Past B-15J

The latest on Banque Populaire, while router Marcel van Triest tells us how he deals with ice hazards

Chart above courtesy of Expedition/Tasman Bay Navigation Systems and PredictWind

Much of yesterday the Banque Populaire crew spent in survival mode in 40+ knot winds as the front passed them, attempting to keep the boat speed down to 30 knots to preserve the structure of their 40m long trimaran. Over the last 12 hours the 40m maxi-tri has been easing her course north, away from the strongest winds generated by the depression, but with the more serious aim of avoiding ice.

Overnight Banque Populaire passed iceberg B-15J. Still around 12 miles long by 5 wide, B-15J is the largest remnant of iceberg B15 which when it calved from the Ross Ice Shelf in 2000 was 4,150 square miles in size (or half the size of Wales, 28 times the size of the Isle of Wight). In November this year, B-15J was located at 55.3°S 159.4°W, but has since drifted northeast at around 0.5 knots to 53°10S 154.40E.

According to Banque Populaire's shore-based router Marcel van Triest, the crew have had B-15J as a waypoint on their round the world course pretty much since they left.

While B15-J remains the scale of a reasonably-sized island, a large chunk of it has broken off recently. However van Triest says that the big isolated bergs don't represent a great hazard as they are easy to spot. Of considerably more concern is that to the east of this there remains a more dangerous field of smaller bergs and growlers. "What we are trying to avoid are the clustered and bigger concentrations," he says.

Understandably van Triest groans that his work in recent days with Banque Populaire has been less traditional weather routing and more negotiating an obstacle course, as he attempts to place them where they will avoid ice. Currently this is extremely frustrating since to achieve this will require sending the boat north where a ridge will cross over her. He adds that until recently his routing the maxi-tri to Cape Horn was showing a variation of some four days in terms of her arrival time...

Threading the world's fastest offshore race boat through ice is no mean feat as it has to take into account water temperature, current, wind strength and direction, the drift of the bergs and in particular time of day, sea state and visibility.

Working with on board navigator Juan Vila, Van Triest is going to be sending the maxi-tri down a corridor through this ice zone over the next 48 hours. The boat's next waypoint is at 51°S 145°W and sometime after that she will turn on to an ESE course down a 2° wide corridor through the ice zone before she can turn to starboard and head back south to begin her approach to Cape Horn.

Fortunately to assist him, Van Triest is working with a company in Canada that for a fee will point their satellite towards the Southern Ocean and from the pictures that come back the position of bergs can be extrapolated with some accuracy. It is for this reason, says van Triest, that for example they felt able to sail south of Kerguelen Islands (back in the Indian Ocean) with some confidence.

See the latest blogs from crewman Brian Thompson here