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3 Motors RC Boat

I have a RC boat with three brushed motors and I would like to change it to Brushless

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William Dawson 114/07/2020 11:04:16
6 forum posts
5 photos

Hello All

I was hoping to get some help with how to set up a 3 brushless motor configuration for my RC Boat. I've had this boat since I was 12 and it was sat in my loft for 10+ years. Recently I've taken it down and decided to an upgrade! I'd like to do a 3 brushless motor setup but I do not how I would do this. I used to race RC Cars so I understand ESC, Servos, Radio receiver and the rest but I've never attempted to go more than one motor. How would I go about fitting 3? Appreciate all help and Feedback! Can upload pictures of the boat if it helps with the thread. Look forward to any and all responses!

Thank you

harry smith 114/07/2020 11:34:38
1034 forum posts
1282 photos

Hi William

Can we have more info on the boat, size, props please.

With brushless motor you require a ESC for each motor for a start and a set of Y leads to connect them together to run of one channel.

The brushless motor are far more powerful than the brush motors.

I found that out my dropping a 35mm 2400kv one into a RC car(the old motor was a hot 540).

So on 2S Lipo I had 17280 rpm but a power jump from 90 Watts to 550Watts( dam fast).

I have had it on 3S (26640 rpm) and it's totally insane !!!!

So watch the power ratings with three in one boat !!!

Harry Smith

Byron Rees...(Ron)14/07/2020 13:38:55
99 forum posts

Hi William,

You should have very little trouble swapping 3 brushed for 3 brushless motors in your boat. I have now done this to nearly all my models (26 of them!!!) As Harry (above) says you will need to buy a separate speed controller for each motor, so it is vital that we know what the ,model is, what the current motors are, and if it went OK with them or not, or even if you don't know.

A brushless motor equivalent to what is in it at the moment will be quite a bit smaller but may fit the existing mounts which will hopefully maintain the propshaft to motor line-up.

You will have to solder up a three way lead from the receiver to power each controller, as I have never seen one supplied ready made (I could be wrong) This is unless you want the two outers paired and the middle one on a separate stick, as in say...some torpedo boats.

So once we get some actual details of what we are playing with here, we can all make suggestion which will hopefully help you.


Kip Woods14/07/2020 15:47:13
265 forum posts
35 photos

Component Shop do a 3 way splitter lead.

William Dawson 114/07/2020 17:54:23
6 forum posts
5 photos

Hi All!

Already the responses are giving me some interesting potential ideas to turn this into a speed demon!!

The images attached below show the boat in question as well as its current setup, in my opinion, it's a pretty rubbish setup. It was essentially a kids toy in all fairness but I can just see it being far superior to this. I can see it being modified such as cutting some of the plastic away to make the hatch bigger and more accessible as well as to get more space as well. I'm not scared to modify it as I'm an engineering student and worked in Motorsport for the past 4 years now so I'm not afraid to get properly stuck into it.

I am grateful off the feedback given and I think I will now start to build a plan of how this is going to be built, my only worry really is the material the boat is made off. it's like a 3/4mm thick plastic and what worries me is that any bigger motors may just churn the plastic up and ultimately sink it! which obviously something that must be avoided.

Anyway, I look forward to more responses and will be very appreciative all of your thoughts and feedback!



ashley needham14/07/2020 19:26:53
6572 forum posts
144 photos


I would be inclined to rip the lot out and fit just one motor.

Would be adequate and save a fortune on esc, leads and motors.

As it is configured, I could see the outboard prop cavitating as it goes into a tight turn.


William Dawson 114/07/2020 20:14:53
6 forum posts
5 photos

Would cavatation be a issue for RC boats? What if the propellers were metal?

Colin Bishop14/07/2020 20:33:16
4508 forum posts
6059 photos
398 articles

I would agree with Ashley One motor would give you all the perfornance you need and far cheaper.


Edited By Colin Bishop on 14/07/2020 20:33:53

ashley needham14/07/2020 20:47:02
6572 forum posts
144 photos

I will stick my neck out and say that virtually ALL fast r/c speedboats (this sort of hull) use single motors/props.

You might want two or three props for specific scale torpedo boats etc, but otherwise....

Cavitation can affect all prop sizes big or small.

Your boat has three props as it is a ready-to-run type and it looks sexy in the packaging. Lots of RTR boats have two props, but they do not have rudders, control being by differential prop speed (cuts down costs).

Some of these hulls are very nice and can be made to go very well with replacement motors.


Edited By ashley needham on 14/07/2020 20:47:29

Edited By ashley needham on 14/07/2020 20:49:17

William Dawson 114/07/2020 22:32:42
6 forum posts
5 photos

Ahh okay noted! In that case I suppose what I could do is cut out the middle prop and fill the gap to smooth it out and then replace the 2 outer props with new motors. Would a rudder be better to use in that set up?

I understand that one prop can give good performance and it will be cheaper but to be perfectly honest I'd very much like to turn this into a speed machine! Just a speed freak personally

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