Official Pi-Sub thread.
Continued from RasPI Idea/Project thread.
Having the pi down that far would mean the wifi would defiantly need a floating antenna, or to be tethered to a wifi router via CAT5. You get lots of signal attenuation from having a long cable reaching to the antenna (http://www.antenna-theory.com/phpbb2/viewtopic.php?t=351&sid=abdd60c0640e85cebc7c370af07b0c11), so floating WiFi with separate battery might be the way to go. I have a few that I got at various garage sales for $1 or less that could be donated to the project.
Not sure how one would mount motors for controlling props for locomotion. A few seconds on google suggests a greased shaft fitted through tight washers.
Another cool thread on waterproofing and RC subs. (http://www.rcgroups.com/forums/showthread.php?t=1212930)
Now we need a 3D printer and some injection molding equipment to make all this pretty :)
Maybe to start with we can just straight tether the rov to a laptop with CAT5 and then (in phase 2) create a floating WiFi platform. You could have a big roll of cat5 on a crank and just roll it out or in to retrieve the sub.
I think we can make one out of PVC although having a 3d printer would be awesome.
We could also use bilge pumps as jet engines or if the rov is smallish the motors off motorized fishing lures.
I like the lure idea.
I think they are built to work in water too. No need to water proof. No idea on cost though.
My own Raspberry Pi and Pi Camera are on their way!
Received my Pi and Camera in the mail today. Haven't had time to try it out yet due to having to write a job application for my own job but I can say that the camera is TINY.
Here is an interesting little discussion on the topic. Complete with people telling them why they did it wrong :)
https://www.reddit.com/r/DIY/comments/6qflp1/diy_submersible/
Gallery linked at the top of that page.