Re: Bow Thruster maintenance fail

James Alton


   Bill knows his seals.  IMO a lot of the sealing with the bow thruster in the up position is done by the black foam donut seals that are in compression.  These take a set when compressed over time and lose some of their spring back so do not seal as well.  I think that the amount of time that this seal is in compression has a lot to do with when these seals need to be replaced and also how well they seal when you need them.  For myself, one thing that I do is to leave the bow thruster unlocked when the boat is dockside or in storage and save the compressive qualities of the seals for the challenging times such as beating to windward in big seas.  Not pinning the bow thruster of course introduces a new risk in that it is all on the lifting mechanism and the cable to keep the bow thruster up so I understand the reason for the locking pin so.  It seems that it is seldom the case with boats that an answer is  black and white.  

James Alton
Maramu #220
Marmaris, Turkey

-----Original Message-----
From: Steve Bell s/y Dusk SM378 via <stevect@...>
Sent: Thu, Jun 16, 2022 11:46 am
Subject: Re: [AmelYachtOwners] Bow Thruster maintenance fail

Hi All.
        I replaced the seals on my bow thruster approx 2 years ago same process apart from struggling to find the stews as matured it was an easy process.
On Bill,s recommendation at the time we ensured the replacement seal had the stainless steel spring as the old seal spring showed signs was badly rusting.

The one question I have is the time between  replacing the seals we only use the bow thruster when entering a marina and with covid over the past two years our sailing time was curtailed somewhat.

How often do you replace the seals  every 2 years or  dependant on hours used.?


S/v Dusk #378

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