Re: [Amel Yacht Owners] Bow-Truster overheat

Porter McRoberts

Simply incredible, these responses. 
They are so very appreciated. I learn so much from this forum, it’s about worth the price of admission!
Thank you all. So much

Porter and Helen
S/V Ibis
Amel 54-152

On Jun 29, 2018, at 12:20 PM, Beaute Olivier atlanticyachtsurvey@... [amelyachtowners] <amelyachtowners@...> wrote:


Hello all AMEL 54 owners,

there is indeed a thermic switch on the bow-thruster motor. It is connected to one of the carbon brushes. If you have already had it stop the motor, several times, or you purchased a used boat and you don't know about the over-use of the bow-thruster by the former owner, it may be time to check the carbon brushes of this motor.
Indeed, worn out brushes lead to warming up where the brushes make contact with the rotor. And worn out brushes make the motor less powerful, then you may use it a longer time for the same amount of thrust.
If you see a lot of carbon dust around your BT motor, it's time to check/replace them.

Moreover, when AMEL says that you should turn ON the generator when using the bow-thruster (and the 100A battery charger), this is because the bow-thruster will work with higher voltage (the voltage drop will be less if the charger is ON, and as the main engine alternator is not charging much at low revs). With higher voltage, the amperage will be less, the warming up of the thermic switch too and the wear of the carbon brushes too.

Now, I agree that you don't absolutely need to turn on the generator and battery charger in any conditions. But do it if you enter a harbor that you don't know (you may use the BT a lot) or if the wind is strong.

In the french Navy, when a vessel enters a harbor, every means of power is systematically turned ON, in case one fails. Bill R will tell us how they do in the US Navy, but it may be the same.
This was the idea of Captain AMEL and Mr. Carteau when they decided to give the "Generator ON when docking" advice.

Rüdi, don't worry about too much wear on your generator, it is a very resistant piece of hardware...

Keep enjoying easy dockings!!


On Friday, June 29, 2018, 5:42:37 PM GMT+2, 'Mohammad Shirloo' mshirloo@... [amelyachtowners] <amelyachtowners@...> wrote:


The main reason to run the Genset while using the bow thruster is not to reduce the load on the batteries. Putting out 400-500A for short bursts will not have a significant negative effect on the batteries.
By running the Genset you are maintaining a higher voltage to the bow thruster, reducing the current requirement and thus reducing the heat generated in the bow thruster and all associated wiring supplying the bow thruster. This will maximize the time the bow thruster will function before the thermal cutoff kicks in.  Therefore for us it is not a calculation of battery vs. generator life, but an issue of safety. A few extra seconds of bow thruster availability may make a big difference in the result of the maneuver.
Mohammad Shirloo
323-633-2222 Cell
310-644-0908 Fax

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Friday, June 29, 2018 8:32 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Bow-Truster overheat


Thanks for all your thoughtful responses. This is a great forum and I have learned a lot within a short time about AMEL. I love it!

Here some comments on your responses: 

I’m not using the bow truster more than 5-6 seconds per burst. When I use it, I’m carefully not to overdue and I usualy waiting to cool down a bit between 2 burst. Thats why I was wondering how fast it was paused by the system….

No, I don’t use generator while use the bow truster, as AMEL and many others recommending. I agree with Thomas about it. 
- In one hand the Engine is running always when use the BT and is supporting the batteries as well . 
- On the other hand I do not extensively use the BT so my Batteries should be able to carry the load. 

- AND most important; I don’t want to shorten the live of my GenSet just to help the batteries a bit.
In my opinion is; The live of a Diesel engine is shorten by too many short usage without much load and without running it at leased 30min at a time. When I turn the GenSet on, I use it for many things at the time, Laundry, Water-maker, heater, charging, whatsoever. Therefore it runs at leased an hour when it’s on.

We don’t had the 425A fuse on #55 either. Olivier recommended to install it and also an emergency shutoff in the BT compartment . So we did. ;-)

Fair winds!

Von: <amelyachtowners@...> on behalf of "'S/V Garulfo' svgarulfo@... [amelyachtowners]" <amelyachtowners@...>
Antworten an: <amelyachtowners@...>
Datum: Donnerstag, 28. Juni 2018 um 13:33
An: <amelyachtowners@...>
Betreff: Re: [Amel Yacht Owners] Bow-Truster overheat


Hi Mohammad and Aty,

So you don't have that 425A fuse on Kokomo?
It'd be interesting to have other data points. 

When we started seeing A54s for sale, someone from the yard in Hyères told us Amel started to fit the emergency disconnect on 54s  after instances of incidents where the bow thruster wouldn't stop. The thermal switch should provide that safety stop, but maybe they felt there should be a manual override too, in case.

By the way, it was in the same sentence as "have the genset running when you use the bow thruster" that raised a few eyebrows in this group a while back. At the time, not knowing better, I took it for granted. Sufficient and safe, yes. Necessary?, I'm not sure. We don't do it anymore as we don't go to marinas that much and when we do, we try to play the game of least-bow-thruster-usage to improve our handling skills, and our batteries can handle the high current discharge.

Fair winds!


On Thu, 28 Jun 2018 at 05:38, 'Mohammad Shirloo' mshirloo@... [amelyachtowners] <amelyachtowners@...> wrote:

Hi Thomas;
Your fuse may have been added on because I've heard some surveyors and insurance companies regard this situation as unsafe and will require the fuse to be added. I'm pretty sure that we were told by Olivier during our survey that the bow thruster is directly connected to the batteries. When I inquired about the reason, I believe the response was that Amel felt that the safety of the boat, when absolutely needing the bow thruster to be operational, was more important than the possibility of the bow thruster being damaged due to overuse.
The emergency disconnect is a manually operated switch which would require intervention form a person to stop current flowing to the bow thruster.
Mohammad and Aty
B&B Kokomo
Amel 54 #099

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Wednesday, June 27, 2018 2:01 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Bow-Truster overheat


Hi Mohammad,

On Garulfo (54-122) there is also a 425A fuse on the positive cable and an emergency disconnect (big red button), both housed in the box inside the forward locker. 

I recently found the emergency disconnect to be rusted frozen so it's on the list for replacement. 

I would encourage others to test the emergency disconnect as it has a carbon steel backing plate and is mounted without any kind of waterproofing so is bound to rust. 

Fair winds,


On Wed, 27 Jun 2018 at 19:27, 'Mohammad Shirloo' mshirloo@... [amelyachtowners] <amelyachtowners@...> wrote:

Hello Reudi;
Yes, the Amel 54 has a thermal cutoff to prevent damage to the thruster as well as continuous high current draw (Around 550 Amps at 24V) which could lead to fire on board. We've had the thermal cutoff kick in  only a couple of times and it has reset in a matter of minutes. We have not timed the exact reset duration.
I'm not aware of any adjustments in the thermal cutoff. The bow thruster has a direct connection to the batteries without a breaker. The thermal cutoff is the only safety items preventing major damage to the thruster and/or wiring.
Try to use the thruster in bursts (less than 15 seconds), as much as possible, so it has time to cool down between usage. We try to over correct a bit when we use use the BT so as the bow falls off, the BT has more time to cool.
Mohammad Shirloo
323-633-2222 Cell
310-644-0908 Fax

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Wednesday, June 27, 2018 9:58 AM
To: amelyachtowners@...

Subject: [Amel Yacht Owners] Bow-Truster overheat


Dear Forum

On my Amel-54 I discovered that the bow truster stops working after repeatingly use within 10-15 min timeframe.

I used the bow truster a bit more than usual when I practiced some manouvers first time; - and on a second occation when I had to manouver in a marina with a lot of windguests of 18+ kn and another chain over my Anker...

It stopped working and after a while (maybe 10 min.) it re-started & operated normaly. I know BT Is not made for constant use, - only few seconds at a time. Then wait and re-use another time.

Question from a beginner:

Does the bow truster has a termic fuse which is activated after some time of usage to save the motor from overheating? 

Does anyone know exactly how it works and if this can be adjusted because I think the BT on Wasabi switches of quite fast. Any ideas or other information?

Best regards


SY Wasabi A54#55

Sailing Cyclades GR.

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