The Navy built two DSRVs with 3 stainless steel balls connected and a fiberglass skin and I heard there was a Set for a Third vehicle!?!
Not sure of it’s rated depth——
Probably CLASSIFIED.
THE GREEN PICKLE was a Gem !
Avalon and Mystic were Decommed afew years
Ago.
The stainless steel balls are the pressure vessel. The fiberglass skin covers the skeleton and external equipment only.
The Navy isn’t stupid ... unlike the people who built a submarine out of carbon fiber ...