Cutlass bearing

Daydream believer

Well-known member
Joined
6 Oct 2012
Messages
19,974
Location
Southminster, essex
Visit site
My yacht has a sail drive so I have no experience of them since my last Stellas.
However, I have just bought a launch from the Royal Corinthian YC which I have bought for use by my sailing club to place moorings & general club duties etc.

The cutlass bearing seems to be a Manecraft Deep Sea seal by Norris but their site does not have details of it. There is clearly some misalignment, as when I leave the boat the seal leaks very badly. But if I gently rotate the shaft I can find a point where it slows to a tiny drip.
When the engine is running the plumber block seems to be shot so need replacing because at slow revs the Beta engine jumps about all over the place & the shaft moves violently from side to side. At higher revs it runs smooth with less vibration.I will deal with this later when we have finished laying our moorings in a months time. Currently it has just started to " graunch" badly as if running metal to metal, but we cannot spend time removing now as mooring holders need their moorings in otherwise the club cannot move the cruisers for the dinghies to park

What I would like to know is---is there is any adjustment on the bearing seal. There are a number of jubilee clips plus another around the shaft just in front of the rubber but it is round the shaft & does not seem to be doing anything.there is also a red label saying only remove in emergency Why? Can I tighten anything to stop the leak? there is a water hose leading to well above water line but no grease point

Any advice appreciated
 
Last edited:

pvb

Well-known member
Joined
16 May 2001
Messages
45,603
Location
UK East Coast
Visit site
The cutlass bearing seems to be a Manecraft Deep Sea seal by Norris but their site does not have details of it. There is clearly some misalignment, as when I leave the boat the seal leaks very badly. But if I gently rotate the shaft I can find a point where it slows to a tiny drip.

That isn't a cutlass bearing, it's a shaft seal. Take a look at http://www.deepseaseals.com/about/
 

Daverw

Well-known member
Joined
2 Nov 2016
Messages
2,742
Location
Humber
Visit site
Standard deep sea seal, the two clips on the rotary fix it to the shaft and also add some compression to the seal face, about 10mm compression is about right. The large red clip is to compres the stationary part on the shaft in the event of major failure of the seal face.
 

Bilgediver

Well-known member
Joined
6 Jun 2001
Messages
8,119
Location
Scotland
Visit site
If it was my boat I would split the shaft to gearbox coupling and check the shaft alignment. This might affect the rate of leakage . After realigning and securing the coupling then you will need to ensure you slide the shaft mounted section of the seal to the correct position to give the correct compression on the seal face. If you are in Edinburgh PM me
 

geem

Well-known member
Joined
27 Apr 2006
Messages
7,654
Location
Caribbean
Visit site
We have the same seal on our boat. They dont like longitudinal movement. Our plumber block has a split bush inside the bearing with a machined ridge. This matches a machined slot in the propshaft. This system locks the propshaft so there is virtually no longitudinal movement. We dont have any water ingress. The plumber block should take out all side to side movement even if it doesnt stop the longitudinal movement without the split bush arrangement. Sounds like a rebuild is neccessary.
 

Daydream believer

Well-known member
Joined
6 Oct 2012
Messages
19,974
Location
Southminster, essex
Visit site
If it was my boat I would split the shaft to gearbox coupling and check the shaft alignment. This might affect the rate of leakage . After realigning and securing the coupling then you will need to ensure you slide the shaft mounted section of the seal to the correct position to give the correct compression on the seal face. If you are in Edinburgh PM me

As I explained- i cannot take the boat out of the water until the moorings have been placed. Then I will strip the lot & look at it. I need a quick solution in the short term- if there is one!!!!!
But i do not quite see how one can align the seal any better with the shaft disconnected.
We have spoken to members of the old club that owned it & it seems that this boat has always had a shaft misalignment problem so this is not new.
 
Last edited:

Daydream believer

Well-known member
Joined
6 Oct 2012
Messages
19,974
Location
Southminster, essex
Visit site
We have the same seal on our boat. They dont like longitudinal movement. Our plumber block has a split bush inside the bearing with a machined ridge. This matches a machined slot in the propshaft. This system locks the propshaft so there is virtually no longitudinal movement. We dont have any water ingress. The plumber block should take out all side to side movement even if it doesnt stop the longitudinal movement without the split bush arrangement. Sounds like a rebuild is neccessary.

Thanks for posting
Interesting point. There is a bush, Possibly bronze, about 20mm deep & about 60 mm diam just spinning loose on the shaft just in front of the plumber block. It looks like it had 3 allen screws in it at one time, but they are no longer there.
from what you say, that suggests that at some time someone had it against the plumber block as some sort of stop to prevent the shaft moving back. I will investigate further. Although I suspect that it will grate against the housing of the block or the outer ring of the race. Perhaps not & the screws have dropped out although that seems odd. Perhaps it was tried & deemed unsatisfactory. Who knows?
But I will follow your point up & when I do remove the shaft I will consider machining a groove in it as you suggest. I can do that myself, so no problem

I
 

Daydream believer

Well-known member
Joined
6 Oct 2012
Messages
19,974
Location
Southminster, essex
Visit site
If it was my boat I would split the shaft to gearbox coupling and check the shaft alignment. This might affect the rate of leakage . After realigning and securing the coupling then you will need to ensure you slide the shaft mounted section of the seal to the correct position to give the correct compression on the seal face. If you are in Edinburgh PM me

As well as the engine coupling there is a plumber block mid length, so shaft could be aligned left, right, up, down.
Knowing that now would make no difference. Boat has to finish the job first.
 
Last edited:
Top