OpenROV

From the about page, "OpenROV is a
 Do It Yourself telerobotics community centered around underwater exploration and education. We have developed a low-cost telerobotic submarine that can be built with mostly off-the-shelf parts.
The goal of OpenROV is to democratize exploration by allowing anyone to explore and study underwater environments. The 
OpenROV community is also laying the foundation for globally-connected citizen scientists to share their data and findings."