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PHRF Time on Time Conversions

posted Sep 11, 2016, 12:03 PM by Thomas Hunter   [ updated Sep 11, 2016, 2:08 PM ]
After attempting to wing a conversion during the fall regatta and failing to anticipate our placings, I decided some research was needed.  Here is the culmination of my research.  The table below shows all the 2016 boats registered with PNW PHRF for Milltown with their assigned rating. I then calculated the time conversion factor that the Time on Time handicap formula uses for each boat (Based on the current Racesail program. (For more detail, go to www.racesail.org and look at the manual - PHRF with time on time will have a correction factor computed from the formula: A/(B + PHRF) where the constants, A and B can be chosen in the Preferences section. Typical values are 700 for A and 550 for B.)  In the last two columns are applied corrections if you raced for 1 hour and time correction it takes to get a one hour corrected time. Espresso, with a 150 rating has a TCF=1 so our finish time gets no correction. If there is a 1 hour race, for us to beat say BOB, we would need to finish within 46 seconds.  For us to beat Exit, we would need to finish more than 3 minutes and 21 seconds.  And if Ardea comes out of nowhere and finishes within 8 minutes and 14 seconds, we are hosed!  Hopefully this will help everyone one with their stop watches at the end of a race! 

Quick Postscript.  I was double checking my work and if you do pull this out into Excel and attempt to reproduce race results, the rounding for the time correction factor may come into play.  So use the data with some caution.  You can always recalculate the time correction factor your self by plugging in the formula shown above.

Postscript 2: I updated the table as I realized that just doing the difference in time assuming you sailed for an hour was incorrect.  (I had my troubles with algebra!) .  The 1 hour race correction column is the time difference it would take to get a corrected time to 1 hour.  I updated the text based on this table.  Green is a subtraction (Good for us!) from 1 hr and red is addition to 1 hour.

If you are interested, I have this posted in Google Docs and linked in the Racing resources page.

SailNumYachtNameOwnersClassRatingRatingCodeTime Correction Factor1 Hour RaceCorrection needed for 1 hour corrected time
79117FAMILY AFFAIRTHOMAS BUUSBENE45F5-36655351.1363641:08:110:07:12
64996HAPPY SEALDENNIS B MARSDENJBOA32-112348651.0401191:02:240:02:19
207SORCERERSHAUN WURZNERERIC38-212925451.0309281:01:510:01:48
59746BOBJOE GECKJBOA30-114155551.0130251:00:470:00:46
79160ENDLESSCHIP HANDEWITHHUMC37.5L14135441.0130251:00:470:00:46
45MISTRALDEAN SEVONCAL39-314735421.0043041:00:150:00:15
74244TATSAODURELL HERMANGOMX30-11475455R1.0043041:00:150:00:15
18363ESPRESSOBRAD ABELSEXPR27-1150556M1.0000001:00:000:00:00
7090COOKIE MONSTERTHOMAS J HUMESANZ27-1156556M0.9915010:59:290:00:31
79080IZARRAANDREW HARVILLABENE411-21565335R0.9915010:59:290:00:31
75MEI LIGRANT L ALBERTBENE32S5-217155550.9708740:58:150:01:48
356TSUBAKI MARUBILL/ KARINE DAVISCATA32017133440.9708740:58:150:01:48
79154SANS SOUCISTEVEN CARLSONCAL31-117745450.9628610:57:460:02:19
57573FREEFLYTEJONATHAN M CRUSEFREY39-118035650.9589040:57:320:02:34
177SWEET SUE IIDAVID MOTTERCATA36-11893C450.9472260:56:500:03:21
15160EXITJIM OOSTERHOFSTWO7.918955550.9472260:56:500:03:21
60487LUNADAVE BUETOWPEAR30-118925350.9472260:56:500:03:21
1266THUNDERBABYDUANE EMNOTTTHUN26-ODR195ODR0.9395970:56:230:03:51
39986BITTER SWEETDAVID HANDEWITHMILL29-119854450.9358290:56:090:04:07
5008SCOTCH & SODAKENNETH J MCKENZIECATA30-120146450.9320910:55:560:04:22
0WINDRIFTMARK FEIJONEWP28-221033550.9210530:55:160:05:09
2371MANUTEARICK HUNTERCATA30-121035540.9210530:55:160:05:09
79103DULCINEAJEFF SCHROEHERCAL28-22135B450.9174310:55:030:05:24
69379BINGOWALTER D NORTHFIELDPERR24-1243155MR0.8827240:52:580:07:58
70PAPAROPATRICK  GREERERIC27-1246345M0.8793970:52:460:08:14
670ARDEAJAMES STEINERIC25+24645340.8793970:52:460:08:14
0LADY EILEENBARRETT CRABTREEBABA30-124923450.8760950:52:340:08:29
0CIELO SIN FINDALE BEECHBABA30-1261S3430.8631320:51:470:09:31

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