[Jeff_H]

I think that a better way to look at this is by displacement. The traditional rule of thumb was that a proper cruising boat needed a displacement of three to five long tons of displacement per person. In recent years, better hardware has permitted that ideal weight to creep up a little and the current trends in loading boats up with modern equipment and all of the comforts of home, has pushed that range up to closer to 11,000 to 15,000 lbs. of displacement per person.

Historically, a cruising boat with a 3 to 5 ton displacement would have been 28 to 32 or so feet in length. When you look back at earlier distance cruisers, they tended to use boats that were comparatively short when compared to the norm today. This shorter length resulted in a high length to displacement ratio (L/D) typically in a 250 to 350 range. These old style cruisers were typically pretty shallow, and carried a larger percent of their weight in their hull and rig resulting in a lower ballast to weight ratio and consequently less stability. As a result they also tended to have less sail area and lower aspect ratio rigs in proportion to their displacement with a SA/D ratio in the range of 14 to 16 or so.

But using modern materials and a better understanding of marine structures and hydrodynamics a 3 to 5 ton distance cruising boat can safely have an L/D of 160 or so and still have a higher ratio of ballast to displacement than its predicessors. This lighter L/D typically means a more easily driven hull and the greater ratio of ballast to displacement placed lower in the water can result in the ability to carry more sail. On more modern designs a SA/D ratios above 20 are not all that unusual. That combination means that the boat has enough sail area to sail at a reasonable speed in light air and an sufficiently easily driven hull to get by with less sail area in a blow.

Jeff