The JIM walk off Oahu

Sylvia Earle · 1979 CE · Earth

The JIM walk off Oahu — Sylvia Earle · 1979 CE · Earth — Recorded expedition route · schematic map

Carry a scientist to the sea floor in an atmospheric suit and release her to work untethered.

Historical context

A diver breathing compressed air can stay only about twenty minutes at thirty metres without decompressing, Earle explained, and after two weeks living fifteen metres down in the Tektite habitat in 1970 her all-female team had needed 21 hours of decompression. The JIM suit sidestepped the problem by keeping one atmosphere inside a jointed armoured shell. Such suits were normally lowered on a cable; for Earle's dive off Oahu on 19 September 1979 the suit rode on the front of the submersible Star II and was released on the bottom at 381 metres, joined only by a communication line to the submersible. She spent about two and a half hours walking and looking. Guinness World Records lists it as the deepest untethered sea walk by a woman; tethered suits have since gone deeper.

The voyage, step by step

  1. A suit shaped like a man

    1979 CE

    In September 1979, on Oahu, the team readies JIM, an armoured suit of cast magnesium with oil-supported joints that weighs about half a tonne with its occupant and keeps one atmosphere inside.

  2. Off Makapuu Point

    1979 CE

    The dive site lies off Makapuu Point, some six miles offshore by Earle's recollection, about ten kilometres, where the bottom is about 380 metres down.

  3. Strapped to a submersible

    19 September 1979

    On 19 September 1979 Earle, sealed inside JIM, is strapped to the front of the small submersible Star II, which carries her down to the bottom.

  4. Two and a half hours at 381 metres

    19 September 1979

    Cast loose from the submersible, Earle walks the sea floor 381 metres down for about two and a half hours, with no line to the surface, and plants an American flag.

  5. A coral that catches fire

    19 September 1979

    Among spiral bamboo corals taller than she is, Earle touches a living colony and watches it flare with blue light, rings pulsing along the spiral.

  6. Straight back to the surface

    19 September 1979

    Back aboard the submersible, she rides up with no decompression stops, because the suit has kept her at surface pressure throughout; at the surface her colleagues' questions crowd in.

Outcome

About two and a half hours at 381 metres on 19 September 1979, which Guinness World Records lists as the deepest untethered sea walk by a woman; atmospheric suits on a tether have since gone deeper.

Sylvia Earle

Marine botanist who walked untethered on the sea floor off Oahu at 381 metres in 1979, the walk Guinness World Records lists as the deepest untethered sea walk by a woman.

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Sources

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