In 1952, began developing “podledno-transport” (under-ice transport) submarine Project 626 for troops in Arctic areas, as well as for air surveillance and communications while in the Arctic basin. It was supposed to put up to 5 tanks and fuel for them, or 165 people landing with weapons or ammunition and food supplies.

The submarine would pop up almost in any given area. It was equipped with sonar equipment, usage with sufficient accuracy to navigate underwater, and was assisted heater system for education in a piece of ice through holes for paratroopers to the surface through vydvižnuû shaft. Designers have proposed several options. The closest to the job acknowledgement, where normal displacement boat was 3480 tons, length was 100 m, width-9.5 m, draft: 6.6 m.