I did post a reply to this a few days ago and here it is again in case you cannot see it -
[Alan Broadbridge Hello Ton, Yes I have had the pleasure of that job, I tried with various adjustable spanners and clamps but eventually I made a tool. I purchased a ring spanner, it is a very large one and an unusual size (I can maybe find the size if you dont know it) then when it arrived I cut out a piece of the circle just big enough to clear the shaft, this obviously weakens the ring spanner but it was a very heavy duty tool and seemed to work fine as it is not actually torqued up very tight. The job was then much easier, 2 ring spanners would be even better but they are expensive and also there is a problem with the two hexagonal nuts being right next to each other. One problem is that if you use 2 ring spanners then the spanner shafts might interfere with each other (this depends on the exact design of the spanner i.e. straight or cranked etc.) but the more important issue is that if the two adjacent hexagons dont line up then of course you wont get the ring spanner onto or off the further hexagon. So probably best with just one ring spanner and a “something” Show less
3 days ago]

Further to this, I have seen mentioned the use of a "Crows foot ring spanner" this is a standard tool that can be purchased and it might do the job. But be careful, firstly it is important that it is a ring spanner with 12 flats (not 6) because there is not enough room for the spanner to turn 1/6 of a turn. Also if you find one that looks okay make sure that the cutout (the open section) is large enough to fit over the prop shaft. If you do not know or cannot measure the size of the nuts please ask me, it might take a few days but I can hopefully find the invoice for the spanner that I purchased.

Regarding the thrust bearing job, our boat is in Fiji and we are home in the UK, so we need to try to take out everything to do this job as there is limited facilities and supplies available in Fiji.
The useful extraction tool- I presume that it bolts to 4 (of the 6) holes in the bearing flange? - Do you know the P.C.D. (Pitch Circle Diameter) of these holes and also bolt size and thread please?
Your original post shows a large bearing and the reference number appears to be "3216-2RS" which has dimensions 80mm I.D x 140mm O.D x 44.4mm - Was this the correct bearing please.
Best wishes
Alan

Hi again Alan,
in reply to your question - yes the bearing 3216-2RS is the correct one.
I purchased it from a company called Krahwinkel in Germany (Google) who is a specialist on Python Drives. Around 200 Euros...
He will also be able to quote the correct P.C.D. for you. He did it for me but the documents on that are back home in Germany and we are in the Canaries...
In the extractor you will need a thread cut for the central bolt which is a DIN961 bolt M20x1.5x100 fine thread. The four bolts on the P.C.D. are DIN933 M10x45 with some extra nuts to serve as spacers. The holes on the P.C.D. don't need a thread, just need to be big enough...
As concerns the stuffing box- I also had a tool with a slot for the shaft made - still very difficult because I didn't get the exact size. Do you recall the nut size of the stuffing box?
That's all I think for now, greetings to the UK
Tom

Thank you again Tom, I will of course try to find the spanner size and will report.
Alan

Hi Tom,
I have found the invoice, the spanner that I used was an imperial size 2 7/16" (two and seven sixteenth inches) and it was a good tight fit.
Hope this is helpful.
Alan

Hi again Alan, thanks a lot for the spanner size. That’s approximately what I managed to measure in metric: 62.2 mm.
I‘try to get a slim spanner that fits.
For how long have you had your 485?
Greets Tom

Hi Tom, we have owned our 485 since 2018. Would be happy to contact you by email or WhatsApp etc. but don't really know how to share our details with you?
Alan

Hi Alan,
of course this is possible.
Here’s my email address:
This email address is being protected from spambots. You need JavaScript enabled to view it.
Then we can go via Wattsapp.
Greets Tom

Hi Tom,
I saw this and was curious how you knew that it was time to replace your python drive and thrust bearing? We have hull #47 so probably very similar to your boat on the timeline. Only 2200 hours on the engine but many miles sailed which keeps all those parts turning since we don't have a folding prop. Thanks for all the info and the pictures.

Hi Alan,
Calypso has hull number 48 and at the time of the bearing change approximately 1350 hrs on the meter. We operate her with a Variprop Df112. After a month’s stay in a marina we made a trip of roundabout 100Nm, after which I saw that a great part of the thrust bearing‘s grease had been expulsed and evenly distributed in the bilge. We drydocked Calypso thereafter and found strong barnacle growth on one of the prop blades. I suspect that caused an imbalance and caused vibrations which in turn caused the bearing to shed the grease. Hence my decision to change the bearing and from the on I dive down every 4 weeks to cleanse the prop (Scotch Brite...) Since then all is ok...