DCNS unveiled this concept, the SMX-24, at Euronavale in Paris.

It’s an all fuel cell concept, displacing about 3500 tons, which makes rather larger than the Diesel-Electric boats, but a rather smaller than most Nuke boats, it’s about the size of an Alfa class submarine.

It’s supposed to have 30 days endurance, whether surfaced or submerged, and it has a cruise motor at the rear of the ship, and sprint motors, as well as fuel tanks and weapons, mounted at the tips of stub “wings”.

This is not the first radical concept from DCNS, they also have the SMX-23, which was shown at last year’s Euronavale, and has since been dubbed, “Andrasta,” a small boat intended for littoral waters, which carries its entire weapons load outside of the pressure hull, so reloads can only be done in port.

IMHO, I think that the SMX-23 is far more likely to see service than the SMX-24.

While there are many different sorts of nastiness carried on board submarines, the idea of carrying large amounts of liquid oxygen and possibly liquid hydrogen, for fuel cell operations makes me profoundly uncomfortable.