The JIM suit Atmospheric diving suit

a jim suit on display @ royal navy submarine museum, gosport

the first jim suit completed in november 1971 , underwent trials aboard hms reclaim in 1972. in 1976, jim suit set record longest working dive below 490 feet (150 m), lasting 5 hours , 59 minutes @ depth of 905 feet (276 m). first jim suits constructed cast magnesium high strength-to-weight ratio , weighed approximately 1,100 pounds (498.95 kg) in air including diver. 6 ft 6 inches (1.98 m) in height , had maximum operating depth of 1,500 feet (457 m). suit had positive buoyancy of 15 50 pounds (6.8 22.7 kg). ballast attached suit s front , jettisoned within, allowing operator ascend surface @ approximately 100 feet (30 m) per minute. suit incorporated communication link , jettisonable umbilical connection. original jim suit had 8 annular oil-supported universal joints, 1 in each shoulder , lower arm, , 1 @ each hip , knee. jim operator received air through oral/nasal mask attached lung-powered scrubber had life-support duration of approximately 72 hours, although actual survival time have been unlikely due thermal transfer through magnesium body.

as technology improved , operational knowledge grew, oceaneering upgraded fleet of jims. magnesium construction replaced glass-reinforced plastic (grp) , single joints segmented ones, each allowing 7 degrees of motion, , when added giving operator great range of motion. in addition, four-port domed top of suit replaced transparent acrylic 1 taken wasp, allowed operator much-improved field of vision. trials carried out ministry of defence on flying jim suit powered surface through umbilical cable. resulted in hybrid suit ability of working on sea bed mid water.

in addition upgrades jim design, other variations of original suit constructed. first, named sam suit (designated a.d.s iii), aluminium model. smaller , lighter suit, more anthropomorphic original jims , depth-rated 1,000 feet (300 m). attempts made limit corrosion use of chromic anodizing coating applied arm , leg joints, gave them unusual green color. sam suit stood @ 6 feet 3 inches (1.91 m) in height, , had life-support duration of 20 hours. 3 sam suits produced umel before design shelved. second, named jam suit (designated a.d.s iv), constructed of glass-reinforced plastic (grp) , depth-rated around 2,000 feet (610 m).