Mark, indeed there were some
scratches on the plastic shaft. Will gently sand them out,
measure, and go with the 29mm seal.
Thanks for the insight!
Seems like a Amel mini-rendezvous may
be happening at the Annapolis Boat Show. Might you be
coming up? We plan on being there Thursday and Friday.
Would be great to meet.
Rock Hall, MD
<main@AmelYachtOwners.groups.io> On Behalf
Of Mark McGovern
Sent: Sunday, September 1, 2019 4:26 PM
Subject: Re: [AmelYachtOwners] [Amel Yacht Owners]
New size for Bow Thruster seal
I did my first bowthruster service this past winter and
used a 29x42x8 seal. It was a tight fit but it works.
The seal I replaced was also a 29mm ID seal. There was no
oil leaking from the seal while the boat was sitting on
the hard after the service and the oil is still clear -
not the "cafe creme" looking mixture of oil and water.
However, when I disassembled the unit to replace the
bearings (preventatively) I could feel a small groove in
the shaft where the previous seal sat. The shaft was also
discolored with a brown-ish stain at that point:
I consulted with Olivier Beaute and he told me that if I
felt any kind of groove that I should try to gently sand
it out with 600 grit sandpaper and water. He also said
that if I could NOT feel anything that I should NOT sand
it but just clean it as sanding the shaft comes with it's
own risks. I measured the shaft OD at the point in the
shaft where the oil seal sits with calipers and found that
it was about 29.5mm so there was plenty of "meat" on the
shaft for a 29mm ID oil seal so I wet-sanded the shaft
smooth, re-assembled everything and so far, so good.
However, a 30mm ID seal would have likely resulting in a
static oil leak like you have and certainly would have
allowed water to enter the bowthruster during use
Consider taking the entire bowthruster shaft apart,
measure the shaft OD and inspect it for any damage where
the oil seal sits. Also check the OD for any damage as
SM #440 Cara
Deale, MD USA