Let me try to help you with your questions. I did not design the bow
thruster, nor am I an engineer. I certainly cannot suggest intended
strategies, but I have some suggestions for you. I have used and
serviced it successfully and may be of some help.
1) The penetration through the hull is above the water line when at rest
in calm water.
2 a) The 2 closed cell foam rings on the shaft outside the hull are
compressed against the hull opening when the bow thruster is fully up
and the safety pin is in place…It is important to pull on the wire
bringing the thruster high enough to insert the pin each time you go
sailing (you will also have to turn OFF the power switch which is in the
path of inserting the pin).
2b) On the Bow Thruster shaft there are 2 closed cell foam rings outside
the hull which are compressed when the thruster is in full up and the
pin is inserted…my experience is if you do not insert the pin, you
will get a small amount of water in the forward bilge when sailing.
There is one closed cell foam ring inside the hull compressed when the
thruster motor is in the full down position.
2c) There is an oil seal just behind the propeller and this oil seal
probably needs replacing on your boat.
3a). The 2 foam rings outside the hull should be adhered to the foot of
the shaft and the gear box and ride up and down with the shaft.
3b) If the surface of the bow thruster well is oily it most likely is
because the seal behind the propeller needs replacing. A bad seal will
cause water to penetrate and water penetrating the thruster will cause
the oil to rise and possibly overflow when running.
3c) You should have fare access to this area to clean when the thruster
4) I am not sure about the 2 grooves in the sleeved penetration in the
5) There should be one closed cell foam ring inside the hull compressed
when the thruster motor is in the full down position.
6) There is an oil seal behind the propeller. It keeps sea water out
and also keeps oil inside the thruster. This oil seal is pressed into
the gear housing, and should be replaced when you service the unit. The
flat side of the seal faces the sea water and propeller. You may want
to use a little RTV (room temperature vulcanizing) silicone sealant to
help ensure that it stays in place and seals completely. I suggest that
when draining the thruster that you capture the oil in a transparent
container to see if there is any water in it. If there is, change the
seal behind the propeller.
7) My guess is that the water you had in your forward bilges was caused
by not pulling the wire and inserting the pin while under sail.
8) I assume that you filled the thruster to the same level that it had
when you removed it. If so, it was overfilled as it should definitely
not take that much oil.
Bill & Judy Rouse
s/v BeBe anchored at Bequia, The Genadines
--- In email@example.com, "Mike Ondra" <mondra@...> wrote:
[Non-text portions of this message have been removed]