SM "C" drive oil and seals and wear bearing

Mike Ondra

We just hauled Aletes SM#240 for other reasons and considered changing "C"
drive oil and seals. Checking the log is has been only 240 hrs since last
changed and the oil in the reservoir looked fine. We believe the recommended
service interval for this is 800 hours so we did not proceed with the task.

However, several questions arose in this decision.

1) When there is water infiltration and the oil begins to turn milky,
does this show up in the reservoir? Does the oil actually circulate, or is
it just a visual verification of the level of oil supply? (There is a small
return hose coming in the top of the reservoir seemingly to return oil.)

2) If milky in the reservoir, clearly it is time to change oil and
seals even if earlier than 800 hours. However, if after 800 hours and the
oil is still good, why change the oil? If the seals are working well, could
it be 1000 or more hours between service? Perhaps it was 800 hours with the
2 seal configuration and the 3 seal configuration lasts a lot longer? I
wouldn't think there would be temperature degradation of the oil.

3) We have 3 brass shaft wear bearings (one installed and 2 spare). All
have been used and reused at one time or another. None show the kind of wear
indicated in photo postings. None have resulted in intrusion of water. (We
use 45x65x8 CRW1 R nitrile seals from SKF @ $6.04 ea. always installed 1 to
oil, 2 to water). The worst wear we see on any of them is a tiny score line
presumably where the seal lip touches the wear bearing. Are we just lucky or
does this seal system typically perform well and give long life?

Comments always welcome.

Mike Ondra

Aletes SM#240

Sent: Friday, September 26, 2014 2:08 PM
Subject: [Amel Yacht Owners] Prop shaft wear bushing alternatives and seals
and sourcing alternatives

I know that some very experienced people have suggested changing the prop
shaft wear bushings to stainless, or using a stainless sleeve, and/or some
other method. There are probably 6 unproven theories on this issue. I think
it all started because some of us believe that Amel overcharges for the wear
bushing (and they probably do). Then, of course, the theories about changing
the Amel-suggested orientation of the oil/water seals that fit on the wear
bushing. Then, additionally, various other sources of the seals, and O rings
in the place of springs...yada, yada, yada...I am getting a headache
remembering all of this stuff.

For what it is worth, I think that Amel has much more experience with this
than any one Amel owner, and certainly more than me.

I am sorry if I disagree with some of you, who, by the way, I respect
immensely...BUT, haulouts and C Drives are for too expensive for me to start
diddling with the small stuff. I am sticking with Amel for these parts. I
could not sleep at night if I started playing Russian Roulette.

I hope I haven't ruffled too many feathers, but I just had to say this...I
promise, I will not say it again.


BeBe 387

On Fri, Sep 26, 2014 at 5:51 PM, [amelyachtowners]
<> wrote:

This summer we had water in the drive-oil (milky) so we hauled and changed
the sealings. We found out that there was a steel wearing ring and not the
brass ring from Amel. When the seals have been changed last haul-out only
the sealings have been changed, according to the "professional" there is
nothing else to do. Now I learned that the wearing ring should be changed
always when the seals are changed, it is an inexpensive item from Amel
(compared to an extra haul-out)

I uploaded some fotos to show how the (steel) wearing ring looks at end of

Th wearing ring is fixed to the shaft and the outer surface is next to the
three seals.

fair winds,

tadeja and herbert,
KALI MERA, SN 120, Kusadasi

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