I love this: Swedish designer Milko Ozlu has created the specs for a human-powered submarine. It's kind of like a sealed, waterproof scull: Two people sit and row oars that jut out the sides of the craft, and which turn sideways with each forward sweep so they don't inadvertantly propel the craft backwards.

Back in the early 17th century, the Dutch inventor Cornelius Drebbel designed a similarly oar-powered underwater craft, which never caught on. Apparently Ozlu hadn't heard of the Drebbel sub when he began work on his creation. Ozlu was mostly just interested in repurposing the motion of sculling -- which is highly efficient and conservative of human energy -- in a new direction. As he notes in this interview:

"I envision the target group for Uscull as people who enjoy water activities, below or above surface," says Milko. "As the vehicle has clear parallels to scuba diving and rowing, users with either background could make a smooth transition into the Uscull. The underwater aspect adds a third dimension to rowing," adds Milko.

Heh. It also adds a new dimension to drowning, probably. Or maybe not: These things are designed to submerge only a few feet, so they might be pretty safe. More pix are here!

(Thanks to Erik Weissengruber for this one!)