Haunted Lewmar 185 thruster

Last evening I received a call from my marina telling me my bow thruster has turned on and had been running for an extended time. I obviously had not turned off the main disconnect for the thruster, but I typically have always left it on with no prior issue. Any suggestions?

Shor(t)e circuit??
Always turn off.
They drain batteries real fast!!
Surprised they bothered to call
Our old marina would not have even noticed!!!

Talk to a Lewmar rep, something is clearly faulty. Perhaps there was an installation problem?

My Lewmar 'self isolates' after a period of time. To use the thruster you have to press and hold a button on the thruster control for a few seconds. Red and green lights come on and it is then ready for use. If the thruster has not operated for some time (10 minutes?) then it isolates and the controls are inactive.

seab,
I had same issue a couple of weeks ago, same model. Mine are 7 seasons old.

#1: get someone to turn off the main disconnect for the thruster. Then maybe charge your batteries, depending on the situation.

In my experience the problem was with the potted electronics in the joystick assembly.

I have experienced two failure modes over the last season. First was when my gal's 500W ham radio power amp signal coupled with the wiring on the boat. When she hit the morse key, boat spun around the mooring buoy! Was kinda funny at the time. Turnoff main switch for the thrusters, problem solved. No problems with thrusters for a year.

Then this spring I had random runs of the bow thruster to starboard. That got worse over the course of a week. My diagnosis lead me to the potted stuff on the bottom of the stick assembly. That stick assembly had a rough winter in La Conner, which may have contributed to its failure.

The electronics control the LED's on the face panel, and are also in series with the primary contactors on the joystick. That means when the lights are out, no go. Lights on, thrusters will run if there is adequate voltage/power available. They will kick off if your battery bank is low.

In the manual, I saw that it's OK to add an auxiliary switch set, like you might do for lower helm. Says use a 5 amp rated switch, which covers the inductive kick from the coils of the power relays on the motor.

Knowing that "other" switches are OK, I rewired the joystick to be a dumb switch set, mainly to prove I was right about the failed electronics, and secondly to save over half a boat buck. Works great, very reliable, just no pretty green and red lights. Requires new procedure to only have main switch on when thrusters are needed, not an issue for me. And so my springline skills will once again deteriorate at the swing of the Lewmar joysticks!

I'm sure others have had this maddening experience which is the other reason to share this workaround here.

Another possibility would be the "black box" on the side of the motor. That's what its called. Mine checked out OK, didn't seem to be part of the problem.

You may want to look at the brushes on the motor too, if they ran for extended time.

Hope this helps. Try it if you are a plug and player, otherwise, swap out the joystick. And the 500W amp is banned from my boat!

It appears a smiley window on the bridge has been left somewhat unzipped at the bottom and had allowed rain to come in and across the console. Possibly that water situation migrated into the switch assembly and possibly was the cause of my random unattended starting. I'll zip the window and swap the switch and keep everyone posted.

Thruster will need a run signal to run - I a thruster run when the control loom was wet with salt water and that is all it took for a circuit to be made. Some makers only use a simple plug arrangement so I would check that out also.
DT

re that last post from me - sorry for the typo - that should have been "I have seen a thruster run..."
Further to what GoneFarrell above has said - he is correct. In most thrusters all your dealing with is a series wound DC motor directionally switched via a solenoid. Applying either a positive or negative (direct from the main power lug) to the directional coils is all thats required to make it work. SP thruster its a negative, CM is a positive and so on. The electronic box is there for a delay relay function port / stab and other specialty functions that I wont bore you with.
so when you add to that a loom to connect to your joystick the possibility of a short in the loom making the thruster work randomly is for sure a possibility.
Bridge the red to either white or blue on a SP loom and it will run
DT

Great suggest on testing! I will do the jumper wire thing this weekend and determine if the circuits itself is good, leaving me with either a bad switch or poor connections.
I also plan to cut a Starboard doughnut to chalk and place under the thruster control switch which will elevate the push-button panel off of the dash and protect it from future water intrusion.
Thanks for the advice. This forum is super.

seab,
The Starboard lift is a good idea, I might try that too, thanks!

Another water detail: if the black plastic ring that clamps the stick assembly down is a one-piece ring, consider cutting it at 4:30 and 7:30 to allow any water on the button panel to drain off. This drains the button panel of any water on my boat.

The button panel seal is on the bottom of the main assembly, so it will still clamp tight to the mounting face. I'd post a pic but not near the boat for a while.

We had a thruster fail on our canal trip, which made locking more interesting. Anyway, the repair guy tossed the electronic, gotta-turn-it-on-red-and-green-light-panel and stuck in a toggle switch with no lights. It worked from then on. With a shutoff there is no need for the electronics unless you like seeing lights.

yep - all your doing is switching directions.
the issue could be if your thruster manufacturer uses their joystick to contain the relay(that makes a delay port to starboard) this protects the contactors from the directional change. CM is like this SP are not - theirs is the black box under the solenoid. Either way the control side only requires a small amount of current to run .6a or so @ 12v.
In the early days of thrusters all there was were the "gate" style joysticks connected directly to the solenoid, most still working today. Add fancy electronics and it all turns to custard.

Thruster switch donut

Well, here is my solution to water getting into the switch and harness and causing a short circuit to my thruster.
I cut a Starboard spacer with a hole saw, then used a smaller hole saw to cut out the center. This assemble was then bedded to the console and a new switch installed.
So far it seems to work well and is easier to reach. Next I think I will go the the hardware store and buy a PVC pipe cap to fit over this assembly, and when the boat is not in use the switch will be completely covered and protected.

Another good use for starboard. I use it everywhere.

Thrusters running on their own has happened several times before in this forum. It is prudent to have a disconnect switch on the thruster power. Think about your diver and where he puts his hands.

My 140TT did the same thing in early January - the boat has been in the water about 18 months. Yes... I inadvertently left the main switch on. The joystick is dry in the wheel house, the contrlol cable is dry the entire distance and the thruster is dry as well - no water. The thruster started on its own in the middle of the night and ran for over half an hour before a live aboard neighbor woke up from the racket, climbed on board and shut it off. It's mounted as a stern thruster and all the plastic has melted down. It's toast. We weren't far from catching the fiberglass in the lazerette on fire and having a real issue. All you have to do is google and learn that this has happened quite a few times in the last few years - Lewmar now has what they call Gen 2 compliant joystick, control cable and a blue box converter. BTW... no one from Lewmar ever contacted me about it and I'm registered w them re warranty, etc.

the only way that a DC thruster will work on its own is it receives a control input signal - usually this is due to the control loom running thru water.

Delta Tango said:

the only way that a DC thruster will work on its own is it receives a control input signal - usually this is due to the control loom running thru water.

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My remote control went crazy and had a solid signal asking for thrust constantly. The distributor told me that it couldn’t happen. I sent the remote control and the remote panel back and they found that it was bad and calling for thrust all the time. I reinstalled it and it works fine now. But I also now turn off the main battery switch for the thruster when we are not on the boat so it can’t go on by itself when no one is there.

Comodave said:

My remote control went crazy and had a solid signal asking for thrust constantly. The distributor told me that it couldn’t happen. I sent the remote control and the remote panel back and they found that it was bad and calling for thrust all the time. I reinstalled it and it works fine now. But I also now turn off the main battery switch for the thruster when we are not on the boat so it can’t go on by itself when no one is there.

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Hi, Just rereading this thread as I try to avoid Coronavirus in
March of 2020. I once had a Cutwater 30cb. It was a late model 2017. I think the Lewmar thrusters were new to Cutwater because of supply problems. Anyway we spent the entire 2018 cruising season being plagued (or as I came to describing it “possessed) by the bow thruster going off randomly, both with the boat underway and when docked. The worst instance happened when we were going thru the gorge entrance to gorge harbor in Desolation Sound. Almost ended up on the rocks. The dealer’s best mechanic worked on it a half a dozen times assuming most of the causes and solutions mentioned earlier in this thread. Nothing worked. He finally got Lewmar to acknowledge that there was a problem with the design of the controller. They promised to send replacements. It took over a month for anything to show up, an then they sent the old model. More waiting! When correct ones finally arrived they had a “little black box” attached. That finally solved the problem. I can also report that there’s no proof to support the the theory spread by some that the “little black box” contained a miniature mouse running on a treadmill. I for one believe “no animals were hurt producing the solution.” I also sold the boat as soon as possible.