How To Use Portsmouth Numbers
How To Use Portsmouth Numbers
Prior To Leaving Shore:
Decide which handicapping method to use:
Wind Handicap Numbers (HC) – recommended
Basic Portsmouth Number (D-PN), or
D-PN or HC modified for allowances
For HC, you must have available a reliable method of determining the wind strength according
to the Beaufort Scale (Table I). The table gives visual clues that do not require a wind meter; however, one is recommended.
Decide if you need the optional Modification Factors
Table VI allows adjustments to an individual boat’s handicap number for non-standard sails,
non-standard configurations, etc.
Decide and post each boat’s handicap rating before racing begins.
For Best Results and Fair Handicapping:
Group boats into fleets by handicaps, if desired. Look for clusters of boats with similar D-PNs.
Consider imposing time limits. Rapidly changing weather conditions during a race can upset the handicapping system. Courses for handicap races should include fairly equal amounts of beating, reaching and running. Courses can be combinations of triangular, modified Gold Cup, Olympic,
and windward-leeward. RCs should take advantage of water available and set appropriate windward legs to get a course reasonable in length.
Equipment Needed
Device to measure wind, either a hand held wind indicator or one mounted on RC boat
Recording forms, pencils, ratings, computer or hand calculator
At least one stop watch
On The Water
1) Record starting and finishing times for each boat in handicap and level rating fleets; plus the
first boat to finish in one-design fleets, and for each windsurfer.
2) Record wind velocities at the start, during and finish of each race. Some RCs may record
more frequently in fluctuating winds. RC determines average wind velocity.
Calculation
Determine elapsed times for each boat in the handicap fleets and for first boat to finish in
one-design or level racing fleets.
If wind handicaps are being used, select column of handicaps.
Calculate corrected times (CT) from elapsed times (ET) and handicaps (HC) using the formula:
CT = ET x 100
HC
Where CT = corrected time
ET = elapsed time
HC = D-PN or wind handicap number
MF = modification factor
Score race based on shortest corrected time = 1st, etc.
REPORTING DATA