Bow thruster stopped working

[DaveR]

OK, I am one of those boaters with a "girlie button" but after using one for over 40 years at sea I appreciate how useful they are. Legacy came with one fitted and she is from 2004. It is a BCN 55kgf unit (now taken over by Twin Disc as a BT 55)

 

Yesterday whilst winding at Tarleton it worked, then stopped working part way through the manoeuvre. I thought I had picked up weed and so today I have been down the weed hatch. My findings are :-

 

Propeller is clear, turns easily in both directions.

The solenoid is clicking away when the control down aft is pressed.

Voltage at the motor is 12.8 with the engine running.

 

Is there anything else I can check to track down what has gone wrong? The manual only suggests that the solenoid has given up.

 

Thank you

Dave R

 

[Alan de Enfield]

3 minutes ago, DaveR said:

OK, I am one of those boaters with a "girlie button" but after using one for over 40 years at sea I appreciate how useful they are. Legacy came with one fitted and she is from 2004. It is a BCN 55kgf unit (now taken over by Twin Disc as a BT 55)

 

Yesterday whilst winding at Tarleton it worked, then stopped working part way through the manoeuvre. I thought I had picked up weed and so today I have been down the weed hatch. My findings are :-

 

Propeller is clear, turns easily in both directions.

The solenoid is clicking away when the control down aft is pressed.

Voltage at the motor is 12.8 with the engine running.

 

Is there anything else I can check to track down what has gone wrong? The manual only suggests that the solenoid has given up.

 

Thank you

Dave R

 

 

It may not be the cause, but I'd suggest that getting 12.8v with the engine running would indicate a flat battery / battery problems / alternator problems.

 

A solenoid 'clicking' would often indicate insufficient voltage, or a bad connection (either the negative or the positive) in the system (not necessarily at the BT motor)

 

What voltage and current are you getting at the alternator ?

Edited August 18, 2019 by Alan de Enfield

[MHS]

Check the voltage both sides of the BT main fuse. If you have 14.2v on the battery side and 12.8v on the BT side, replace the fuse. They can partially blow or burn out. 

[Kudzucraft]

Did you check the voltage leaving the solenoid going to the thruster motor? Could be the contacts inside the solenoid are burned and while it is operating, it is not allowing power through it to the thruster motor.

[WotEver]

2 hours ago, DaveR said:

Voltage at the motor is 12.8 with the engine running.

Is this actually ‘at the motor’ or somewhere else in the circuit?  If it’s actually at the motor then you could well be needing new brushes. 

[Momac]

A burned solenoid was the case with my friends boat.

 

Solenoid possibly could be  burned due to failing battery causing low voltage and high current.

 

Initially try a known good starter battery.

[DaveR]

Thank you one and all, some more things to try and test.

[Tractor]

Lift the brushes a few times under spring pressure, then push down. Brushes often stick due to damp and lack of use.

 

[Alan de Enfield]

2 minutes ago, Tractor said:

Brushes often stick due to damp and lack of use.

The OP states the BT stopped working whilst using it.

That would tend to suggest a 'failure' rather than being 'stuck from lack of use'.

[Tractor]

Operation becomes intermittent, then stops, with the brushes failing to make contact. Checking the brushes in this way is the quickest ‘snag’ to eliminate. If this makes the motor run, I would then recommend lifting the motor out for a service to clean the commutator and re bed the brushes, checking the brush boxes for corrosion and brush dust.