In two of the club major events we use the Portsmouth Yardstick with wind factors. It is a handicapping system for one-design sailboats of all classes. This system sponsored by US Sailing uses actual finish times of the first place boat , in the various classes all across the country to establish the HC numbers. The lower the number the faster the boat. The base boat is the Thistle, and your handicap numbers are biased on how you compare to it. The Thistle is very good light air boat. In moderate air it performs OK. In heavy air it is hard to manage. The HC number is 83.0 all across the board. If your boat HC number stayed at 99.0. You would have the exact same performance curve as the Thistle. The HC numbers consider many factors. The JSC has contributed to US Sailing for many years. The system works best with similar classes of boats on varying courses with finish times between sixty and ninety minutes. Good race committee work has a great deal of influence on the results. When racing under any handicap system the three most important things to do are;
- Be on time, read the course board, and find the marks.
- Remember you are racing the clock, not the other boats.
- Keep your air clean, avoid crowds, boats sailing in-groups are sailing slow.
The formula for corrected time (CT) is as follows: Elapsed Time (ET) in minutes and decimal seconds. (1:30:45 is 90.75) ET x 100 divided by DPN or HC equals CT. DPN is the Designated Portsmouth Number, used by the RC to get a starting order or to handicap when not using wind factors. HC is your handicap number when using wind factors. It can change when the wind changes speed. Some HC numbers go up some go down. The changes are based on the Beaufort Wind scale (BN) and are listed on the handicapping sheet. The RC is the final authority on wind speed, which determines your HC number for any given race. BN numbers are divided in to four major wind areas. They are 0-1 / 2-3 / 4 / 5-9 .We race in 1 to 5 BN 1.8 to 24.7 MPH.
With all boats sailing the same course, in wind of 11mph (BN3) and a clock time starting at 00:00 the finishes are: Sunfish 67:45, Sweet Sixteen 60:15, C-scow in 55:30. The system uses a code to identify class of boats. The Sweet Sixteen is SWSX. The Sunfish is SF and the C-Scow is C-SC
- The ET would be SN 67.75 / SWSX 60.25 / C-SC 55.50
- The HC would be SN 100.3 / SWSX 95.8 / C-SC 80.1
- The CT would be SF 67.547 / SWSX 53.100 / C-SC 69.511.
- The finishes are 1st SWSX / 2nd SF / 3rd C-SC.
The Portsmouth Yardstick uses the premise:
- That the first place boat conformed to the one design class rules and has all the equipment and crew allowed on board.
- Sailed a near perfect race for the conditions.
- That the races were sailed on several different courses during the year.
For more information go the US Sailing web site, look under Racing, then look for handicapping, and then Portsmouth. (www.ussailing.org/) I am a member of the US Sailing Portsmouth committee
If you have any questions about handicapping contact Bernie Kuse