JIM is a one-person atmospheric diving suit (ADS) named after the first diver who used it - Jim Jarrett. The JIM suit greets visitors as the first exhibit when they step into the museum.
Designed in 1969 by Mike Humphrey and Mike Borrow (partners in Underwater Marine Equipment Ltd.), the JIM suit was revolutionary because it kept the diver at surface pressures and allowed for deep dives up to 2,000 feet. The hard magnesium shell stands 6 ½ feet tall and weighs approximately 800 pounds, with articulating arms and legs.
While the diver could not walk far, they would be dropped directly on a worksite and would use their hands to manipulate the claws. The JIM suit was particularly effective in very cold and deep waters that were previously unreachable.
In 1974, JIM suits were first commercially deployed to recover anchor chain in Canary Island Harbor, and in 1976, they were used in the Artic to access wellheads. Also in 1976, the JIM suit set a record for the longest working dive below 490 feet (150 m), lasting five hours and fifty-nine minutes at a depth of 905 feet (276 m). By 1981, a total of 19 JIM suits were produced and used on more than 35 different diving jobs with an average of over two hours at depths from 300 to 1,130 feet. Multiple depth records were set by divers operating the JIM suit.
Most diving suits are ambient pressure (“soft”) suits that protect their wearers from the cold and surrounding environment, but not from the pressure of the water. At extreme depths, an atmospheric pressure (“hard”) suit like the JIM suit maintains surface pressure internally, insulating its operator from environmental pressures and eliminating the need for decompression after a dive.