It is a design for a faceted personal submarine. It would have what are essentially trolling motors on the end of each fin. The two from fins can be angled by the pilot to turn and even submerge the sub because of the V-like design.
While not shown in this first Google Sketch-up Design the sides of the sub would have ballast tanks that would make it neutrally buoyant so the motors could take over.
The windows would be supported by steel bars so that the large panes don't have to support the water pressure entirely.
This project could be changed to a pull behind sub, where it it is towed by a boat and the fins force it under the water. But then it would need to be a little sleeker. And the front fins need to be moved forward no matter what. So sue me I designed it in an hour.