Those who followed the early stages of this year’s Rolex Fastnet Race will surely have been intrigued by how well the front runners in the Class 40 fleet appeared to handle the brutal wind against tide conditions that caused problems for a lot of other boats. Conventional wisdom has it that a slim, narrow hull is ideal for sailing upwind in a blow. Yet the recent Class 40s carry their immense beam well forward of the mast, with a bow that’s closer to a square shape than a conventional point.
However, when heeled these boats present a relatively narrow immersed section that doesn’t slam into a head sea with the intensity that the flat saucer-like hull might suggest. At the same time they have enormous righting moment, which gives power to punch over big waves and reduces the total time spent sailing to windward. This stability is also an important factor in the boats’ behaviour in strong gusts: an increase of wind that would have
