Skippers in the Global Challenge are still pursuing widely different tactics – the latest positions show the fleet spread across a front of nearly 350 miles. For now, the advantage seems to be swinging away from the current leaders in the western group, headed by Matt Riddell in Samsung, to those in the east, but as the yachts gradually converge in the next few days, we’re about to see who has it right.

Some software troubles with email and weather data have been hampering two of the yachts, but these have now been fixed on Vaio and a solution for Me To You is imminent, says Challenge Business. The only other known problem affecting performance has been a broken pole on BG Spirit (each yacht carries two poles). Ingeniously, the crew repaired it by using pipecot poles as splints.

In the next few days, the yachts will pass the Cape Verde Islands. Some may be tempted to sail between the islands, as they did at the Canaries. The wind acceleration zones here are not so pronounced, but the wind shadows are – the islands spin off turbulence that extends a very long way to the south and south-west, a surprisingly extensive effect that is plainly visible in the NASA satellite image shown.

Regardless of where yachts lie at this stage of the leg, though, the real test lies at the next stage. Leg positions are most likely to be affected by how quickly teams punch through the ITCZ, or Doldrums, which separates the two belts of tradewinds. It’s a trade-off, but the easterly boats will already be trying to use their current downwind angle to squeeze back to the west, where the convergence zone is generally narrower.

Sometime in the next week or ten days the steady north-east tradewinds should give way to the hot, humid and frustrating conditions of the Doldrums. Besides calms, there will be unpredictable thunderstorms, squalls and torrential downpours, sometimes with a choppy sea state as squalls pile up waves from different directions.

Radar will help spot these squalls and occasionally make it possible to ‘join the dots’, but inevitably the yachts are going to meet fluky conditions. Numerous wind shifts and changes in wind speed here make it hard to be sure that you have the right sail up and are heading in the right direction. Each sail change takes time, and it will be exasperating for crews to make a difficult change only to find a few minutes later that they need to change back.

Yet however frustrating these conditions may be, the Doldrums is an area where many miles can be won or lost, all of which are going to be very important down the line.

On a lighter note, a crewmember on SAIC reported today that, among other items discovered on board, including a skateboard and a box of 200 sticks of rock, was a claw hammer welded to the hull since construction.

Good story, laughs Alistair Hackett, logistics director of Challenge Business, but “I don’t believe it. We’ve done one race already with these boats and spent the whole winter crawling over them ourselves. Until someone officially shows me in Buenos Aires, it’s officially not true!”