Advice regarding Remotely Operated Vehicle (ROV) control scheme?
I suggest you take a look at the ArduPilot project, it's a board that can control Airplanes, Copter and Rovers. There have been some attempts to use it to control boats.

For controlling the motors I would use one COTS ESC. It's the fastest way to get a good way to have proportional control over the motors. But if you want you can design your own. But you need some specifications like:


the current&amp;voltage of your motors
the kind of motor
If you need to reverse the control.