LOA vs LWL, looking for a boat – Page 5 – SailNet Community

Quote:Originally Posted by davidpm View PostI just went to sailboatdata and looked up Far 395 etc and it said 25 for SA/D. The crusing boats Catalina etc were all about 17 SA/DWhat am I missing?There are a number of things that come into play. Its mostly about designing a boat as a system. So when you look at modern performance cruisers, they tend to have very tall fractional rigs with minimally overlapping headsails, bendable spars, and an inability to carry large percentage overlap genoas. These are wildly efficient sail plans in terms of drive to drag, and a configuration that can quickly be depowered rather than reefed in a building breeze. But rigs like these generate a lot of heeling moment compared to lower aspect ratio rigs and so need some mix of low drag hull forms and lots of stability. This mix makes sense because lower drag hull forms allow the rig to be smaller and produce less heeling since less drive is needed, and of course the high stability is needed to stand up to the rig over a wider range of wind speeds. In other words, what makes the high performance cruisers of the past decade or so, with their very high SA/D's work, is that they generally have a huge amount of stability relative to their drag and can therefore get by with these more efficient sail plans. Most of these designs (Think of boats like the J-122, J-130, Aerodyne 38, Cape Fear 38, Farr 395, X-4 etc.) have SA/D's in the 22 to 26 range measured with their 100% foretriangle. The actual sail area of these boats with their minimally overlapping headsails ends up roughly in the 26 to 28 range. (Even my old Farr 11.6 ends starts in the 22.5 range) In contrast, boats like the Catalinas that you mention, and most conservative coastal cruisers for that matter, are designed around carrying comparatively large overlap genoas in order to get decent mid-range sailing abilities. They are not really designed for light air performance. They generally lack the kind of high stability to low drag, that is required to carry a more efficient rig. Its just a different mindset. The reality is that most of these boats were designed with a generic owner in mind, one who is less concerned about light air performance than comfort and forgiving sailing characteristics. They are set up in ways that is consistent with not sailing at the extremes of the wind range, and without the kinds of sail shaping tools that allow a sail to be depowered quickly rather than reduced in size by reefing or furling. Jeff
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