S# Help in a Excel spreadsheet?

jehardiman,
I have now entered the SAD# as a "natural" number (LOG(34.2)-1) in an Excel SS, and the DLR as N37 entered as a cell referenced as a formula and that seems to work. I would prefer that the SA/D could be a cell reference as a formula also, so that the spreadsheet would calculate my numerous changes on it own, but IIWII.
DLR = Cell#-N37 =(N34/2240/(N36/100)^3) The DLR is still a moving target.
SA/D =(N35/(N34/64)^0.667)=(34.2) SA/D is also a moving target.
S# =(3.972*10^(-DLR/526+0.691*(LOG(SAD)-1)^0.8)
S# =(3.972*10^(-N37/526+0.691*(LOG(34.2)-1)^0.8)

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The evolution of reason and it's relation to the S# in Naval Architecture.
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"A free floating rationale was the way most boats are created in the past." (Daniel Dennett) (born March 28, 1942) is an American philosopher who also said "Philosophers can seldom put their knowledge to practical use, but if you're a sailor, you can."

"Every boat is copied from another boat... Let’s reason as follows in the manner of Darwin. It is clear that a very badly made boat will end up at the bottom after one or two voyages, and thus never be copied... One could then say, with complete rigor, that it is the sea herself who fashions the boats, choosing those which function and destroying the others." (Émile-Auguste Chartier)

"Darwin science of evolution is a free floating rational or a bubble up methodology of design. If instead we use empirical data with peer review this is a trickle down method of design a hierarchy system of checks and balances." (Daniel Dennett)

I do believe now that this is the underlying misunderstanding about boat design that most of us newbies have. Naval Architecture is a very complex art form steeped in the methodology of science and philosophy.
Thanks,
John

Well, "Through me into shallow water."
Song written by: (Edie Brickell and Kenny Withrow)

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What is "S#"?

Found the answer: an empirical sailboat performance metric used by Eric Sponberg. Discussion of it starts with post 198 of this thread: center of flotation calculation and implications? https://www.boatdesign.net/threads/center-of-flotation-calculation-and-implications.30857/page-14

Added: Article by A. P. Brooks, originator of the S# concept. (Brooks name corrected) http://www.westlawn.edu/news/S-Number_Telltales_April_1988.pdf

 

DCockey'
Thanks for the links, maybe they will shed some light on it for me.
It's a puzzle to me, but the Sailboat Data web-site definition is. https://sailboatdata.com/
S#:
S# first appeared (that we know of) in TellTales, April 1988, “On a Scale of One to Ten” by A.P. Brooks . The equation incorporates SA/Disp (100% fore triangle) and Disp/length ratios to create a guide to probable boat performance vs. other boats of comparable size. For boats of the same length, generally the higher the S#, the lower the PHRF.
Under 2 - Slow, under powered.
2-3 - Cruiser
3-5 - Racer Cruiser
5+ - Fast/Racing

 

I found this on the Sailboat data website. https://forum.sailboatdata.com/t/s-calculations/1754
Sailboat data
S# =3.972*(10^(-[@[Dsp/LWL]]/526+(0.691*(LOG([@[SA/Dp]])-1)^0.8)))

This is a new spreadsheet formula that works with cell referenced as a formula.
S# =3.972*(10^(-V43/526+(0.691*(LOG(V37)-1)^0.8))) =3.72

 

Yup. Just no brackets and you can get away with..

 

The S# rises significantly as the boat heels over from to 10% - 20%. The water line at 0% is 17.5 +- and at 10% and 20% it is almost the full length 26.5' in turn raising the S# from 3 to S#6+. With a spinnaker the S# doubles on a run down wind @ 0%. Now how does the PHRF fleet Rules work with all of this is a mystery to me still. But gives me something to do.