**USE
of PORTSMOUTH NUMBERS(D-PN) or WIND DEPENDENT HANDICAPS(Beaufort Range)**

(WEBMASTER
NOTE: This page is built on Guidelines issued by the USYRU Portsmouth Yardstick
System. Examples are based on National
One-Design racing, and intended to make “mixed” fleet racing easier for NODRA
and NOD boat owners.)

__DECISIONS
BEFORE RACING BEGINS__

A. Handicapping:

1) Decide on handicapping method/systems to be
used.

a)
D—PN “only” for handicapping.

b)
Wind Velocity Handicaps(Beaufort Range)”only” (determining the average wind
velocity required).

c)
D—PN or Wind Velocity Handicaps modified for allowances.

2) Determine handicaps for all non-listed classes
before racing begins.

3) Grouping boats into fleets by handicaps is
optional.

B. Scoring:

Decide
on method for scoring.

C. Time Limit:

Consider
time limits. Changing weather conditions during a race will upset the
handicapping system. A one hour race for the bulk of the fleet is recommended.

D. Course:

Triangular
courses of equal beating, reaching, and running legs are recommended for
handicap races.

__RACING__

A. Record start and finish
times for each boat in the handicap fleet(s) and for first boat to finish in
one—design or level racing fleet(s).

B. Record wind velocities
at the start, middle and finish of each race.

C. Determine average wind velocity (this is the
sole responsibility of the Race Committee, whose decision is final).

__ __

__CALCULATION__

A. Determine elapsed
times(ET) for each boat of the handicap fleet(s) and for first boat to finish
in one—design or level racing fleet(s).

B. Determine average wind
velocity for each race. Determine Beaufort Number range and appropriate
handicap “if” wind velocity handicaps are being used.

C. Calculate
the Corrected Times(CT) from Elapsed Times (ET) and handicaps (HC) using the
formula:

ET (using decimals
for seconds)

CT = ---- x 100

HC

D. Score
race and determine places based on shortest corrected time (CT).

__EXAMPLE__

1) A National One-Design(D-PN 96.3), a Thistle(D-PN
83.0), and a Laser(D-PN 91.3) have decided to race using the D-PN handicap
method. The race committee is new and
does not believe it can apply the “HC Beaufort Range” properly. All 3 boats start at 1:00:00 PM and sail
“once and a leg” on a triangular course set to winward. The Laser crosses the finish line at
1:45:56, the National One-Design(NOD) finishes at 1:46:01, and the Thistle
finishes at 1:48:00. Which boat has
“won” the race ?

2) Let’s determine the Elapsed Times (ET)

BOAT Times HH:MM:SS ET
ET in DECIMALS

------------------- ----------------- ------- ---------------

National
One Design 1:46:01 – 1:00:00 = 00:46:01
= 46.02

Laser 1:45:56 – 1:00:00 =
00:45:56 = 45.93

Thistle 1:48:00 – 1:00:00 = 00:48:00 = 48.00

3) Next, determine the Corrected Times (CT)

Portsmouth Formula CT

------------------- ------------

National One Design:
(46.02/96.3)*100 = 47.78 Minutes

Laser: (45.93/91.3)*100 = 50.30
Minutes

Thistle: (48.00/83.0)*100 = 57.83 Minutes

4) Finally, rank based on CT, and the “winner” is
the National One-Design with a Corrected Time (CT) of only 47.78 minutes. The Thistle is a distant “last” with a CT of
57.83 minutes.

(Internet Note: Use your Brower’s Back button to
return to previous pages)