The JIM walk off Oahu

Sylvia Earle · 1979 CE · Earth

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

Historical context

A diver breathing gas at depth must come back slowly, and below about a hundred metres cannot come back at all without hours of decompression. The JIM suit sidestepped the problem by keeping one atmosphere inside a jointed armoured shell, so that a scientist could be set down at 381 metres and picked up again like a parcel. Earle used her two and a half hours to walk, look and record, and nobody has walked deeper since.

The voyage, step by step

1. A suit shaped like a man

   1979 CE

   At Honolulu the team loads an armoured suit of cast magnesium with rotary joints, weighing half a tonne and holding one atmosphere inside.

2. Off Makapuu Point

   1979 CE

   A few kilometres east of the lighthouse the island's flank drops steeply, putting deep water within an hour of the harbour.

3. Strapped to a submersible

   1979 CE

   Earle is bolted to the front of the small submersible Star II, which carries her down and sets her upright on the bottom.

4. Two and a half hours at 381 metres

   1979 CE

   She walks on the sea floor a quarter of a mile down, untethered, planting a small flag and turning over the sediment with a gloved claw.

5. A coral that catches fire

   1979 CE

   She finds a bamboo coral spiralling out of the mud and watches it flare with blue light wherever her claw touches it.

6. Straight back to the surface

   1979 CE

   Because the suit never let the pressure in, she is lifted the whole way in a few minutes and steps out on deck with no decompression at all.

Outcome

Two and a half hours at 381 metres, a depth record for an untethered walk that has never been beaten.

Sylvia Earle

Marine botanist who walked untethered on the sea floor off Oahu at 381 metres, the deepest such walk ever made.

Read on Wikipedia

Sources

• Sylvia Earle — Wikipedia
• NOAA Ocean Exploration: hydrothermal vent and deep-sea archivesNational Oceanic and Atmospheric Administration

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