This Atmospheric Dive Suit (ADS) - named 'JIM' after pioneer ADS diver Jim Jarratt - made its maiden dive in 1971. The Royal Navy tested the JIM II from the HMS Reclaim, making 16 dives to 440 ft (134 m), as well as deploying the suit from an inflatable craft. JIM suits had six oil supported universal joints. The oil formed a perfect watertight seal and ensured movability. The hands on the ends of the arms were soon replaced with pincers. JIM had six plexiglass portholes and featured two independent oxygen rebreather systems for life support. Surface communication was arranged through an umbilical. In case of an emergency, this umbilical could be disconnected and the weights on the outside of JIM that assure negative buoyancy could be dropped by the diver so JIM would float to the surface.

JIM was involved in numerous successful diving jobs, including inspection dives for the oil and gas industry from 1976. Over the years, modifications were made to  JIM - particularly with respect to the joints of the suit, to allow for greater movability. The body was redesigned using fibreglass, and the four portholes were replaced with a massive dome. Depths limits with the latest model - the JIM IV now go to about 700 metres.