Bow Thruster won't come up

Duane Siegfri

We left the dock today with this series of events:

1.  Deployed bow thruster.  Tested to port and stb.  All OK.

2.  Left dock using thruster and went to fuel dock.  Along the way I toggled the thruster to go up (back into the boat).  As soon as I toggled the switch, the alarm came on that normally announces the thruster is all the way up or down.

3.  When I got to the fuel dock and tied up, I toggled the thruster to go up and it responded normally, with the alarm sounding only after it had fully risen.  Upon leaving the dock we deployed the thruster and it responded normally.  I toggled the thruster for UP and the alarm sounded instantly without moving the thruster up.

4.  I checked the fuse in the small black box in the thruster compartment and it is fine.  I tried a new one anyway and the alarm sounds as soon as it is toggled up.

5.  The thruster prop motor runs fine.

6.  I tried separating the magnetic (?) sensors that define full up or down movement (of course the "down" sensor was in contact with the static sensor), and that didn't change anything, the alarm still sounds as soon as you toggle the thruster for UP.

7.  I checked voltage across the fuse in the black box inside the thruster compartment and there are 0 volts with it on, or toggled for up or down.

8.  I checked for loose wires and didn't find anything.

Question:  what would cause the alarm for full up or down to sound when the thruster is fully down and you toggle it up?

Question:  what's the best way to raise the thruster without help from the up/down motor?

Question:   what else could I check to determine the cause?



Wanderer, SM#477


I recently had the problem of the down sensor not working, although I did not experience the same symptoms as you have described. Replacing the sensor solved the problem.

As regards raising the thruster without power I am told by Amel to connect a halyard to it and haul it up, although I have not tries that.

Ya Fohi, Amel 54 #98


Hi Duane,

I have had a similar problem on my 54. I have not yet got to the bottom of it but I believe it is the  top and bottom sensors that are not actually sensors. They are simply push button switches. When the frame is lowered it clamps down on the bottom switch. There are two cables on a toggle, and ditto at the top. This then sounds the alarm and stops the motor running.

I found that if I pressed them a few times by hand then it worked fine. So I suspect there is a poor/ intermittent connection within the button/toggle.

I reiterate I am not 100% sure about this. It is what I think

If you try this and it works then all you need is to order a new pair and a spare pair because I think this is a common fault.

I would love to know, as I have left my boat out of the water in Antigua whilst I am in the UK, and would order the parts if that is indeed the problem.


Amelia (54 #019)

Duane Siegfri


I have the 53' Super Maramu.  The limit switches on my boat don't have buttons. They must be sensors that work on a magnetic basis.


Duane Siegfri


Where did you buy the sensor?


Duane Siegfri

Is the motor and drive that raises and lowers the thruster and thruster motor a jack screw arrangement?



Yes, it is.

Bill Kinney
SM160, Harmonie 
Great Abaco Is, Bahamas

Duane Siegfri

A fellow Amel owner here in GA loaned me one of his spare sensor and bingo!  The sensor was the problem and now I'm looking for replacements.  Maud on Friday said she would let me know on Monday if they have any in stock.

These sensors are unusual because they are "normally closed" (NC) reed switches, based on the diagram on the sensor.  I've looked a lot of places and have not found an NC reed switch with a 20W and 0.3A rating.  If it's an NC switch then it's a 10W switch, or a 0.1A rating.  Frustrating.  Also, most don't have an LED light.

Any thoughts on a company to check with?