Time on Time

Time on TimeMade Easy

a PHRF PrimerBy Robert S. PorterAssnt. Chief HandicapperPHRF – Lake Ontario


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


Process:Handicap

“standard” yachts in windward/leeward races of

varying wind strengths.



Outcome:Identify result differences

between ToT and ToD

a) Closeness of finish placesb) Distribution of finish places



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 (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


Race Course


A one nautical mile course, sailed twice around

(two upwind legs/two downwind legs)

4 miles in length

One Mile

Handicap


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 Distance

Handicap (sec/km)x Course Length (km)

subtracted fromthe Yacht’s Elapsed Time

= Corrected Time

Handicap


Time on Time

Yacht’s Elapsed Time xa Yacht’s

Time Conversion Factor (TCF)

= Corrected Time

Time Conversion Factor


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

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

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

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


Race BoatsLet us identify 3 US Sailing PHRF “Standard” Yachts to compare sailing under ToT and ToD.

J24C&C 35

J35

Select PHRF


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


Race BoatsJ24

ToD Handicap:

ToT Handicap:

566.431 401.431 + 168

TCF = 0.9947



Race BoatsC&C 35

ToD Handicap:

ToT Handicap:

566.431 401.431 + 129

TCF = 1.0679



Race BoatsJ35

ToD Handicap:

ToT Handicap:

566.431 401.431 + 72

TCF = 1.1964

Lets Go Sailing!


Race #1 6 knots of wind




Lets Go Sailing!Wind

Wind is perfectly constant during each race, and parallel to the race course



Lets Go Sailing!

J24

@ 1283.1 sec/km

@ 1231.2 sec/km

Total elapsed time 5028.6 sec(83:48.6)



Lets Go Sailing!

@ 1225.3 sec/Km

@ 1137.1 sec/km


C&C 35

@ 1034.5 sec/km

@ 1071.9 sec/km




Lets Go Sailing!

J35




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




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




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



Lets Go Sailing!

@ 893.9 sec/km

@ 679.2 sec/km


J24



Lets Go Sailing!

@ 844.3 sec/km

@ 622.6 sec/km


C&C 35



Lets Go Sailing!

J35

@ 720.9 sec/km

@ 594.7 sec/km





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




How did we do? ToT


C&C 35 2933.8 x 1.0679 3133.0

J35 2631.2 x 1.1964 3148.0





2nd C&C 35 74.63rd J24 131.0

ToT 1st J24 0.0 2nd C&C 35 3.53rd J35 18.5



Lets Go Sailing!

J24

@ 828.5 sec/km

@ 524.6 sec/km




Lets Go Sailing!

@ 773.8 sec/km

@ 484.9 sec/km


C&C 35



Lets Go Sailing!

J35

@ 663.5 sec/km

@ 456.1 sec/km





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




How did we do? ToT


C&C 35 2517.4 x 1.0679 2688.3

J35 2239.2 x 1.1964 2679.0





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



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




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




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




How did we do?

Lets take a look at how racing at 90% of VMG will impact race results.

@ 90% vmg




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




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




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




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 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

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



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.



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.


Questions?


Thank You!

By Robert S. Porter

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Time on Time