By Adam Bloodworth Make new friends on a yacht so handsome you imagine she’ll sail up into the air: Adam Bloodworth *goes aboard Le Ponant for City A.M. – The Magazine* A kilometre off the coast of Cassis, and I’m doing backstroke. In my peripheral vision I catch a black speed boat reverse each time I move my arms. In a crisply ironed shirt, the crew member adapts the vessel’s position to match my strokes. I test the formula: I swim forwards a bit, and the speed boat lines up with me again, always remaining exactly 20 metres away. Framing the French Riviera on the skyline is Le Ponant, the boa…