The Straits of Gibraltar are an unavoidable difficulty which can throw up some freak weather conditions.

There is always a lot of wind off the rock but it can veer rapidly 180 degrees from straight up your back to right in your face, with permanent gusts of between 30 and 40 knots.

It can brusquely accelerate and reach 50 knots near the rock. Yet 20 miles before or after, the wind can be virtually non-existent. This passage is not really strategic but crews will have to anticipate sudden wind variations so as not to lose any time.

Fortunately the conditions persist only for a few dozen miles and all the skippers will have have already made the passage in both directions in previous Round Europe Yacht Race challenges.

>> More Challenge Mondial information from the BBC Weather Centre