“I think this edition of the race has been a major breakthrough,” said Dee Caffari, the British skipper of Turn the Tide on Plastic, “and the fact that every boat is now mixed speaks volumes, and we would never have got that without the rule change. But for me the genuine test of whether this has worked is if in the next edition there are girls actually on crews and if girls are naturally selected, and I am skeptical that would happen if we don’t still have a rule.”

Another existing rule obliges teams to use at least two sailors under age 30 on board, so some team leaders are concerned that with smaller crews, the race could lose its identity if the emphasis is not on hiring the best crew, irrespective of age or gender.

“Let’s say there’s only five people,” said Mark Towill, team director of Vestas 11th Hour Racing. “Is there an under 30? Is there a female? Is there a national component to it from your sponsor? If so, all of the sudden, what are we doing? Is it a fully crewed, professional, top-of-the-line race? Or is it something else?”

Caffari, 45, is an adventurer as much as a sailor. She is the first woman to have sailed solo around the world in both directions — with and against the prevailing winds and currents. And yet as the sole female captain in this race, she has questioned herself at times and not only because her youthful crew, made up of five men and five women, has struggled to match the pace of the other teams.