How hull shape affects comfort at sea

Julian Wolfram is a physicist, of ocean engineering at Heriot Watt in Edinburgh and a Yachtmaster Offshore who has cruised and raced for 45 years. naval architect, former professor

There are many desirable attributes sailors want in their cruising yacht. Stability is obviously a crucial factor, but there are other important factors that should be considered when judging a sailing yacht and the balance of these will depend on the type of cruising envisaged and whether there may be some club racing involved.

Comfort, or seakindliness, is high on many people’s list and a boat that bounces around or slams in a choppy sea is generally shunned by all except hardened racers who will put up with any discomfort in the pursuit of speed. However, most sailors likes to sail and a boat that can’t maintain a reasonable speed in light winds and frequently requires the use of the engine is also undesirable. When the wind picks up a bit, a yacht that responds with a good turn of speed is a delight and can make the difference between arriving in daylight and tying up in the dark after a long passage. Finally, there is course-keeping and manoeuvrability. A yacht where the helm can be left unattended for a minute or two can be a godsend to a short-handed crew, but the same crew will welcome