Divers from Ocean Kinetics have completed what is believed to be the first ever job that involved underwater welding in the Antarctic.
Team leader and marine projects director Michael Fox, said the trip had proved a challenge and an adventure and provided a few surprises for the five divers who were based at the Rothera Research Station for the duration of the venture.
Ocean Kinetics were contracted at short notice to repair a split in the sheet piling of a quay at the station that had been damaged by a massive ice flow. Though a mere crack at water level, the split widened to 1.4metres near the seabed, nine metres down.
The pier is essential for docking the British Antarctic Survey’s (BAS) research ships James Clark Ross and Ernest Shackleton during the summer months.
Michael said there were no special technical challenges involved in bolstering the rent in the steel piles and the job was finished two-days ahead of schedule.
The split had spilled aggregate and caused a hole in the gravel surface of the pier – gravel, because concrete won’t set properly at the temperatures found in Antarctica.
The corner of the pier is now held together by a network of tensioning chains that were welded onto the piles at each side of the split. The job entailed a “considerable amount of underwater welding and steel plating work”.
The remote location and very limited local resources meant the chosen method required a minimum of plant and could be easily adapted should the damage have worsened over the winter period.
After a four-day voyage whose final leg was a five-hour flight from Punta Arenas in southern Chile, the group disembarked from the Dash 7 transport plane to an alien terrain of flow-studded blue seas and beautiful snow-clad mountains basking in summer heat that soared to two degrees centigrade on a hot day.
Michael said the flight was one of the highlights of the trip as he spent some of the time in the cockpit with the pilots. Somewhat ominously, the plane reaches a point of no return where it no longer has enough fuel to return to Chile and must fly on to the Antarctic in the hope that the good forecast has been accurate.
Rothera, on the edge of the Antarctic Peninsula, is far nearer to South America than the South Pole and enjoys a relatively balmy climate, but temperatures still regularly hit minus two or three in February, which is summer in the Antarctic.
Michael said: “We were very lucky. We had completely still days the whole time we were out there. Sometimes it was quite warm, apart from one day it was minus 12 and quite wintry as well.”
One of the first things the men observed was that 10 minutes in the ozone-depleted sunlight was enough to leave a sunburn, so dark goggles and factor 50 sun cream became de-rigour before the team members ventured outside the huge Rothera base.
Clad in regular dry suits, the divers’ main concession to the minus one degree sea was multiple layers of thermals and 5mm neoprene gloves on top of 2mm undergloves. Although the men struggling with chains and shackles underwater were kept warm through exertion, those on welding duty were far more susceptible to the cold, and swapping around divers every two or three hours was necessary.
Once the job was complete, the pier infill was held back by a layer of membrane reinforced with a stout network of vertical and horizontal chains welded to brackets.
Rothera, the BAS logistics centre for Antarctica, is home to a population of scientists, geologists, marine biologists and support and maintenance staff.
For the full story see The Shetland Times.