US SAILING

Portsmouth Yardstick Formulas - Modifications 2001



MULTIHULL MODIFICATION PENALTIES AND ALLOWANCES
FOR HEADSAIL, WEIGHT and WIDTH ADJUSTMENTS

Adjustments for Open Class Racing
June 2000


2001 Modification Factors for Multihulls

(D-PN) modified = (D-PN)(MF)1(MF)2
(HC) modified = (HC)(MF)1(MF)2

All ratings for OPEN CLASS racing are based on boats being equipped with class approved sails and other class approved equipment. Each competitor shall declare ALL non class approved sails or equipment and shall comply with minimum total crew weight and number of crew. If total crew weight is under class minimum, corrector weights shall be added (or use other means of increasing total crew weight per class rules) OR use minimum crew weight penalties.
Also note the
Other penalty for deviations not identified below.

Ratings do not include spinnaker unless indicated in the Tables. Ratings do not include
carbon equipment unless indicated in the Tables or as allowed under one-design class rules.

 

US SAILING CODE

DESCRIPTION

D-PN Modification Factor (MF)
for Beaufort Range

0-1

2-3

4

5-9

TR For carrying trapezes above class allowance, per trapeze 0.981 1.000 0.988 0.981 0.963
US Class normally with small jib*, sailing uni without jib 1.026 1.036 1.030 1.026 1.026
UL Class normally with large jib*, sailing uni without jib 1.076 1.075 1.083 1.076 1.060
JS Class normally without jib, carrying small jib* 0.975 0.965 0.971 0.975 0.975
JL Class normally without jib, carrying large jib* 0.941 0.940 0.933 0.929 0.938
SP Class normally without spinnaker, carrying one 0.972 0.965 0.970 0.972 0.972
SD Class normally without spinnaker, carrying one in long distance race 0.955 0.965 0.960 0.955 0.955
GN Class normally without genoa or reacher, carrying one 0.972 0.965 0.970 0.972 0.972
SG Class normally without spinnaker or reacher, carrying spinnaker plus genoa or reacher 0.958 0.948 0.955 0.958 0.958
SN Class normally with spinnaker, not equipped with one 1.020 1.030 1.025 1.020 1.010
MN For non-class legal mainsail, of same sail area or less than class legal mainsail (formerly squaretop adjustment) 0.995 0.990 0.990 0.995 0.995
ML For non-class legal mainsail, of greater sail area* than standard main 0.980 0.969 0.975 0.980 0.985
JU For larger than standard jib 0.995 0.984 0.990 0.995 1.000
MT For taller mast than standard 0.995 0.990 0.990 0.995 0.995
BM For wider than standard beam 0.995 1.005 1.000 0.990 0.984
L1 For total crew weight less than class min. crew wt. but at least 90% of class min. crew wt. 0.991 0.990 0.991 0.996 0.999
L2 For total crew weight less than 90% of class min. crew wt. but at least 80% of class min. crew wt. 0.983 0.980 0.983 0.991 0.997
L3 For total crew weight less than 80% of class min. crew wt. but at least 70% of class min. crew wt. 0.974 0.970 0.974 0.987 0.996
L4 For total crew weight less than 70% of class min. crew wt. 0.970 0.965 0.970 0.985 0.995
H1 For total crew weight at least 110% of class min. crew wt. but less than 120% of class min. crew wt. 1.003 1.010 1.007 1.003 1.000
H2 For total crew weight at least 120% of class min. crew wt. but less than 130% of class min. crew wt. 1.006 1.020 1.013 1.006 1.000
H3 For total crew weight more than 130% of class min. crew wt. 1.010 1.030 1.020 1.010 1.000

Other


Any other deviations from standard class configurations
should be assessed a penalty of at least 0.995 or 1.005. Multiple deviations may incur multiple penalties. Penalties may be greater than 0.995 or 1.005. Please identify any such modifications and penalties assigned and include with results reported to the handicap committee and Portsmouth Numbers Committee.
 
*Definitions
     Same Sail Area: within 5% of Calcuated Approximate Sail Area
     Greater Sail Area: 5% of larger difference in Calculated Approximate Sail Area
     Small jibbed boats: boats with standard jib tacked to bridal wires and hoisted to or below mast hounds
     Large jibbed boats: boats with foils or jibs with tack attached to the deck or from cross beam and/or head attached above mast hounds

We strive to improve the validity of US SAILING's Portsmouth Numbers for Multihulls.
You and your club/fleet can help this effort by forwarding your race results annually by November 1 to
US SAILING, Portsmouth Numbers Committee, P. O. Box 1260, Portsmouth, RI 02871
or via email to
hobockd@aol.com  or via fax to Darline Hobock, 918-744-9760

Race data needed: Class of boat, elapsed times and average wind velocity.
Please indicate non-standard equipment used and/or include modification code.

To purchase the complete 2000 Portsmouth Yardstick containing all classes of boats, click here

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check out this membership for multihull sailors:

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