Today’s invention is an alternative to the container ship.
Containers would be made individually watertight, lashed together in the shape of a hull and propelled by several dispersed containers each containing a large electric motor and propellor.
Many such containers would travel below the water surface and a small set of them would be used to create crew quarters on the uppermost face of the ‘vessel.’
I thought this was very interesting http://www.wired.com/business/2013/08/qq_containership/