JIM suit

NOAA

is recovered from the water

The JIM suit is an atmospheric diving suit (ADS), which is designed to maintain an interior pressure of one atmosphere despite exterior pressures, eliminating the majority of physiological dangers associated with deep diving. Because there is no need for special gas mixtures, nor is there danger of nitrogen narcosis or decompression sickness (the 'bends'); the occupant does not need to decompress when returning to the surface. It was invented in 1969 by Mike Humphrey and Mike Borrow, partners in the English firm Underwater Marine Equipment Ltd (UMEL), assisted by Joseph Salim Peress, whose Tritonia diving suit acted as their main inspiration. The suit was named after Jim Jarrett, Peress' chief diver.

The

In spite of the successful tests, the offshore petroleum industry still expressed little interest in the suit and it was not until 1975, when

Oceaneering

acquired DHB Construction and exclusive rights to the application of JIM suits in the oilfields, that the suit achieved success. This did not however please the British government, who after contributing money to the suit's development, did not want to see it being "given" to an American company over a British one. However, at the time, British diving concerns, most notably 2W, doubted the suit's abilities and therefore passed on purchasing the operating rights.

Its first commercial deployment was in 1974, when JIM suits were used in the recovery of lost oil tanker anchor chains in a Canary Islands harbor. In 1976 the JIM suit was used for a series of four dives on PanArtic's Hecla M25 well which were made through a hole cut in an ice floe 16 feet (4.9 m) thick, on which the rig was positioned, the first dive setting a record for the longest working dive below 490 feet (150 m), five hours and 59 minutes at a depth of 905 feet (276 m). In 1979, oceanographer Sylvia Earle set a human depth record of 1,250 feet (381 m) using a JIM suit.^[2]

The Arctic dives of 1976 proved that the JIM was capable of performing oilfield operations in very cold and very deep water; the average water temperature at the wellhead was measured at −1.6 °C (29.1 °F), while the average internal suit temperature was about 10 °C (50 °F). The operators needed no more than a heavy woolen sweater for thermal protection. The following year the JIM suit was used on over 35 jobs with an average duration of over two hours and in depths varying from 300 to 1,130 ft (91 to 344 m), and by 1981, 19 JIM suits had been produced.

The JIM suit and its variations enjoyed great success in the offshore oil industry for many years, although their effectiveness was hampered by the unwillingness of oil companies to install walkways around submerged sections of oil platforms. An experimental thruster pack that would connect to the existing JIM models was designed, but the suit gradually fell out of use with Oceaneering as their new

from Loch Ness in 1986, and were often used as back-up standby units for the rapidly advancing WASP suit. By 1990, the JIM suit was no longer commercially operated. Today, some of them may be viewed at museums across the world, along with many lightweight replica versions.

The JIM Suit is, perhaps, best known to the general public for its appearance in the James Bond film For Your Eyes Only, although it played a larger role in the 1989 sci-fi/horror film DeepStar Six.

For many years, a replica of the JIM suit was on display at the

.

Joseph Peress' Tritonia Diving Suit was the starting point for the design of the JIM suit, manufactured from cast

that Royal Navy divers had no reason to dive to the depths it was capable of. The suit was later retired, and eventually found its way to a junk shop where it would be discovered by Mike Humphrey and Mike Borrow in the mid-1960s. UMEL would later class Peress' suit as the "A.D.S Type I", a designation system that would be continued by the company for later models.

The first UMEL JIM suits, classified as A.D.S II, were constructed from cast magnesium for its high strength-to-weight ratio and weighed approximately 1,100 pounds (500 kg) in air including the diver. They were 6 ft 6 in (1.98 m) in height, 3 ft 5 in (1.04 m) in width, 3 ft 1 in (94 cm) in side width and had a maximum operating depth of 1,500 feet (460 m). Corrosion problems were countered through surface preparation and coating. The suit had a negative buoyancy of 15 to 50 lb (6.8 to 22.7 kg). Ballast was attached to the suit's front and could be jettisoned from within, allowing the operator to ascend to the surface at approximately 100 feet (30 m) per minute. The suit also incorporated a communication link and a jettisonable umbilical connection. The original JIM suit had eight annular oil-supported universal joints, one in each shoulder and lower arm, and one at each hip and knee. The JIM operator received air through an oral/nasal mask that attached to a lung-powered scrubber that had a life-support duration of approximately 72 hours, although actual survival for this time would have been unlikely due to thermal transfer through the magnesium body. As technology improved and operational knowledge grew, Oceaneering upgraded their fleet of JIMs. The magnesium construction was replaced with

on a flying Jim suit powered from the surface through an umbilical cable. This resulted in a hybrid suit with the ability of working on the sea bed as well as mid water.

In addition to upgrades to the JIM design, other variations of the original suit were constructed. The first, named the SAM Suit (Designated A.D.S III), was a completely aluminium model. A smaller and lighter suit, it was more

carbon fibre reinforced plastic

that would prove unsuccessful. The prototype failed at approximately 1,000 ft (300 m) when tested to destruction.

See also

• Atmospheric diving suit

• Curley MD,
  PMID 7135632
  . Archived from the original on January 13, 2013. Retrieved 2009-02-13.
• Nuytten P (1998). "Life support in small one-atmosphere underwater work systems". Life Support Biosph Sci. 5 (3): 313–7.
  PMID 11876198
  .

External links

• History of JIM suit
• The Joseph Peress Diving Suit
• Then and Now: Atmospheric Diving Suits