Boat Thruster Build

Hey Guys,
Seems like a knowledgeable community here!
I’m looking to build a boat thruster system using the same type of brushless motors you guys are using and figured I would ask for advice here before starting on it.
Basically looking to mount 2 motors under the swim platform of a wake boat for stern thruster use.
The smaller the better but I need a relatively high thrust to get a big heavy boat moving.

I’m thinking something along these lines:

But am open 100% to other options, not a lot of info out there about these things.

My thought it to run 2 motors and a controller to run one in forward and one in reverse (facing opposite directions) to get equal thrust both directions.

I would love to run it directly from the onboard 12V batteries but I’m thinking it may be easier/ more effective to run a lipo and then keep it topped up using the boat batteries and an inverter.

Again open to any and all ideas!

Hi,Are there any of the following that can meet your needs?
I have a thruster system that includes ESC and remote control launch and reception.




How much thrust is created by the top motor you posted?
price?

Any reason not using dedicated bow or stern thrusters? I have a Lewmar T140 /2.0 KW, 37kgf, it was not that expensive, very sturdy unit, then you can use the boats own battery. MUCH much safer this way, and in the long run probably also cheaper. That model is a bow thruster but would not be hard to modify for use as a stern thruster.

A few reasons:
The boat warranty becomes void if you put a hole large enough for a stern thruster in the hull. Not a huge deal but stops a lot of people from doing it.

It’s a surf boat with a surf pipe so traditional thrusters only really work in one direction well as they are blasting into a fixed object (the exhaust pipe) in one direction.

Very little room on the rear transom due to trim tabs and surf tabs. These small motors can attach to the swim platform brackets.

Supra came out this year with basically the idea I’m looking at here and I’m curious how they have done it. To my knowledge they don’t have a battery pack in the boat other than 2 large 12v.

.

Ah…ok, now i get it. Did meant to install the thruster outside the hull but under the swim platform, but there is so much stuff You would need two… how about throwing in a couple of trolling motors ?

Too big with not enough thrust.
These little efoil motors are the best option I have come across thus far.
I would love to find one that runs on 12v with higher amp draw as wire size isn’t a concern but I haven’t found anything yet.
Goal here is to make an affordable diy solution and potentially sell kits.

If you’re familiar with the wake boat world everything is sky high just because they can. Thrusters at the moment are a 10k+ factory option. And aftermarket is nonexistent except for one brand that’s about the same price and voids the hull warranty. 10k on a new 150k boat is not the end of the world but for someone with an older boat that still wants the functionality it’s out of reach.

Also to clarify I have a full CNC machine shop so fab work isn’t an issue it’s just finding a motor that will do the job and a means of controlling it.

OK, that’s a challenge. Still believe torque wise using a modded bow thruster with waterproofed engine(so the whole unit can be in the water) might be a durable solution but bulky. The hobby class motors here might struggle with longevity and torque in that application. How about a 80mm outrunner with min 12mm shaft, waterproofing is still tricky?

Bulky won’t work unfortunately.
I obviously haven’t tested any of them yet but in my eyes the application is much less demanding than a foil, they would be run in 5 second bursts around the dock, not for 30 minutes at full tilt.

Supra is doing it, but I haven’t seen the new boat to see what they are actually using.

OK, then yo really need another solution. This one has a 140mm tunnel, and even if only 2KW, the motor is huge…13kg weight of the kit. Close to 170 amp as 12V only.

Exactly, like I said not interested in that solution.
Look at the photo I posted above, they are clearly using these small motors effectively.

Here’s a closer look at the motor they are using:

something like these

I actually have that one sitting in my office it’s waaaay bigger than it looks in the photos and won’t work.

Does the thruster run without the main motor running? If not then I bet they using a converter to boost the voltage for those motors.

*I have just found out they are running the thrusters at 24V

And here it is…

https://www.amazon.co.uk/Dilwe-Underwater-Propeller-Waterproof-Brushless/dp/B07S23LN48

Man that does look really close doesn’t it! Thrust seems low for the application though no?

Probably a smaller version…

But if you scour the net for 24V thrusters you might find the right one.

That’s what I’ve been doing that brought me here actually.