80100 direct cooling


Any data , rpm , amp … With this propeller ? Thank you


So Mat, you’re saying that if you had it to do over again you’d use 2K rather than epoxy the motor?



nono, epoxy works great to fill the gap…
but I had to use something else to cover the magnets… epoxy was just in between…


That is a good choice mat :wink:


I do not have any rpm logging but running 12s I need 58 amps to get on foil and 45 amps once up on foil to maintain. This is on a naish large surf foil wing.


Looks like your amps and watts were no longer showing up with your rpm at the end and your speed stayed super low even though you had some spikes. What speed do you first have the ability to pop to foil (start foiling)? What speed is your remote set to and how fast can you pop it up? Do you believe you could tow a foiler also without fire?
On a side note what gauge is your motor and batt wires to and from esc were they hot when you opened up? Thanks for the data looks super fun.

I recommend a smaller wing for your total weight, do you know it?


The low speed no amps at the end is when i had to swim back to the beach :slight_smile: the system was still powered, so the GPS was on, but the controller low voltage limit keep it either off or at very low amps…
I think it starts popping up in the 15-16 km/h…once up i tried to slow down as much as i could, and it stayed foiling at 13… but not very stable and if you touch the water, it’s over…

My remote has some kind of cruise control: there a dead man switch, and with your thumb you control acceleration (up and down), i have a max range issue to look at (seem to be looping back to 0 when i go full on… ), but i don’t set the speed by itself.

The problem with towing someone would be more the stability… may be with some practice… my board is huge, so i don’t use much more power when i’m touching the water compared to flying…
if you tow a sup with a foil, it should work fine i guess …

My wires are: 8 AWG Silicone Wire / 1650 Strands of Tinned Copper Wire.the were completely cool when i got out… the only thing that did heat up was the batteries…
Actually even the elogger wire that are much smaller and see the full current were not warm…

For the wing that’s my plan for next test: go back to the original foil-fish wing… but i’ll also have a new prop to test… I’ll do my best to convince myself to get back to the beach to switch either the wing or the prop to get more useful data :slight_smile:


Hi @Mat. HAve you considere to implement a duct for your propeller?

Hereby an example of a propeller + Duct:


I think this would have a significant impact on the Thrust transmitted to the water, consequently an increase on the system efficiency (could increase batteries autonomy)

Best Regards


Most guys here seem to conclude that a duct increases efficiency only at low speeds, at average and high speeds it introduces too much drag and reduces efficiency.


And a duct would be a pain to attach… the whole body of the motor rotates, so you’d need to go as far back as the clamp on the mast.
That would be easier if I finally take the time to design propeller that fits around the rotor but that would make the diameter that water has to go around even bigger… so I think for now I’ll stick to commercial props. My next improvement would be to make a smoother transition between rotor and prop.


Can you sen the link of your propeller?


How they made such conclusion?


That’s how I solve the mounting:


What prop is that and does the mounting bracket come with it, I’m in the process of gathering parts.


Hi, this is a cheep alu prop from ebay. You can find it about 12€.
(7 1/4X5-A Boat Propeller Aluminum)
It has to be milled and drilled a bit, but was not difficult.
The mounting bracket is self made alu.


Does anyone now, where i can get the 3D data of this prop and its hub? I would like to print perfectly fitting hub substitution over the existing hub, so please do not answer with javaprop. Also i would need the hub geometry of the 7 1/2 " yamaha props. Any idea where i can get this?


Would this give you a good start https://grabcad.com/library/outboard-propeller


This mount fits inside the bottom profile of the 7 1/2" outboard props so you can directly mount it to the C80100 motor without any modification of the propeller.


Hope it helps.


Yes Ducts are good for slower speed 6-10mph after that they cause a lit more drag, but they play a safety roll whichnis citical.

Propeller driven surfboards are ban/illegal in canada and likey other countries as well because they are unsafe for the riders and thoae around then. The new lift efoil with open prop is nit allowed in Canada and likey pulled off the market as soon as someone get chopped up.

It would be a much larger pain getting chopped up at sea then spending months recovering physically and mentally.

Open props are going to kill the sport, its that simple.


Hi, you say that you have 40ah 12s, what kind of battery is it? can you show it?