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In one interview I read this morning Frank Cammas is reported to have wondered if the use of different routing software was the cause of the French boats heading for the French coast (Apivia led the IMOCAs and made quite a lay line call somewhere south west of Jersey) whilst the British boats stuck to the UK coast. Might this be a Adrena vs Expedition question, or is it more likely driven (my hunch) by the short handed IMOCA crews optimising for long legs, and thinking they could get a tidal gain in the Alderney race?
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I think it is more the tide gate.
The big multis, Apivia, etc managed to get through before the tide turned.
Looking at 11th Hour’s track, they were just approaching Aldernay when the tide turned and had to tack back to the channel.
Image below is just after 11th hour tacked. The tide had just turned against them. The boats ahead got through just in time.
Any boat slower than 11th hour wouldn't have had a chance, but Skorpios could have made it work.
The TSS at Lands End was expensive for a lot of boats later on.