The evolution of high pressure is turning Ellen's record attempt into a game of dice with very high stakes, as B&Q heads north to pass through the islands of the Azores later tonight. Every minute of MacArthur's current 3 day 10 hour lead is going to be needed to soak up the losses as she sails into the high pressure tomorrow.
Joyon doesn't have amazing mileages for the next couple of days but from Saturday he starts to wind up to blistering speeds directly towards the finish (see mileages below). The breeze will stay from the south-east today but Commanders expect lulls down to 15 knots and gusts up to 28 knots through to midnight tonight. The wind will start to diminish in the early hours of tomorrow as B&Q gets closer to the ridge of high pressure, bringing a very slow period from tomorrow afternoon through Friday. There is no avoiding the high pressure - it is too big, with the ridge axis from NE-SW stretching across MacArthur's pass - and the million dollar question is how quickly B&Q can cross the ridge to get to the other side and into more breeze. MacArthur spent 4 days trying to cross a similar high pressure ridge in the South Atlantic - in fact, she never caught it and the impact on her advantage was that it was cut to just 6 hours on Day 60 from 4 days. If and when she gets across, MacArthur faces an upwind battle to the finish line.
Ellen's lead masks the sheer hard work of keeping B&Q on track for the record as the breeze from the south-east fluctuates wildly in strength forces Ellen to find every last drop of energy to make just 'one' more more sail change. The average wind speed figures reported hourly do not tell the whole story, as Ellen struggles with the dilemma of finding the energy in the lulls to increase sail, then taking the decision to get more sail up, for the breeze to start punching upwards leaving MacArthur no choice but to decrease sail: 'I don't know whether to change up to the Solent or not [now on 2 reefs and smaller staysail], it's right on the limit in the gusts but I've only got 18 knots right now. I need to be going faster, but the sail change takes me so long now that I'm tired. And I don't want to risk breaking the Solent. The problem is that we have to make more gains now, as the weather looks terrible ahead. Current routing shows me in late Tuesday, and the trend is getting worse. Now is the only time to make gains. Sail changes taking my twice the time they were earlier in the trip
It was never going to be easy, and MacArthur knows more than anyone else that it was her choice to take on the record, and she never asks for sympathy. This is what pushes her on to drag herself one more time on to a lurching, soaking deck to make another sail change. Because now is the time to sail fast, to put more miles on the clock before the B&Q sails into the high pressure of light winds that stand between her and the finish off Ushant.
With less than 1.500 miles to go on the direct route to the finish Ellen's VMG required [Velocity Made Good to the finish] to break the record has dropped another notch to 8.4 knots. Of course, MacArthur cannot sail the direct route [approximately 30 degrees to the finish of Ushant right now] as her course is dictated by the current weather and negotiating the weather system ahead. For now, B&Q has sailed 25,749 miles at an average speed of 16.3 knots and her Distance Made Good to the finish is still out-pacing that of Francis Joyon - 412 miles to IDEC's 278 miles over the last 24 hour period.
What VMG can Ellen make in light winds? Hard to go significantly faster than the wind, whatever direction it is, so 6 knots wind, speed could be 7 knots and of course not necessary in the right direction so VMG of 3 to 7 knots say. In upwind conditions [ie tacking, zig-zagging against the wind], boat speed maximum is about 14 knots if the seastate allows it, and of course in that situation heading is unlikely to be on the direct route, so VMG could be less than 9 knots. This is why every mile of gain now might be needed, with a forecast of light winds followed by upwind conditions...