Smoke from bow thruster

[philipm]

Newbie question. Was out on the boat yesterday. Usual bit of manoeuvring in the marina and then set off downstream. A few minutes later I noticed what appeared to be a small amount of smoke which seemed to be coming out of the cabin. I stopped the boat to investigate and almost as soon as I stopped the smoke disappeared.

I was left thinking "did that just happen?".

Anyway a little while later I turned to go back upstream and found the bow thruster would not work. It would beep but no power. I left it off for a few minutes and it worked again......I'm thinking the smoke and the bow thruster issue must be connected but what happened?? And why did it start working again?

 

[jrudge]

They have a thermal cutout.

They do get hot and are very high current which is why you can’t use them for long.

I would inspect it and the solenoid before using it again. You really don’t want a fire.

I used to ( May now put on in today ) have a smoke detector in the thruster space for this reason.

 

[philipm]

Thanks, that must be what it was.

I did use it more than usual yesterday because I was on my own - but not a huge amount - so it's disconcerting that was enough to cause a problem.

 

[Seastoke]

Thanks, that must be what it was.

I did use it more than usual yesterday because I was on my own - but not a huge amount - so it's disconcerting that was enough to cause a problem.

Don’t you have to reset the thermal fuse

 

[philipm]

All I did was turn off the bowthruster completely for a few minutes and then turned it on.

 

[Seastoke]

All I did was turn off the bowthruster completely for a few minutes and then turned it on.

Tie up well on your berth , do you have a remote for it if not communicate by phone and get some one to operate ,where you look at motor and touch ,it could be hot smoke is heat ,ideally a clip on amp meter

 

[philipm]

Tie up well on your berth , do you have a remote for it if not communicate by phone and get some one to operate ,where you look at motor and touch ,it could be hot smoke is heat ,ideally a clip on amp meter

Thanks. What do you mean by "it could be hot smoke is heat"?

Thinking back, the "smoke" didn't seem to have a smell.

I do have an amp meter but wouldn't know what to look for with it...

 

[TQ1]

You probably already checked this but I had a similar problem and upon investigation the earth lead was loose on the bow thruster. This caused some smoke and a hot smell!! Whether it was ever installed correctly or just came loose I don't know.

 

[AdeOlly]

Smoke could be from dirt on the motor casing or any of the connections if not clean and tight, or from the bearings of the motor itself. Personally I'd go through all the connections thoroughly to clean and tighten. Once all looks good I would tie bow up well and have somebody else run the thruster whist you watch, with ammeter hooked up and a infrared thermometer to see what gets hot. Fire on-board is the absolute worst scenario in my book.

 

[philipm]

Thanks.

I am going to have a close to look at it. What should I connect the ampmeter to and what should it tell me?

 

[AdeOlly]

Thanks.

I am going to have a close to look at it. What should I connect the ampmeter to and what should it tell me?

Ideally, if you have, or can borrow one, I suggest you use a clamp on ammeter on the cable from battery to thruster motor. What you are looking for is that the motor is drawing the correct current. This will be in the tech specs for the unit, and probably on the motor itself. If it's drawing too much or too little suggest the need to investigate further. Too much would worry me more as the circuitry / motor could become overloaded and hot.... However, there may well be a breaker in the circuit anyway to prevent this, so perhaps check for that first.

 

[rosssavage]

Philipm - what sort of ammeter do you have?

Stall current of a thruster motor will be in the hundreds of amps, and running load will be potentially 100amps or more depending on the size of your motor.

You need a clamp on type ammeter for this job....

 

[Croftie]

A Vetus 12v 55Kgf bow thruster shows around 350 amps using a clamp meter if that can give you a guide.

 

[philipm]

Thanks all. Think I have the manual for the bowthruster so will have a look.

My ampmeter is from Draper I recall but can't recall spec. It doesn't have clamps though so it may be no use by the sound of the above posts.

 

[rwoofer]

I've witnessed a bit of smoke from a bowthruster turn into a full fire within 10 mins, sinking the boat. People lucky not to have lost lives. Don't use it till you get to the bottom of the problem!

 

[Croftie]

Hi

A clamp meter looks like this
https://www.ebay.co.uk/itm/VICI-CM-...120407?hash=item23ba0ab997:g:6PsAAOSwNRJckJ-C
Check that it does DC Amps (as above one) many of the cheaper clamp meters only measure AC amps

 

[Freebee]

I've witnessed a bit of smoke from a bowthruster turn into a full fire within 10 mins, sinking the boat. People lucky not to have lost lives. Don't use it till you get to the bottom of the problem!

+1 I was very lucky I had fried wiring in the area of the thruster much smoke due to running too much........ but luckily I saw it and disconnected the battery to investigate. but I was seconds away from a full on boat fire..some low spec bow thrusters should operate for short bursts only

 

[Lower Limit 1909]

In full agreement with the cautionary anecdotes above. Smoke before the thermal cut out switched and without the slow blow fuse blowing is a large alarm bell going off and 'near miss' warning. Not an area of boat maintenance where being 90% sure of what you are doing is sufficient. Regardless of your own perception of the risk, a close quarters fire in a marina (where it's most likely to happen) won't affect just your boat ...

At minimum I'd want to check that the winding insulation hadn't been damaged by the overheating and change the brushes while at it.