I might be able to break my paralyzing fear of submarines if I could only ride in the Neptune MM2. Designer Vil Tsimenzin designed the Neptune MM2 as a nimble sea cruiser that can fit two comfortably.
The Neptune MM2 has a maximum depth of 750 feet and can hit up to 12 knots underwater. Tsimenzin's sub is unfortunately still a concept, but I am holding out hope that this bad boy will see the water one day. I'm coming for you, Aquaman.