Join Date: Feb 2000
Location: Annapolis, Md
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Re: Bob Perry's take on Wolfenzee's dream boat
Bob, I think there are several things at play in Colin Archer's choice of hull form. As you suggest these are probably 'raters', designed around some basic form of a tonnage rule.
But Archer was also a proponent of the 'wave line principle,' which was precurser of the 'Metacentric Shelf theory'. For those reading this who are not familiar with these theories, designers were concerned that their designs changed trim with heel angle, especially as many of these boats would have long over-hangs which were likely to come assymetrically into contact with the water as the boat heeled, causing longitudinal changes in trim.
Designers wrestled with ways of analyzing and preventing this trim change. The 'wave line principle,' and 'Metacentric Shelf theory' were methods of addressing these concerns. These methodologies mostly impacted stern sections in ways that minimized contact with the water except at speed where water would be dynamically sucked up the counter.
These methods of balancing the boat with heel so it did not change trim, did improve the behavior of the boats on which they were used. But with the advent of computer analysis these methods have been shown to be relatively imnaccurate.
None the less, the shape of the end on the Colin Archer fan tail yachts would seemingly suggest that the ends were shaped from the pet theories of their day.
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Curmudgeon at Large- and rhinestone in the rough, sailing my Farr 11.6 on the Chesapeake Bay
Last edited by Jeff_H; 06-12-2013 at 01:46 PM.