Post on 11-Jan-2016
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Time on TimeMade Easy
a PHRF PrimerBy Robert S. PorterAssnt. Chief HandicapperPHRF – Lake Ontario
Time on TimeMade Easy
So easy, even
Jim Teeters
can understand it.
Goal: To compare and contrast: Time on Time (ToT) and Time on Distance (ToD)
Handicapping
Time on Time – a PHRF Primer
Time on TimeMade Easy
Process:Handicap
“standard” yachts in windward/leeward races of
varying wind strengths.
Time on Time – a PHRF Primer
Time on TimeMade Easy
Outcome:Identify result differences
between ToT and ToD
a) Closeness of finish placesb) Distribution of finish places
Time on Time – a PHRF Primer
Time on TimeMade Easy
Time on Distance (ToD)
Time on Distance HandicappingArrives at a yacht’s corrected elapsed time by:
Multiplying a yacht’s handicap in seconds per mile by the course length
Then subtracting (or adding) the result from (or to) it’s elapsed time.
It is independent of :a yacht’s elapsed time.
Time on Time – a PHRF Primer
Time on Time (ToT)
Time on Time Handicapping Arrives at a yacht’s corrected elapsed time by:
Multiplying a yacht’s elapsed time (in seconds) around a course
By a time correction factor (handicap multiplier).
It is independent of :race course length.
12
39
6
Time on Time – a PHRF Primer
Race Course
Time on Time – a PHRF Primer
A one nautical mile course, sailed twice around
(two upwind legs/two downwind legs)
4 miles in length
One Mile
Handicap
Time on Time – a PHRF Primer
Yacht’s Elapsed Time =
Upwind VMG x 2 km+
Downwind VMG x 2 km(in seconds)
VMGs provided by US Sailing – Offshore Office
Handicap
Time on Time – a PHRF Primer
Time on Distance
Handicap (sec/km)x Course Length (km)
subtracted fromthe Yacht’s Elapsed Time
= Corrected Time
Handicap
Time on Time – a PHRF Primer
Time on Time
Yacht’s Elapsed Time xa Yacht’s
Time Conversion Factor (TCF)
= Corrected Time
Time Conversion Factor
Time on Time – a PHRF Primer
Time on Time
TCF = 650.000 650.000 + PHRF
Mean (0) boat’s sec/mi
0 boat’s sec/mi PHRF sec/mi
As recommended by US PHRF
[A yacht with a “0” handicap is expected to complete a one mile course in 650 seconds]
PHRF - LO
Time on Time – a PHRF Primer
Time on Time
PHRF Lake Ontario has been using ToT scoring for the past 25 years.
Currently, PHRF-LO has 1600 yachts racing with current certificates
Each year PHRF-LO does a statistical analysis of 90% of all races (club & regattas) – mostly windward/leeward
www.PHRF-LO.org
Time on Time – a PHRF Primer
Time on Time
TCF = 566.431 401.431 + PHRF
The PHRF-LO experience with using Time on Time has developed the
following ToT formula.
PHRF - LO
Time on Time – a PHRF Primer
Time on Time
TCF = 566.431 401.431 + PHRF
Mean boat’s (165) sec/km
0 boat’s sec/km PHRF sec/km
As used by PHRF-LO
[The median yacht in PHRF-LO is handicapped at 165 and the “0” yacht has been proven to complete a 1 km course in ~401 seconds]
PHRF - LO
Time on Time – a PHRF Primer
Race BoatsLet us identify 3 US Sailing PHRF “Standard” Yachts to compare sailing under ToT and ToD.
J24C&C 35
J35
Select PHRF
Time on Time – a PHRF Primer
Race BoatsJ35Boat Preparation
Crew AbilitySkipper Ability
Sails
It is defined that all yachts are equally prepared
and sailed.
They sail at 100% of VMG
168 sec/km x 4 miles = -672 sec
Time on Time – a PHRF Primer
Race BoatsJ24
ToD Handicap:
ToT Handicap:
566.431 401.431 + 168
TCF = 0.9947
129 sec/km x 4 miles = -516 sec
Time on Time – a PHRF Primer
Race BoatsC&C 35
ToD Handicap:
ToT Handicap:
566.431 401.431 + 129
TCF = 1.0679
72 sec/km x 4 miles = -228 sec
Time on Time – a PHRF Primer
Race BoatsJ35
ToD Handicap:
ToT Handicap:
566.431 401.431 + 72
TCF = 1.1964
Lets Go Sailing!
Time on Time – a PHRF Primer
Race #1 6 knots of wind
Time on Time – a PHRF Primer
Race #2 12 knots of wind
Race #3 20 knots of wind
Lets Go Sailing!Wind
Wind is perfectly constant during each race, and parallel to the race course
Race #1 6 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!
J24
@ 1283.1 sec/km
@ 1231.2 sec/km
Total elapsed time 5028.6 sec(83:48.6)
Race #1 6 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!
@ 1225.3 sec/Km
@ 1137.1 sec/km
Total elapsed time 4724.8 sec(78:88.8)
C&C 35
@ 1034.5 sec/km
@ 1071.9 sec/km
Total elapsed time 4212.8 sec(70:12.8)
Race #1 6 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!
J35
Race #1 6 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do?
Boat ET Hdp CET J24 5028.6 -672 4356.6
C&C 35 4724.4 -516 4208.8
J35 4212.8 -288 3924.8
ToD
Race #1 6 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do?
Boat ET Multiplier CET J24 5028.6 x 0.9947 5001.9
C&C 35 4724.8 x 1.0679 5045.6
J35 4212.8 x 1.1964 5040.2
ToT
Race #1 6 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do?ToD 1st J35 0.0
2nd C&C 35 284.03rd J24 431.6
ToT 1st J24 0.02nd J35 38.33rd C&C 35 43.7
Race #2 12 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!
@ 893.9 sec/km
@ 679.2 sec/km
Total elapsed time 3146.2 sec(52:26.2)
J24
Race #2 12 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!
@ 844.3 sec/km
@ 622.6 sec/km
Total elapsed time 2933.8 sec(48:53.8)
C&C 35
Race #2 12 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!
J35
@ 720.9 sec/km
@ 594.7 sec/km
Total elapsed time 2631.2 sec(43:51.2)
Race #2 12 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do? ToD
Boat ET Hdp CET J24 3146.2 -672 2474.2
C&C 35 2933.8 -516 2417.8
J35 2631.2 -288 2343.2
Race #2 12 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do? ToT
Boat ET Multiplier CET J24 3146.2 x 0.9947 3129.5
C&C 35 2933.8 x 1.0679 3133.0
J35 2631.2 x 1.1964 3148.0
Race #2 12 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do?ToD 1st J35 0.0
2nd C&C 35 74.63rd J24 131.0
ToT 1st J24 0.0 2nd C&C 35 3.53rd J35 18.5
Race #3 20 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!
J24
@ 828.5 sec/km
@ 524.6 sec/km
Total elapsed time 2706.2 sec(45:06.2)
Race #2 20 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!
@ 773.8 sec/km
@ 484.9 sec/km
Total elapsed time 2517.4 sec(41:57.4)
C&C 35
Race #3 20 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!
J35
@ 663.5 sec/km
@ 456.1 sec/km
Total elapsed time 2239.2 sec(37:19.2)
Race #3 20 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do? ToD
Boat ET Hdp CET J24 2706.2 -672 2034.2
C&C 35 2517.4 -516 2201.4
J35 2239.2 -288 1951.2
Race #3 20 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do? ToT
Boat ET Multiplier CET J24 2706.2 x 0.9947 2691.8
C&C 35 2517.4 x 1.0679 2688.3
J35 2239.2 x 1.1964 2679.0
Race #3 20 knots of wind
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do?ToD 1st J35 0.0
2nd J24 83.03rd C&C 35 250.2
ToT 1st J35 0.02nd C&C 35 9.33rd J24 12.8
Compilation of Results
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do?Yacht 6kts 12kts 20kts Ave.
ToD J24 3rd 3rd 2nd 2.67C&C 35 2nd 2nd 3rd 2.33J35 1st 1st 1st 1.00
ToT J24 1st 1st 3rd 1.67C&C 35 3rd 2nd 2nd 2.67J35 2nd 3rd 1st 2.00
Compilation of Results
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do?Place 6kts 12kts 20kts Ave.
ToD 1st 0 0 0 0.002nd 284.0 74.6 83.0 147.23rd 431.6 131.0 250.3 271.9
ToT 1st 0 0 0 0.002nd 38.3 3.5 9.3 17.03rd 43.7 18.5 12.8 25.0
Compilation of Results
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do? Sec/km
Place 6kts 12kts 20kts Ave.ToD 1st 0 0 0 0.00
2nd 71.0 74.6 18.6 36.83rd 107.9 32.7 62.6 68.0
ToT 1st 0 0 0 0.002nd 9.6 0.9 2.3 4.33rd 10.9 4.6 3.2 6.2
Compilation of Results
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do?
Lets take a look at how racing at 90% of VMG will impact race results.
@ 90% vmg
Compilation of Results
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do? @ 90% vmg
Yacht 6kts 12kts 20kts Ave.ToD J24 3rd 3rd 3rd 3.00
C&C 35 2nd 2nd 2nd 2.00J35 1st 1st 1st 1.00
ToT J24 1st 1st 3rd 1.67C&C 35 3rd 2nd 2nd 2.67J35 2nd 3rd 1st 2.00
Compilation of Results
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do? @ 90% vmg
Place 6kts 12kts 20kts Ave.ToD 1st 0 0 0 0.00
2nd 85.2 27.0 20.5 44.43rd 130.6 46.9 33.7 70.4
ToT 1st 0 0 0 0.002nd 10.6 1.0 2.6 4.73rd 12.1 5.1 3.6 6.9
Compilation of Results
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do? Sec/kmPlace 100% vmg 90% vmg
ToD 1st 0.00 0.002nd 36.8 44.43rd 68.0 70.4
ToT 1st 0.00 0.002nd 4.2 4.73rd 6.2 6.9
Compilation of Results
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
How did we do? ToT – US S
Race 6kts 12kts 20kts Ave.ToT 1st 0 0 0 0.00PHRF-LO 2nd 38.3 3.5 9.3 17.0
3rd 43.7 18.5 12.8 25.0
ToT 1st 0 0 0 0.00US Sailing2nd 42.6 4.0 10.5 19.0
3rd 48.8 20.5 14.2 27.8
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
Time on Distance
must know exact course length error in course length = error in time adjustment. (1% error(60 ft) ~ 6-12 s/m)
Racers know handicap at start of race Correction does not increase during “no-wind” conditions.
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
Time on Time
Racers do not know handicap at start of race
Correction increases during “no-wind” conditions.
Need not know course length Error in course length does not = handicap error
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
Results Suggest:Time on Time scoring reduces the difference among yachts scored by 90% over Time on Distance.
Time on Time scoring spreads finishes more evenly amongst the fleet when compared to Time on Distance.
Time on Time – a PHRF Primer
Lets Go Sailing!Wind
Results Suggest:Results remain consistent whether racing at 100% or 90% of vmg.
US Sailing and PHRF – LO Time on Time conversion factors score consistently against each other.
Time on TimeMade Easy
Questions?
Time on TimeMade Easy
Thank You!
By Robert S. Porter