Hi archistrage,
I think the easiest way to find support from other people is to visit the arduino forum:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl
I don’t see any problem in using an Arduino for your ROV, but in my opinion it would be much better to use a PicMicro microcontroller, as you will find much more support and material on the web…and unless you are an expert of microcontrollers, that would be a great benefit!
Good luck with your project!
rov_er