It reminds me of an updated version of a vehicle that one can buy plans for from RQRiley. http://www.rqriley.com The at RQRiley is enclosed and gets fresh air from the surface from one of the pontoons that stay on the surface and used air is expelled via the other surface pontoon. It is electric powered. It has emergency ballast that can be dropped in case one needs to get to the surface.

This is an interesting concept and it could be a lot of fun to use. Two key points would concern me, however:
1) Unprotected propellers could be very dangerous to divers and indeed to the crew themselves if one were to to become dislodged from the craft.
2) I would worry about a craft controlled solely from underwater with no controller or 'lookout' above water. Distracted divers could crash the craft into other surface objects (including swimmers). Also they would be unaware of any other approaching dangers at the surface. (e.g. a jetski)
Perhaps if these points were addressed the Platypus could soon attract a big following.

Hi Alien
the craft in this article is the prototype: we will announce soon the final version that will be equipped automatically with a 360° vision system from underwater and protected propellers
We do not want to take any risk regarding safety of passengers and drivers !
Thanks for your interest
FAB

Like the idea - places that have calm-water coral reefs would buy dozens for gentle underwater viewing platforms, without disturbing the reefs. I hope they have some sort of "early warning system" to avoid running out of air compressor power / fuel.

Hi "The Skud"
yes the air compressor as the hydraulic system is running on electric energy. The batteries for these systems are AGM type, the most reliable one, and a warning system (just a waterproof led) is indicating on the nacelle low level battery. Also the air compressor is equipped with an air reserve used on many hookah systems to more the breathing more comfortable and for safety reasons: we used this model in order to avoid any issue.

The heads of the divers seem to be about 1m under the water. Why not just have a glass bottomed boat? A central narrow section of the boat could project say 1.5m downwards with windows in the sides. You don't even need to get wet! No problem with air supply. If you really want to be in the water, why not get towed behind the boat on a rope whilst holding a hydroplane to control depth?

This thing will not have much of a shelf life considering once our oceans are lifeless due to overfishing, agriculture runoff dead zones, plastic gyres, coral bleaching and Global Warming caused acidification there will be little to see underwater.

Mass produce, awesome, must for worldwide

I'm a diver and I love powered flight, this is cool idea, might be used in conservation.

I beg to differ about this being the first such craft. In Ft. Lauderdale in the late 1950s a small shop built a sub by slicing the top off of a torpedo and installing seats one behind the other. The vehicle occupants used scuba for their air supply but a Hooka rig could have easily been used as well. The hand built units had the advantage in that they could go deep as well as shallow. I think they were battery powered. The builder wanted about $2,000 at the time and back then that was a lot of money.