lights and 3D cameras so James could record his historic dive
in vivid detail.
The vessel was designed to make repeated dives, but,
after completing just one mission to the Challenger Deep and
suffering some damage, Cameron donated it to the Woods
Hole Oceanographic Institution, in Massachusetts in the USA.
In 2018 the Australian National Maritime Museum in Sydney
hosted a collection of objects from the Deepsea Challenger project,
which recognised Australia’s significant involvement in deep
ocean research.
While the technological change from Tr ie ste to Deepsea
Challenger took 52 yea r s, the nex t leap, to Limiting Factor, came
i n on ly si x. It s pressure sphere is m ade f rom t it a n iu m, not steel,
and it’s large enough to seat two people in relative comfort.
Designed and manufactured to be fully reusable, it’s the only
submersible to gain Full Ocean Depth (FOD) commercial
certification.
This means it can safely carry passengers, scientists and crew
to any part of any ocean. It’s why Limiting Factor is perfectly
suited to reaching the bottom of the world’s oceans like no
vessel ever before.
A moderately sized mother ship, plus a launch-and-recovery
system and support team are needed, but the science and adventure
possibilities are endless. The unexplored territory in deep ocean
trenches is estimated to be about the size of Australia.T
HE FIRST OF THE Five Deeps to be achieved was the
Atlantic Ocean’s 8376m Puerto Rico Trench, which
Victor reached on 20 December last year. This was
swiftly followed by the Southern Ocean’s 7434m South
Sandwich Trench on 3 February 2019. The third was the Indian
Ocean’s 7192m Java Trench on 10 April this year. The Challenger
Deep in the Mariana Trench was the fourth. And the final
and fifth record was to be broken as we went to press, when
Limiting Factor was expected to head to the bottom of the Arctic
Ocean’s 5670m Molloy Deep.
The Southern Ocean expedition was the most challenging in
terms of remoteness and weather. The South Sandwich Trench
is about 850km south-east of South Georgia, which is itself
1390km from the Falkland Islands. Most of the South Sandwich
has never been sonar-mapped, so the goal was to thoroughly
map the trench before diving to its deepest points.
The expedition’s mother ship is a 68m ex-US Navy Stalwart
class Cold War submarine hunter now called DSSV Pressure
Drop. Its quiet diesel electric motors permit communication
between the surface and Limiting Factor by using high-tech un-
derwater acoustic communications systems.
The wild card in any Southern Ocean expedition was always
going to be the weather. Compounding already sub-zero air
temperatures, the high-speed westerlies of the Screaming Sixties
whip up monster swells and a vicious wind-chill.September. October 101Dr Alan Jamieson holds amphipods retrieved from the
science landers that supported Limiting Factor in the
South Sandwich Trench. A Kongsberg EM124 multibeam
sonar image (below) of the trench shows the deepest points
highlighted in purple.Above the Mariana Trench in the Pacific Ocean,
Tim MacDonald prepares to disconnect Limiting Factor
after its launch from the stern of DSSV Pressure Drop.PHOTO CREDITS: TOP, GLENN SINGLEMAN; BOTTOM; TAMARA STUBBS