Excellent Hydro, Thanks!
See, my point is I don't believe knowing what ESC, how it's cooled at what battery voltage, etc., etc. is a pre-requisite for motor selection. Sure, you need to have an idea of where going with these but a final selection is not necessary and could possibly change as one gets into this.
The airplane guys using brushless start with the prop. Basically what prop at what rpm to place the model in the speed range desired. Then they have a rule of thumb for the wattage. Basically so many watts per pound of model. The wattage per pound varies based on type of model/performance desired. i.e. trainer, sport, pattern, war bird, etc. And they go from there. It gets them in a good working ball park and experience then helps fine tune things.
From what I've seen the boaters could take a lesson from the airplane crowd.