Problem with rear thruster on R-27

[JohnH]

As we were docking today, the rear thruster on our R-27 suddenly stopped working. It was engaged and working when it quit. I had not reversed its direction or done anything I know to be wrong. The battery voltage looks OK, and the front thruster works normally. When I try to engage the rear thruster, I hear rapid "clicks" and the light on the controller blinks rapidly. (When using the front thruster, the light is on steadily.)

Any suggestions, please? Without trying to prejudice the discussion, the "clicking" sounds like a solenoid engaging and then disengaging. Is this plausible? If so, what do I do? I have reviewed previous postings on replacing the shear pin, and they are frightening. But the behavior above does not sound like what I would have expected from a broken shear pin(?). Is it possible that something has jammed the thruster propeller, and there is some kind of overload circuit that trips the solenoid?

Grateful for any help,
John H

 

[walldog]

As we were docking today, the rear thruster on our R-27 suddenly stopped working. It was engaged and working when it quit. I had not reversed its direction or done anything I know to be wrong. The battery voltage looks OK, and the front thruster works normally. When I try to engage the rear thruster, I hear rapid "clicks" and the light on the controller blinks rapidly. (When using the front thruster, the light is on steadily.)

Any suggestions, please? Without trying to prejudice the discussion, the "clicking" sounds like a solenoid engaging and then disengaging. Is this plausible? If so, what do I do? I have reviewed previous postings on replacing the shear pin, and they are frightening. But the behavior above does not sound like what I would have expected from a broken shear pin(?). Is it possible that something has jammed the thruster propeller, and there is some kind of overload circuit that trips the solenoid?

Grateful for any help,
John H

Check the fuse to the rear Thruster. I believe it is a 100 amp in the port step compartment in the cockpit. That fuse type can be intermittant.

 

[knotflying]

I have no thruster experience, but if there are separate fuses for front and rear try switching them around and see what happens. Also make sure all your connections are clean the symptom sounds a lot like when a starter clicks because of a bad connection or bad battery. Since the front thruster works you know the battery is good.
Your other option is call the thruster manufacturer for advice.

 

[bsilveria]

I have had the same problem you are having. both times it was the fuse........ Made a clicking sound, then quit :cry:

 

[trailertrawlerkismet]

Also check the thermal circuit breaker to see if has tripped and needs to be reset, mine is in the genset locker....probably not, because you are hearing noise. Next if you've had your boat in the water any length of time and have not inspected the thruste chamber you may have it overgrown with barnacles, which would cause it to not work properly.Let us know what you find out.

Jim

 

[SUWANNEE]

Last Christmas while in the Keys, we had an issue with GRASS that cause "one" of the BIG fuses for the thrusters to burn out.

The bow thruster worked fine but the stern clicked a little then totally died and then the bow lost power but still ran.
The thrusters apparently need both fuses to keep working. When you look at the wiring diagrams they look separate.

Hopefully not the accursed shear pin

 

[sportner]

Definetly a fuse, the same thing happened to us while out last time.

 

[JohnH]

Many thanks to all of you for your counsel. It was indeed the fuse. Not sure that I understand why a blown fuse would still allow any activity, such as the "clicking", but replacing the fuse restored the thruster. The construction of the original fuse seemed odd in that the external tabs could impose mechical stress directly on the internal fuse section. I wonder if the failure was actually mechanical instead of an electrical overload. If the fuse "broke" instead of "blew", it might allow some kind of intermittent or high-resistance contact that could explain the odd behavior. Just speculating.

I really value this forum. Thanks again.

-- John H

 

[GulfSailor]

The big fuse protects the heavy duty circuit that carries the power for the thruster motor.
When you operate the thruster the joystick sends power to the solenoid (an electrically operated switch that uses a small current to switch a big current) that switches the power to the thruster.
If that big fuse has blown then no power can get to the thruster, but the solenoid should still operate, which is probably the clicking sound you hear.

 

[ronker100]

First things first, replace the thruster fuse with a breaker...save you money in the long run and you wont be stuck trying to find one when needed....
Cheers, Ron