Bow thruster brushes

[Simpo Two]

For a ling time my boat's bow thruster has been pathetically weak, and an engineer has diagnosed the brushes to be the problem as opposed to voltage drop.

Vetus have told me I need these: https://vetusonline.com/english/categories/thruste...

- but the price seems barking for a few bits of bent metal. Is it possible to buy an equivalent 'aftermarket' product anywhere?

[SamR380]

I offer no guarantees, but I just searched for carbon brushes with those dimensions:

https://www.amazon.co.uk/13-25-Electric-Forklift-G...

[Chippo1]

Plenty of specialist carbon brush manufacturers in uk , who can supply all shapes and sizes , at this moment I can’t remeber who I used at work for brushes for big DC machines , something carbonate or morganite , did all sorts and one offs., Google is your friend !

[GliderRider]

If you can salvage the clock springs, these brushes these brushes appear to the same dimensions. OK, they're 0.5mm longer on the length, but you could file that down if necessary.

These cheaper ones have a slightly different shaped connector, but the same size brushes.

Having worked on industrial slip ring assemblies, a word of advice. Do not use any silicone products (grease, rubber, gaskets, sealants etc.) anywhere near carbon motor or alternator brushes. The silicone reacts with the carbon, causing greatly accelerated arcing and erosion of the brushes.

This illustrated guide by Morgan Advanced Materials, allows you to diagnose brush and commutator issues by looking at the mating faces.

Edited by GliderRider on Wednesday 28th August 20:11

[Simpo Two]

Great replies, thanks all

I haven't figured out how to remove the brushes yet so I only have the mechanic's view that the springs aren't holding the brushes in firmly enough for some reason. Hard to believe the brushes have worn out... I really need to find a YT tutorial and photograph what comes out so you can see the full picture.

[GliderRider]

Simpo Two said:

Great replies, thanks all

I haven't figured out how to remove the brushes yet so I only have the mechanic's view that the springs aren't holding the brushes in firmly enough for some reason. Hard to believe the brushes have worn out... I really need to find a YT tutorial and photograph what comes out so you can see the full picture.

Simpo Two, If the brushes have worn right down, with some designs of brush holder then the springs may not be able to exert any pressure on them. It is just possible that if they have got really hot, then the spiral springs have lost the temper from the steel so they aren't working. These springs appear to be the similar size and width to the ones in your original link. The rest I found were not as wide.

Edited by GliderRider on Wednesday 28th August 20:45

[hidetheelephants]

Simpo Two said:

For a ling time my boat's bow thruster has been pathetically weak, and an engineer has diagnosed the brushes to be the problem as opposed to voltage drop.

Vetus have told me I need these: https://vetusonline.com/english/categories/thruste...

- but the price seems barking for a few bits of bent metal. Is it possible to buy an equivalent 'aftermarket' product anywhere?

Notwithstanding that the brushes may well be shagged; how old is the bow thruster installation? Is the prop clean? Occasionally frequenting boatyards I see a few caked in so much antifouling it's a wonder they produce any thrust at all.

[Simpo Two]

hidetheelephants said:

Notwithstanding that the brushes may well be shagged; how old is the bow thruster installation? Is the prop clean? Occasionally frequenting boatyards I see a few caked in so much antifouling it's a wonder they produce any thrust at all.

New in 2012 when I bought the boat, so I know exactly how much use it's had. 'Not much in the scheme of things' I would say.

Boat's had Coppercoat not antifoul so apart from maybe some weed, no antifoul. It had fresh Coppercoat a few months ago, no issues seen. The bow thruster's been largely ineffective for some years; it just gives a pathetic whine and barely moves the bow.

[GliderRider]

Simpo Two said:

The bow thruster's been largely ineffective for some years; it just gives a pathetic whine and barely moves the bow.

Simpo Two, Are you absolutely sure that the rotations on the motor match the expected rotations of the propeller? Maybe a shaft is slipping somewhere?

[Simpo Two]

GliderRider said:

Simpo Two, Are you absolutely sure that the rotations on the motor match the expected rotations of the propeller? Maybe a shaft is slipping somewhere?

After the mechanic fiddled with the brushes/springs, it worked properly for a short while.

I'll drop him a line, as he's seen the gubbins and I haven't, and ask whether I need brushes, springs or both.

[ferret50]

Proper helm's do not need bow thrusters!

[Simpo Two]

ferret50 said:

Proper helm's do not need bow thrusters!

Agreed. But sometimes I have crew that can't push a boat out, or it's just me, or there's a wind blowing me on, or I'm in a line of moored boats. With the bow thruster useless, the other plan is to use the stern thruster and reverse out

[Simpo Two]

Yesterday after boning up on videos showing how to remove Vetus thruster brushes, I went up to the boat and set about it.

I found the springs - four of them - and started on one.



The spring was easy to pull back with pliers, but the brush wouldn't shift or even budge. I pulled as hard as I dare on the wires, nothing. So much for my plan to measure the brushes.

Then I noticed a copper-coloured ring of thick wire running round half the diameter of the motor and engaging with two of the brushes. But only two. What's that for, and why only two?



That would make two of the brushes even more impossible to remove, so I'm stumped.

[LimmerickLad]

ferret50 said:

Proper helm's do not need bow thrusters!

True but could be a saviour of many marriages............that may just have been mine and Mrs LL's though

[Simpo Two]

Anyone? Or is this a job for the Vetus technical dept?

[GliderRider]

If we could see a bit more of the motor, it would help identify it. Can you remove the whole motor from the housing?
Maybe be that the thick copper conductor on one side should have a twin on the other side? That could be why it doesn't work properly, as its not getting the current it should if one of the brushes isn't doing anything?

Maybe ask on a boating forum, or around the marina if your boat is in one, to see if anyone with the same model of Vetus bow thruster could show you a photo of the the top of their motor?

Edited by GliderRider on Monday 9th September 21:38

[Simpo Two]

Thanks for the thoughts. This is the side view:



I don't have the knowledge to remove the motor. I could unscrew everything I see but something might go horribly wrong. But it does seem odd that the copper wire isn't symmetrical. Does it conduct electricity, or act as a secondary spring?

I think I need to talk to Vetus.

[markcp]

The silver cap over the top of the whole thing looks to be held on with those couple of screws so could removing that shed any more light on the lack of symmetry?