Small Jet Craft - Motor And Impeller size

Build, Repair & Mod
,
1

Hi
I wanted to have a project for the next year or so, so I figured it would be fun to make a small electric craft for my kids. (The lake I intent do drive on do not allow fossil boats).

I have a 20s 67Ah battery that I have prev used for a tiny ev project. I was hoping to use to use this battery to power the craft. The local regulations says the max power output of the craft can be 10hp, so 7.5kW ish.
(I was hoping to keep the amp around 100 )

In addition looking youtube it looks really fun to play around with a jet drive, so I would like a design that uses a (single) jet drive.

With that being said, I was thinking of a small boat / jet ski hull. And my main concern is on the motor+impeller size choice.

I was looking at the 420kv SSS motor and a 60mm impeller. Would this be suitable for the type of setup? It dont need to have the best top speed, im more interested in a decent acceleration and high turn rate.
Also any other suggestions/ideas for this?

2

I have used a Rocket 5692 730kv with a 53 mm jet drive. At full throttle 200amps, I think low KV motors are not rated for high amps and you will need a big motor.
I`m no expert

3

Well, low kV motors don’t need high amps to create torque as the torque per amp is inversely proportional to kV.

If you want to calculate a drive roughly then propeller disc theory will probably get you close enough if you can do some maths, but probably quicker to check what mhz uses in their kits: