Reducing amp draw

[Old School]

I do not quite get the hang of actually how much amperage draw rc boats consume. In my instance I am building a 1330mm TFL P1 Outerlimits as a brushless boat with a TFL Arneson drive. The motor is a 730 kv 56102 T20. The ESC will most likely be a Swordfish 300 amp model. The boat will weigh approximately 8kg when fitted RTR. Now my question. I want to minimise amp draw, so with say the boat setup for 10s (the motor is limited to 41 volts) and say a 60 - 62mm three-bladed (perhaps two-bladed) propellor, would the boat draw less amps on 10s than 8s, with no other changes made, please, assuming that there is not much difference in the weight of the batteries? Ideally, on 8s a slightly larger prop (perhaps two-bladed) would most likely be used, but in my example I am assuming that the same prop is used. My aim is a sport boat achieving perhaps 45 - 50 mph. Outright speed is not a factor.

[larryrose11]

Power = Volts*amps. double the voltage, half the current.
Going with the lowest KV and the highest battery voltage will keep the amps low, assuming you have targeted the right motor RPM.
if you assume 80% efficency, 730 KV motor on 10S will make 21608 RPM.
Since you are talking about using the same motor, it has the same resistance.
I (current) = Voltage / Resistance. going from 10s to 8S will draw less current for the same prop.
Increasing the prop on 8S will then raise the current, and the speed as well.
The actual numbers all depend on the instantons motor efficiency (which varies a lot from different manufactures), and prop efficiency (which also varies a lot) .

[Old School]

Many thanks