The races result at CRSC are calculated based on the Echo System following the Irish Sailing Association. The objective of the handicap system is to give every boat an equal chance in every race. Details about the rules and the calculation logic can be found below.
Echo by Irish Sailing
The handicap for each boat is a number by which the elapsed time is multiplied to give a corrected time.
For a handicap start, this number needs to be converted into several minutes. This is based on a race time for the scratch boat of 100 minutes. When the number is converted to minutes, the fractions of a minute are ignored to give start times in minutes.
The handicaps are calculated in a program called Sail 100. The method of handicap calculation used is called ECHO and was developed by the Irish Sailing Association. The principle behind the ECHO system is that it compares a boat’s corrected time with the average of all the corrected times and adjusts based on this. (Most handicap programs compare each boat only to the fastest boat) At Concord Ryde, the handicap adjustment is 20% of the difference between a boat’s corrected time and the average corrected time. A full explanation of the ECHO system can be found on the Irish Sailing Association’s website.
To convert handicap to minutes and visa versa, for a 100-minute race, the maths and tables are below. Note: If no boats are on 1.000, divide all handicaps by handicap of fastest boat. This brings all handicaps to a base of 1.000. and the fastest boat off scratch.
Calculation of handicap for following race Next Handicap = 0.8 x Handicap + 0.2 x ECHO
Let us consider the impact of this race on each boat in turn.
What does it mean in minutes?
Divide elapsed time by base time for each boat.
Divide sum of handicaps by sum of step 1
Divide step 2 by step 1 for each boat.
gives the handicap which would have resulted in a dead heat. This is the ECHO handicap. (Note: the sum of the ECHO handicaps and the sum of the handicaps is the same.)
calculate the next race handicap, multiply the existing handicap by 0.8 and the ECHO handicap by 0.2 and add them. (This changes the handicap by 20% of the difference between the old handicap and the ECHO handicap) (Next Handicap = 0.8 x Handicap + 0.2 x ECHO)
From September 2015, the ratio of existing handicap and ECHO handicap is changed to 0.75 – 0.25. This is to increase responsiveness to significant changes to a boats performance. it is also the value recommended by the ISA and sail 100 author.