Thanks Geoff and MTurpin,
Yes I did feel like the 2822 brushless would be a bit overpowered, but that’s what the manufacturer suggest. I’ve got no experience to base the motor size on, there doesn’t seem to be any specs listed for the props stating required torque or anything else that would help choose a motor. I know how to work out speed from prop pitch, but no way to work out how fast a given motor will be able to turn the prop.
I was surprised at the watercooling also, I’ve run many Tamiya cars with their own ESC and 540 Motors, and that only has a heatsink which is fine even when it’s deep inside the bodywork.
However it seems marine brushless ESC, even only a few amps, all have watercooling.
Geoff the AeroNaut kits look really nice, the quality of the build instructions put the Sea Nymph kit to shame! Those HAKits look interesting too. One issue with the Sea Nymph is the tiny area at the back for the rudder servo - does your Morston have the servo at the back end? I’m thinking about moving the cockpit aft bulkhead forward to make more space for the steering gear, and fabricating a hatch for the aft end so I can still get access.