Horribly impressive. My problem is not knowing what bits of kit are compatible with each other.
A bit like the Hitch-Hikers Guide, not totally accurate, but near enough.
The battery/motor/ESC rules are fairly simple.
The battery needs to fit in the boat, hopefully it will be capable of doing its job.
The motor should say that it can handle a few more volts than the battery can give. (safety margin)
The ESC should be able to run on that same battery. (same safety margin consideration)
Under load, the motor will draw current, the ESC should be rated to handle considerably more. (Honest rating, NOT 320A) Motors in parallel, even after adding together, need a bit more headroom as regards what the ESC will be able to offer them.
The load on the motor will be decided by the prop. Too much prop, motor becomes a heater and rapid battery drainer rather than a driver.
Simple prop rules
For any brushed motor on direct drive, the prop diameter should be smaller than the can diameter.
The prop should not have more blades than the motor has poles.
Gearing does change this, you can use a smaller diameter motor and/or a prop with more blades.
