Re: [Amel Yacht Owners] Re: Bow thruster Linear Actuator


Hi Andrew,
I'm interested in your pulley system to raise/lower the bow thruster.  Did you take any pics?
SM243 Kristy
Still on the hard in Fernandina Beach waiting for the Cdrive to return from France...I guess the whole country takes vacation the whole month of August.

From: "Dr Andrew Lamb andrew.lamb@... [amelyachtowners]"
To: "amelyachtowners@..."
Sent: Sunday, August 24, 2014 5:45 AM
Subject: RE: [Amel Yacht Owners] Re: Bow thruster Linear Actuator

An update on my Bow thruster Linear Actuator problem.
I think a fuse in the line to the motor sounds the best plan – easy to change – the 10amp fuse on my unit is inside the box on the circuit board, requiring the removal of 4 small screws to change.
Initially I got a replacement motor from Amel for 324 euros without taxes or delivery however this turned out to be the wrong motor and did not fit the drive (either physically to the drive, but also the worm thread sizes were different) the numbering on it seemed to suggest that it was for  linear actuator with a 50cm  travel, whereas the actuator that I have has a 20cm travel (maybe the later Amels have a longer travel for the bow thruster?). The only alternative from Amel was to buy a complete drive and motor replacement which was going to be 1217 euros without tax or delivery, but basically they were going to send me the drive unit to add to the engine so I did not have confidence that this was going to be the correct drive, so I sent the motor back to Amel.
I contacted SNT who manufacture the units and they have supplied a replacement motor for 300 euros including tax and delivery – I now have this and this is the correct motor fitting both the worm drive thread and the drive unit. I also sent the broken unit to be rewound and reconditioned to (a London based motor repair company) who have rewound the motor and reconditioned the motor - changed the brushes etc, this cost 185 GBP including taxes and delivery – this I will receive in the next day or two, so I should have a replacement backup also. I also got two new hall effect sensors from Amel at 24 euros each.
So over the next few days I am going to put the actuator back together then study the circuit in more detail and probably either add a thermal circuit breaker set at 5 amps (the SNT documentation seems to suggest that at maximum load it will draw 4 to 4.5 amps) or a inline fuse as in the previous message which could be easily changed.
I also took Bills advice and bought a battery tester – this was quite interesting – initially 5 batteries failed. With 2 of them (scored 300amps instead of 1000) I found that the nuts fixing the wires between the batteries were a bit loose – so I tightened them and left the batteries to charge overnight and the next day the both passed. Another 2 (scored 650 amps) when I took them out jiggled them about a bit and then made sure that I had a really good contact between the tester and the terminals they also passed. The only other battery that failed was the starter battery (again marginally 700 amps)  I re-tested this after motoring for a couple of hours and this also passed.
Incidentally we have just completed 3 weeks holiday in the Balearics – we used a pulley system to lift and lower the bow thruster – worked a treat!
SM2k 472
Canet en Roussillion, France

Sent: Friday, July 11, 2014 7:25 PM
Subject: Re: [Amel Yacht Owners] Re: Bow thruster Linear Actuator
Hello Andrew,
Several years ago I made silly mistake which resulted in that motor being totally burnt out.This was a potential disaster as Amel told me that the motor was out of production but Maud managed to find one and sent it to me. When I fitted it I installed a 10 amp fuse in it’s circuit in the connection box and tied some spares onto the box for the next time there might be a problem.
I sent a message to this site advising every one to do the same and so it appears that Amel may have done the same at some stage or that a previous owner of your boat did it.
Fitting the fuse in the wire driving the motor was very simple and i strongly advise all owners to check to see if a fuse has been fitted in their  boat and if not fit one as a matter of urgency. All that is needed is an inline fuse holder and a few 10 amp fuses.
                                     Good luck,   Anne and John,  Bali Hai,  SM319,  for sale in Malta.
Possibly someone with a Super Maramu near #472 could take some photos of the location of the micro switches and post them. I would, but with 387, I fear there were some changes in the almost 3 years of production.
BeBe 387
On Fri, Jul 11, 2014 at 3:43 PM, derickgates@... [amelyachtowners] <amelyachtowners@...> wrote:
I can tell you from very recent experience that Brava (SM2K #400) has a 10 amp car fuse installed in the linear actuator, and it works.  I had neglected to put up the bow thruster until I was out of the harbor in some swells, and when I tried to bring it up in those conditions there was enough pressure on the bow thruster shaft that the bow thruster's pointed end on the top of the motor jammed against the edge of the receiving cone, thus failing to fully rise and thus not giving me the familiar alarm saying "I am fully up!".   Inspection showed that the bow thruster was jammed, and it would not go up or down.  I shut off the system in short order and slowly returned into the harbor. 
Back at a mooring I was able to physically unjam the motor/shaft by looping a line around the shaft near the top (pointed end) and pulling really hard.  The up/down controlls still did not work.  I then examined the "black box" (linear actuator) by taking off the 4 cover screws and found that the 10 amp car fuse had blown.  Natually I did not have any spares aboard, so a crew member shorted the fuse with a small piece of wire and voila the bow thruster once again went up and down!
So under certain circumstances like my jam, the 10 amp fuse does serve a function to avoid burning out the motor that raises and lowers the bow thruster.  It is not clear to me why your 10 amp fuse failed to protect your motor.  Am I correct that you tested the fuse for electrical continuity and not just by visual inspection?   Please do keep the rest of us informed of your progress in understanding the system.
SM2K #400 Brava
On the hard in Antigua

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