I've been designing a remote controlled submarine but I'm not sure how to remotely control it. All RC parts I've seen that transmit video, which is important, communicate at 2.4GHz. I would have thought that doesn't work underwater due to the microwave principle, seeing as water resonates at around 2.4GHz. However I noticed on some guy's website he had a video unit for a submarine that apparently operated at 2.4GHz. Anyone have experience with underwater video transmission?

Thanks

You have two choices.

1. Use a 2.4 ghz (or 1.2) wireless mini camera - as per http://www.caswellplating.com/models/camera.html

This kit has virtual goggles, so you are actually on board looking through the 'periscope' as you sail. The antenna is in the mast, periscope like, and will only work as long as the tip of the antenna is out of the water. You can record video through the rca jacks, instead of sending the signal to the goggles.
Or, if you want a higher definition, then get a wireless underwater camera from Oregon Scientific and record the entire dive onto a smart card. You can dive at any depth taking live video in better resolution than from the mini cameras.