Sail area to
Displacement Ratio
13-14=motor sailer
.667
14-15= slow in light air
(SA in sqft) / (DSP in cubicft)
15-16=off shore cruiser
16-17=coastal cruiser
DSP= (2400*35lbs)/ 2240 = 37.5
17-19=racer
SA=29*10/2 + 26.5*8.75/2 = 260
20-23= light racer
.667
*
23+ =ultra light racer
260 /37.5 =
23.2
Displacement to
Length Ratio
40-
50=light racing multi hull
3
60-100=ultralight mono hull
(DSP in long tons) / ( .01*LWL)
100-150=very light racing mono hull
* 150-200=light racing mono hull
DSP=2400/2240 = 1.07
200-250=light cruising auxilary
3
250-300=avg. cruising auxiliary
(.01*18.5) = .0063
300-350=moderate heavy auxiliary
350-400=heavy cruising auxiliary
1.07/.0063 = 169.8
Shaft Horse Power(SHP) required to Cruse at Hull Speed
3
3
SHP=[disp(in lbs)X (SL ratio) ] / (10.665)
.5
Hull Speed= (SLratio)(dynamic waterline)
THUS: (SLratio)=6.14/4.59=1.33
3
SHP = 2400lbs X (1.33) / 1213.06
SHP = 4.65 HP
by Micheal Tamulaites, Sailboat 1997 Buyers Guide page
164, and SAIL Magazine's Sailing Tip of the Week by Allison Peter
The PHRF rating is calculated from actual performance in the geographical area that the boat is sailing in. The North Atlantic is different from South California due to different weather conditions. Typically the PHRF rating is about 186.
PHRF LINKS
PHRF of Okanagan BC Canada Region ( modified PHRF system)
=186, PHRF Ratings for Northern California (SanFransisco) (We've been handicaped again according to the Cherokee Handicap Estimated Average Time, "C.H.E.A.T" System used by the handy cap committee.
PHRF in the Okanagan is 195 now but vary between 192 and 201 depending on sail measurement.
but In "One design racing" we arbitrarily select 195 for all the 525's.
=195, Lake Lanier Yacht Racing Assoc. ( Atlanta)
=189, North East New England
=186, PHRF Shell Regression Formula
=
176 1987) 162 (2002) , Cherokee Lake Sailing Club
