Triple Number

  Corrected time is calculated as follows:

Corrected time = Elapsed time – (ToD Low, Medium or High) * Distance); or

Corrected time = ToT (Low, Medium or High) * Elapsed time

The Triple Number system provides each boat a set of three ToD or ToT coefficients (as described for Time-on-Distance and Time-on-Time) given for three wind ranges

  • Low Range (less or equal 9 knots)
  • Medium Range (between 9 & 14 knots)
  • High Range (greater or equal 14 knots)
  The Race Committee shall signal before the start the wind range to be used for scoring, but it may change this in case of significant change in the weather conditions.

Where is it shown on the certificate?




Triple Number scoring coefficients on simple scoring options on
ORC International and ORC Club certificates


How is it calculated?


The three wind velocity ranges (High, Medium, Low) are each comprised of weighted averages of several Time Allowances (s/NM) selected from the familiar seven ORC wind speeds. The “cookbook” recipe for proportions in each of the three wind ranges is given in table below. The result is a form of wind-averaging for each of the three Triple Number wind ranges:

Wind Speed 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt
Low Range 50 % 50 %          
Medium Range   8.4 % 33.3 % 33.3 % 25 %    
High Range         25 % 37.5 % 37.5 %

Single weighted average s/NM Time Allowance has been calculated as ToD for each of the three wind ranges, while ToT coefficients are then calculated by the formula ToT = 675 / ToD.


Coastal/Long Distance Triple Number scoring coefficients are calculated using time allowances for the Circular Random type of pre-selected course.


Windward/Leeward Triple Number scoring coefficients are calculated using time allowances for the Windward/leeward type of pre-selected course.


Handicap calculator

  Handicap calculatore is available for Time On Distance and Time on Time.

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