Last night the bow thruster went off on its own

[DavidJ]

Thanks Vas and Croftie
The QL is very expensive and may not be available so found this to be interesting. Need to ask about the wiring following Croftie’s comment
8900C Joystick Panel For A Square Cut Out | Bow Thrusters Direct

 

[vas]

haven't seen let alone take apart a Vetus one. BTW the second one I have looks v.similar to the one you posted on #21.
the thing is that the delay circuit (QL also has one) is usually on the electronics on top of the actual thruster.
The dash logic (whatever it may be) could be bypassed as long as the three wires do their v.simple job pass some V down the one or the other line...
Like the on off on this side power I think cannot be easily integrated on your setup David. It doesn't look like a plain relay /switch thing most likely it's sending signals down to the b/t

still I'd start by taking the one you have apart

V.

 

[Boat2016]

QL bowthrusters have been the cause of quite a few fires. (you said Volvo so I am assuming it is QL). They do seem far worse than other makes for suddenly doing their own thing, the result of which has, on a few occasions, been a wrecked boat.

that’s because the switch design will activate thruster if the contact section departs from holder, the pin holds contacts off in middle and pushes in or out for Port/Starboard. Not a good design for the marine environment.

 

[DavidJ]

that’s because the switch design will activate thruster if the contact section departs from holder, the pin holds contacts off in middle and pushes in or out for Port/Starboard. Not a good design for the marine environment.

Agree
I was surprised when I took the ‘plug’ off the back off the unit and the thruster started.
Also apart from the forward battery switch which also runs the toilet, there is no other isolation ( on my version). I think myself lucky that I was on board (although asleep) when it self started, it could have easily ended in a burnt out motor or a lot worse.
Incidentally no self startups last night, so that’s 18 hrs with the brown wire disconnected so my bet goes on the joystick unit.
Thanks to all for support and advice. I’m still looking at marine alternatives to QL joystick.

 

[Croftie]

My guess is that the linked one 8900c joystick will still have electronics in it as it shows on/off buttons

The Vetus 4 wire:- The 2 inner wires at the plug are 12v +ve and 12v -ve. When "switched on" and the joystick is moved port/starboard 12v +ve is fed down one of the outer of the four wires depending of the direction the joystick is moved.

I am almost certain that on the 3 wire QL the brown wire is 12v -ve (earth not live) that wire as I said before connects to either of the other two depending on joystick movement.

A possible replacement could be
Vetus Joystick only for bow thrusters (excl connection cable (Vetus BPJSTA)
as that looks to be just a sprung loaded joystick.

 

[DavidJ]

My guess is that the linked one 8900c joystick will still have electronics in it as it shows on/off buttons

The Vetus 4 wire:- The 2 inner wires at the plug are 12v +ve and 12v -ve. When "switched on" and the joystick is moved port/starboard 12v +ve is fed down one of the outer of the four wires depending of the direction the joystick is moved.

I am almost certain that on the 3 wire QL the brown wire is 12v -ve (earth not live) that wire as I said before connects to either of the other two depending on joystick movement.

A possible replacement could be
Vetus Joystick only for bow thrusters (excl connection cable (Vetus BPJSTA)
as that looks to be just a sprung loaded joystick.

Thanks Croftie
Interesting that the brown wire could be -ve I’ll try and think up some test.

I do need something with a isolator although the ‘plug’ on the Vetus looks exactly the same as the single ‘plug’ on mine.
I’m just going to drive to my VP shop and test out stock and price of the upgraded QL joystick

 

[Croftie]

Yes easy to check the brown wire is -ve with a multimeter. You really need a dedicated isolator on the main +ve feed between battery and thruster.

You could of cause just make up your own panel with 2 push button switches.

 

[DavidJ]

Yes easy to check the brown wire is -ve with a multimeter. You really need a dedicated isolator on the main +ve feed between battery and thruster.

You could of cause just make up your own panel with 2 push button switches.

Thanks
Just checked at VP and no longer available
The investigation continues

 

[DavidJ]

still I'd start by taking the one you have apart

V.

Well, I took your advice and found a part number on the ‘plug’
CEMA P9B11VN
Available new on eBay from Italy so bought one.
I’ll still try to find a way of isolating for safety but I think that’s it and maybe helpful to others

 

[dunedin]

Hope you get the problem sorted. Sounds like well on the way to doing so.

However, I am intrigued as to the setup and usual practice on board. Perhaps different with us as on a sailboat, but we have two switches below decks for the bow thruster which are always off when not underway:
(A) A large battery isolator in the bow cabin, close to the bow truster battery; and
(B) A panel switch which sends power to the bowthuster control switch at the helm.
(The helm switch also has a power on/off routine, separate from the post/starboard thrust lever).

I would never leave the power on to the bowthruster overnight. Ditto the anchor winch, another high power device, for which there are a number of known instances where a switch fault has caused either fires or boat strandings (by winding in or out the anchor cable). 10 seconds to power on pre departure on our boat seems good reassurance?

 

[DavidJ]

I have isolation switches for everything else ie trim tabs, anchor, vhf, horns but not for the bowthruster and it was fitted from new!!
Although it is I’m not counting the front battery switch as a convenient isolator especially as it runs the toilet as well.
Of course I’m now looking for a neat marine switch which I can fit drilling just one hole.

 

[vas]

Well, I took your advice and found a part number on the ‘plug’
CEMA P9B11VN
Available new on eBay from Italy so bought one.
I’ll still try to find a way of isolating for safety but I think that’s it and maybe helpful to others

good find!

as Croftie said, if it's V-, definitely need to isolate V+, will check mine as well!

cheers

V.

 

[dunedin]

I have isolation switches for everything else ie trim tabs, anchor, vhf, horns but not for the bowthruster and it was fitted from new!!
Although it is I’m not counting the front battery switch as a convenient isolator especially as it runs the toilet as well.
Of course I’m now looking for a neat marine switch which I can fit drilling just one hole.

Interesting thanks. Yes it does sound like a specific isolator switch for the bow thruster would be useful - and help you sleep more soundly!

 

[solitaire11]

My ql does this.. only when the control gets wet.

 

[oceanfroggie]

On my boat for the first time in a few months and at about 2pm my bowthruster decided to go off. I switched off the power battery then switched on again and after a minute or so it went off again. I can make the thruster go right and left by using the toggle then it takes over on it’s own. The thruster is an original Volvo one.
its now 2:12pm and I’m going back to bed with the power off.
What could it be??

Check for rain Water ingress into the microswitch. The rubber boots on the joystick are notorious for leaking when they perish.

Similar happened to us when we were descending through a 102ft hydro dam lock raining heavy. When I turned the engine ignition back on to exit the lock bow thruster locked on right (stbd), had to hold it to port to keep it off until berthing in Limerick marina. Pulled the panels off under the cockpit dashboard and discovered rain water ingress into the Joystick microswitch assembly. Dismantled and WD40 helped dry it out. Hooked it up and it's never given trouble since. Had to replace the rubber boot on the joystick.