No doubt someone has experience with brushless motors and their associated ESCs, but I tend to go with brushed motors. What is being described is "large tug boat" territory, so hunting around for threads covering these will help your learning curve. My personal preferences run to sail boats and small stuff, so the heavy end needs somebody else. An almost half-hundredweight boat probably weighs about as much as my current collection of boats.
The hulls, and anything else submerged, need to be pointy, to allow for the mass of water to be moved as gently as possible. The back end needs to be shaped so as to both allow the water to flow back easily and present a clean flow of water to the propellers. This will make best use of what limited power can be stored in the space available. Pushing a flat surface through wat takes a lot of power.
You should be looking for motors in the 7xx or 9xx range, preferably with either a high turn count (greater than 35) or pole count (5 or higher) or both. You should also be looking for large diameter props to give the ability to move a lot of water a relatively short distance in a given length of time (low speed, high torque) and a motor or motor/ gearbox/belt drive to drive it quietly. Conventionally, motor can diameter should be greater than the prop diameter, the motor pole count should be not less than the number of blades on the prop. Gearing lets a smaller motor drive a bigger prop and still stay within these limits.