ROV controller?

I’m planning to build an ROV for use at the local lake. I’ve done quite a bit of reading on the subject and think I’m about ready to begin.
I’d like to control the system with two Basic Stamps, namely the BS2 or BS2sx. One stamp will be topside to drive an LCD and accept joystick controls. The second stamp will be subsea and needs to be capable of receiving data and sending data via the tether to the topside stamp. I’ve found a circuit that allows two stamps to communicate via two I/O pins on each stamp, there’s not much range though. I’d like to be able to reliably communicate as mentioned over a 150’ tether.
I’ll be using a live video feed on a dedicated coax so the BS2 won’t be handling any of the video duties.
I’ve read a little about the Maxim Max232CPE chip but am not sure if this will work for me.
Can anyone suggest a method and possibly provide a schematic to accomplish all this?
Thanks!

Have you checked out the open ROV project? Now that we have a laser cutting machine, we may try to make it in our spare time.