Once known as Hartley18
Join Date: Aug 2007
Location: Melbourne, Australia
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Re: Moment curves
I agree with Jeff's guess as to the nature of the curves. However, given the long and skinny shapes in that day I doubt very much that the heeled trim changed much at all if at all. Sail a 6 meter or even an Etchels or a Soling. There is little perceptable trim chage when heeled. I don;t know what the rest of this boat lookled like but I'm going to asume it was relatively narrow with overhangs and a short DWL. The ends are probably damn near symetrical and close to the same volume. The change in fore and aft trim would have been at the most minimal. Of course due to the bow having a point and the stern having a transom there is more volume aft so naturally the boat when heeled will go slightly bow down. But I don't see anything in those curves to tell me how much bow down.
Here she is, Bob. Built as designed: 30' LOA, 25' LWL, 9'2" Beam
..and designed specifically for a couple wanting to cruise Sydney Harbour and surrounding coastline in relative comfort.
Still that doesn't stop a guy with a lot of time on his hands from doing the calculations needed to lay out the curves. But had the curves been productive in terns of design efficiency and effectiveness I suspect we would have seen them popping up on oither designer's works.
Now, if other designers had been using the same moment curves you could do a "I'll show you mine if you show me yours" thing and that might have value. But I think in order to evaluate numbers you need benchmarks of known performance that used the exact same variables measured in the exact same way.
He might have got some things right, but I guess this was one idea that didn't take on..
Thanks all. A most interesting discussion indeed!
"Honestly, I don't know why seamen persist in getting wrecked in some of the outlandish places they do, when they can do it in a nice place like Fiji." -- John Caldwell, "Desperate Voyage"
Last edited by Classic30; 09-27-2012 at 09:03 PM.