>Bob, the question therefore is are semi-displacement hulls actually planing hulls or are they half way in between? I know most of the boats you mention are not full displacement. The term "semi-displacement" is rather misleading, and in fact a number of boat designers like Tom Fexas (sp?) use the term "semi- planing" to describe the same hull form because that's what the hull really is. A displacement hull is a hull that cannot be pushed faster than its hull speed, even with a large application of power. Excess power simply causes it to dig a deeper hole in the water although it may go a bit faster in the process. So a hull is either a displacement hull or it isn't. If it isn't, then it's either a fully planing hull or a hull that enough power can force part-way onto a full plane, hence "semi- planing." I don't know that a hull like a Grand Banks can be considered a true planing hull because the rounded forebody and full- length keel will prevent the hull from achieving a full plane unless the entire boat was an engine. But with enough power, a GB can be pushed relatively efficiently part-way toward a full plane, say 15 to 18 knots. So the GB hull is a "semi-planing" hull. I suspect the term "semi-displacement" was coined and came into favor because saying a boat is "semi-displacement" implies that it is closer to a true displacement hull with its economy, seakeeping traits, heavy-duty "workboat" characteristics, etc. It's a good image to promote in a boat. It's sort of like calling GM's gussied- up Tahoe a Hummer H2. Tahoe implies soccer mom, Hummer implies rugged, go-anywhere capabilities. Even though they use the same platform, if rugged image was an important buying criteria, which one would you buy? Calling a boat "semi-planing" implies high fuel consumption, lighter weight construction, not so good in the open ocean, etc. I think it's largely about image rather than reality. After reading stuff by Tom Fexas and others, I now use the term "semi- planing" to describe the hull on our GB or other similar boats because that's what I think they really are. A Willard, on the other hand, is a true displacement boat. ____________________ C. Marin Faure GB36-403 "La Perouse" Bellingham, Washington