The term "submersible infrastructure" comes from the final draft script of "Azati Prime", which repeatedly referred to the facility as a "gigantic, submersible infrastructure".
John Eaves did some design work on the submersible infrastructure. "The idea was big and the technology was to reflect a submerged ship yard with multiple layers of cabling, lights, and construction vessels working round the clock to get this bomb ready for delivery to Earth," Eaves recalled. He illustrated an initial version that "was brutally rejected, and stripped down to a few not so exciting simple frame work ideas," in his words. Eaves went on to remark, "I believe Doug [Drexler] wound up finishing this one up and his versions also were taken down to bare minimums. So despite it’s 4F rating I still liked how it turned out and it now is a fav in my Portfolio." [1]