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FOMA PHRF RATINGS

as of 2-1-99

How the PHRF Ratings are calculated and applied

FIRST, eight standard assumptions are made;

1. the spinnaker pole length is equal to "J"
2. the spinnaker maximum width is 100% of "J"
3. the spinnaker maximum length is equal to .95 of the jibstay length.
4. the genoa LP is between 150% and 155% of "J"
5. the boat is in racing condition
6. the boat has a folding or feathering propeller, a two bladed solid propeller in aperture, or a retractable outboard motor.
7. the hull and appendages are unmodified, and
8. full length battens are usually allowed without penalty.

9. the base PHRF ratings are derived from nationally published PHRF ratings

SECOND, the following variances from standard are applied;

Item Details PHRF Adjustment

square-top mainsail -6

non-standard size mainsail _% change in area +/-3 per5%

non-standard size job _% change in area +/-3 per5%

non-standard size genoa _% change in area +/-3 per5%

non-standard size spinnaker _% change in area +/-3 per5%

screacher +/-12

non-standard size screacher _% increase in area +/-3 per5%

bowsprit -3

longer than standard bowsprit -3 per 2 ft increase

rotating mast -3

carbon fiber mast -3

rudder modification -3

hull extension (swim step) -3

jib & main only (JAM rating) no screacher/spinnaker +9

screacher but no spinnaker +3

THIRD; a time on time correction factor is calculated.

A time correction factor (TCF) that that is used for Triangular Courses:

TCF = 650/(550 + PHRF #)

For port-to-port racing, a denominator of 450 + PHRF # is used:

650/(450 + PHRF #)

FINALLY, The actual Elapsed Time is multiplied by the TCF to yield Corrected Time:

CT = ET x TCF

FOMA believes that time on time generally works better than time on distance under most circumstances.