The author of the following information is Louay from the web site ‘Bang the Corner’ www.bangthecorner.com

‘Bang the Corner’ enlisted the help of Mike Broughton to analyse the conditions that competitors in the Antarctica Cup Race will face, Mike has huge experience in the field of weather routing but his brief was to put this very technical data into layman terms so even I could understand!

INTERVIEW WITH MIKE BROUGHTON:

Q1: The Antarctica Cup is due to take place in the relatively milder Arctic Summer. However during winter the Antarctic has the strongest sustained winds on Earth, what causes such incredible wind speeds?

A1: Winds are created by temperature differentials. If you think about a normal summer sea breeze, the wind can be created by a temperature difference of just a couple of degrees centigrade, now compare the difference on a larger scale, from say the blazing heat of central Australia to the cold of Antarctica further south, with nothing in between except for the Southern Ocean.

Antarctica is topped with the largest ice cube in the world, the ice averages over one mile thick. At the South Pole the ice is actually about three miles deep and rather like an iced cake the ice thins towards the edges and breaks off into icebergs. The ice moves slowly outwards, moving between 0.3 and 1.2 miles a year.

In winter the continent doubles in size as sea ice freezes over the sea and in some places extends as far north as 54 degrees south. The northern hemisphere equivalent would be sea ice all the way from the North Pole to the River Mersey in Liverpool. If you need reminding just how big Antarctica is, just flip the globe upside down and centre your gaze on the South Pole.

Q2: Is the route around Antarctica the shortest distance to circumnavigate?

A2: No, even in summer Antarctica is still a pretty huge continent! I guess technically the shortest circumnavigation under sail would be around the Arctic in summer, via the North West Passage, round Greenland and the North East Passage – traditionally that has taken a couple of summers to achieve because of the ice.

Whereas sailing east about round Antarctica would be much faster. Charging downhill under a big kite, aided by big rollers or blast reaching with the bow out of the water is never slow when you are doing it the Southern Ocean way. I think Bob Williams and his teams of race organisers are planning on it taking about 45 days.

Q3: Icebergs in Antarctica can vary in size from small trucks to tabular icebergs, which can be over 30 square miles. What are the hidden dangers surrounding these different types of icebergs and is it true that they can roll over causing huge waves?

A3: As the icebergs break off from the edges of Antarctica and head north there is little initial melting as the sea is so cold. Once they get to the Antarctic Convergence zone, where the cold north moving water undercuts the relatively warmer sub-Antarctic water, the bergs melt and break up at a faster rate, but can still survive for several years.

The real problem for sailors though is seeing the small icebergs and growlers particularly at night or in poor visibility. On the last Volvo Ocean Race, all the fleet encountered icebergs – some closer than others. In particular New Corps’ story was particularly hair-raising and they quickly headed further north after their ice skirmish.

The furthest northern limit for icebergs is in the Atlantic sector where they get to 46 degrees south – the northern hemisphere equivalent is the latitude of La Rochelle! Large waves can be created by icebergs rolling over and interestingly the ‘calving’ of large icebergs is often related to sub ocean earthquakes and tsunamis. The area of the South Sandwich Islands is very active with volcanoes with new islands forming from under the sea with occasional fumaroles emitting poisonous gases.

The Antarctic Cup race-course sensibly takes the teams to the north of the main ice concentrations by inserting way points and gates at different stages around the Oceans.

Q4: What size seas can they expect?

A4: Just blooming huge on occasions! This is the place of the biggest waves on the planet. Having said that, people often overlook the fact that on around 1-2 days a month, you get calms in the Antarctic Ocean.

The reason for the big waves is the unrestricted fetch. Massive waves build up as they roll round the Southern Ocean largely unhindered by land with a long period to build up in the unremitting westerly quadrant winds. Where the waves hit shallow water then they can kick up really rough. The continental shelf of Cape Horn is the obvious example.

‘Rogue waves’ have only recently been accepted as a phenomenon as previously the mathematician’s used to say a wave of over 100 foot was not possible. This has now been discounted and is possible when several waves trains combine.

Recently a cruise ship encountered a huge wave near Cape Horn and the waves washed right through the bridge windows at over 100 feet above the waterline. The bridge electronics were ruined and the ship had to limp into Chile and was taken out of commission for three months. For publicity reasons the incident was kept pretty quiet.

On a smaller scale, the shallow waters of the Bass Straits have the same effect and hence the notoriety of ‘The Paddock’ as Sydney to Hobart Race sailors affectionately know the area – remember the pictures of the waves in the 1998 Hobart Race? One of the lesser-known very rough areas is where the fast flowing Agulhas current (up to four knots into wind) hits the Southern Ocean rollers at the tip of the Agulhas bank some 150 miles south of Cape Town.

Q5: Antarctica has a harsh climate. The Antarctica Cup is due to take place in the summer for obvious reasons but the average temperature in East Antarctica is -33°C for its warmest month! What sea and air temperatures will the competitors be expecting over the course?

A5: Refrigerator temperatures. Typically around 2 – 5 degrees sea temp, with air temperatures relatively mild with winds from the NW and very cold when from the SW. The wind chill of course makes it feel even colder, creating freezer temperatures.

Q6: The course for the Antarctica Cup will cover three oceans (Pacific, Atlantic, Indian). Whilst all of these oceans have been raced before is there a part of the route that has never been raced before?

A6: One interesting part is the route across the Southern Atlantic Ocean. Generally this is part of the Antarctic Ocean that is not raced across. Most races around the Southern Ocean originate in the Northern Hemisphere and turn left or right at Cape Town or Cape Horn and once back into the South Atlantic turn north again missing out the central Southern Atlantic.

Some of the most extreme weather in the Southern Ocean takes place in this area, around South Georgia and the South Sandwich Islands. Few people have ever raced a yacht past these islands.