Science et Environnement

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Polar Pod to explore southern waters

Science et Environnement

As is his wont, intrepid adventurer, scientist, doctor and sailor Jean-Louis Étienne is planning another madcap expedition. As usual, the project is innovative and technologically audacious in addition to presenting a rare opportunity to advance our understanding of the planet’s still little understood Southern Ocean. The programme is called the Polar Pod Expedition. And what an odd vessel the Polar Pod is. Essentially, it is a manned observatory perched on the end of a long spar designed, like a spar buoy, to float vertically while drifting unassisted by mechanical propulsion for months with the Antarctic Circumpolar Current, or ACC. The scientists on the Pod will use this advanced observation post to collect samples of seawater at regular intervals over vast swathes of Southern Ocean. To date, sample collection in this part of the world has been confined to the occasional ship, oceanographic campaigns and various bases in Antarctica and France’s southern and Antarctic territories, supplemented by laboratory models using satellite data.

Scientific cornucopia

The programme launched recently by Jean-Louis Étienne aims to gather in situ measurement data in a major ocean current while offering an array of opportunities for science. Why? One reason is that the ACC is a major absorber of atmospheric carbon dioxide, a factor that has a direct impact on currents, plankton and other aspects of marine biology, which, we now know, affect the ocean’s natural balance. As part of the preparations for his many previous expeditions, Jean-Louis Étienne got to know a number a leading scientists working in these areas. The benefits of the programme for climatologists, currentologists, oceanographers, marine biologists and others working all over the world, including CNRS and Ifremer laboratories in France, are such that all are prepared to send volunteers to sea in the Polar Pod.

 

 

Designed in Lorient

The Polar Pod was designed in Lorient, on the south coast of the Brittany peninsula, by Ship ST. Laurent Mermier, the CEO and an experienced naval architect, has known Jean-Louis since his expeditions aboard the ice-resistant aluminium-hulled schooner Antarctica — now the Tara — built by the SFCN yard at Villeneuve-la-Garenne and aboard which he began his scientific career. “Jean-Louis called about plans for a new expedition. At first he wanted to build an oceanographic schooner, but I had to tell him that they are both complex and expensive. Next he started thinking about an autonomous drifting research station that could withstand the planet’s roughest seas. It was then that we started to think really hard.” After discarding the idea of a large floating platform, Laurent Mermier recalled the Floating Instrument Platform, or FLIP, that the US Office of Naval Research had operated in the 1950s. Like a spar buoy, FLIP has an observation station at one end, a long spar, and ballast at the other end. FLIP was originally designed with the submerged spar covered in sonars to spy on enemy submarines. The vessel was later refitted for scientific missions and is still in use today. The spar concept is also applied to spar-type floating oil rigs.”

 

One of a kind

Once Jean-Louis Étienne had located FLIP’s design drawings, Laurent Mermier started work on just the sort of project he loves — a one-off. The structure is 100 metres tall. Like an iceberg, most of it is under water, with the ballast 70m below the surface. “It’s a bit like a tilting doll — also known, among other names, as a roly-poly toy. When you push it over, it automatically returns to the vertical position.” Pod stability, which is essential for scientific work, has been carefully optimised. “Knowing that there are huge waves in the Roaring Forties and Furious Fifties, we paid close attention to the Pod’s seakeeping. It’s designed to respond in counter-phase to the swell with a vertical travel amounting to one-fifth of the swell height. In a 10-m swell, the Pod will thus oscillate vertically through 2m.”

 

The design does not include any large diesel engines, but has sails to control the pod’s orientation and wind turbines, supplemented by a hydrokinetic current turbine, to charge the batteries. “One of the main aims was to make an ecologically neutral research station.” The Polar Pod is designed to accommodate five people, including two crew, and for missions lasting up to six months with one half-way resupply.

Jean-Louis Etienne is now busy raising funds. Meanwhile, several yards are ready to bid for the construction contract.

Written by Caroline Britz, translated by Steve Dyson