Antarctic, D’Urville Sea
Lat/Lon: 64º11’01″S, 135º33’56″E
We have been sailing for one month, traveling nearly 5,000 nautical miles since leaving Cape Town. For over two weeks, we have been crossing waters surrounding Earth’s coldest continent. Our journey across the seas of the East Antarctica brought encounters with a great number of icebergs and rather weak winds, despite a few days of continuous storm.
When preparing for our circumnavigation of the Antarctica, I had analysed the January through mid-March wind circulation history of the past few years for the entire route. Considerable wind variability proved to be the only regularity, in terms of velocity and direction alike. The past years have been substantially diverse as to the number of days with weak and strong winds (below 10 and over 25 knots, respectively). Weak winds are an issue for 15-30% of the time spent in the Antarctic; one can count on strong winds for 15-25% of the journey.
In the course of our voyage, since entering the Antarctic waters, we have recorded a mere 20% of days with daily runs over 170 nautical miles, whereas the share of weak-wind days has reached a staggering 35%. In recognition of our lack of progress in the wake of a struggle with a heavy storm when entering the Davis Sea it transpires that we have been recording low daily runs nearly every other day. Hence the question: are we facing an exceptionally unfavorable year for sailing in the Antarctic? We have been traveling for nearly one-third of the time planned for the voyage, and have covered just over one-fifth of the route around Antarctica. It is far too early to answer the question. Weather forecasts for the coming days are much better, and I am hoping to improve our daily run performance.
Sailing in weak winds is very demanding. To maintain the correct speed – and thus our maneuverability – we have to constantly trim the sails. We need maneuvering velocity to avoid ice obstacles we are surrounded by in abundance. We have already left the Antarctic Cooperation Sea, Davis Sea, and Mawson Sea behind. We are now crossing the D’Urville Sea. We will remember the entire area between the 80th and 135th eastern meridian as iceberg land. We encountered the greatest number of bergs when sailing around pack ice emerging from the Shackleton Ice Shelf. We have our own deck name for it – Ice City. We had spotted more than one hundred floating icebergs within range of sight in the Ice City, whereas their usual number has never exceeded forty.
Sailing between icebergs resembles traveling a reservoir chock-full of islands, fundamental differences being their absence on any map and their ability to travel regardless of the wind, as they are propelled by underwater marine currents. Such sailing requires incessant attention.
In the course of our voyage, we have been encountering bergs in different stages of disintegration. Huge ice table islands are a frequent sight. Relatively young, in all probability they were severed from the ice shelf this season. Floating on the waves majestically, their sheer size and soaring cliffs demand respect. The many visible caves have been eroded by waves crashing against their walls. Such islands are often accompanied by streaks of fine ice and recently detached large growlers. The process of violent ice uncoupling is called calving. When an ice wall calves, the entire iceberg’s centre of gravity may shift, causing it to roll. The newly revealed form protruding from the water is frequently eerily shaped. Watching such phenomena from relatively trivial distance leaves us in awe and respect for the forces of nature.
We are now sailing east, along the 64th parallel. The ice sheet lies a mere few miles south. The Somov Sea awaits ahead, allowing our journey further south. The Somov Sea is home to Balleny Islands. We hope to see land for the first time since leaving Cape Town, more than one month ago…
Keep your fingers crossed,
– Mariusz Koper