Today’s invention is an alternative to the usual submarine’s conning tower -an underwater crow’s nest.
To reduce drag and provide a higher observation platform, a minisub is located on a pair of streamlined arms as shown. The minisub has an airlock connection to the rear of the hull so that crew can enter and leave freely when in transit.
The minisub could detach from the hull, using the arms, and rise close to or high above the surface.
It might even be possible to have this vehicle detach completely and act as a lifeboat in an emergency.