Re: [Amel] Re: bow thruster service

Ian Shepherd


you are right. It's design is far from satisfactory. The bow thruster on
my first SM shed propellers 6 times in 27 months, and due to an
oversight in design, it actually sank my boat when the tube failed and
the whole unit fell out of the boat. On my second SM, the nylon screws
have been made thicker, and happily I have not lost a single prop in 7
years. The anti torque modification has cured the tube failure problem,
together with the whole unit now being enclosed in a water tight
compartment. However, the water ingress and corrosion continued to be a
serious problem and I decided to make the whole unit better as follows:

I had a thin stainless sleeve manufactured so that the lip seal could
run on a proper surface and not on the somewhat rough texture of the
shaft itself. I since heard that you can buy stainless sleeves off the
shelf that will shrink onto the shaft. Check this site for posts on this.

I use seals that are fitted with a stainless spring. They last longer.

I replaced all of the open ball race bearings with sealed bearings. This
does mean that you can no longer pour oil in from the top if you use a
sealed bearing on the vertical drive shaft. To overcome this I removed
the back plate of the bow thruster and packed the whole unit with water
proof grease. I also filled the area between the outer shaft bearing and
the lip seal with some grease, but not too much else you will not be
able to tap the seal fully into its housing. Grease will not disappear
like 90 SAE oil.

It's been that way now for over a year now with some 4000 miles sailed
in that time, and has run perfectly. It also runs more smoothly. I have
not yet removed it and taken it apart to see whether any water has got
in as there has been no noticeable change in the noise which is a good
clue that the gears are running in sea water and not lubricant.

When I looked over an Amel 54 shortly after it first appeared, I noticed
that it was fitted with a bought in thruster made by Schleiper. Maybe
Amel have finally admitted that their home made unit did not meet their
usually high standards.

Ian Shepherd SM 414 Crusader

On 06/03/2011 07:15, wrote:

The bearing are corroded it is almost IMPOSSIBLE to make the bow
thruster tight and more or less sea water pollute the oil
This AMEL bow thruster is a technical sum of non sens, approximations
and many many different problems for the owners ....
I would like to know how many SM have a tight bow thruster

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