Concord Ryde Sailing Club Handicap System
Objectives
The objective of the handicap system is to give every boat an equal chance in every race.
The Maths
The calculations and some tables are at the end of these notes
What the numbers mean.
The handicap for each boat is a number which by which the elapsed time is multiplied to give a corrected time.
For a handicap start, this number needs to be converted into a number of 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.
How the handicaps are calculated
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 makes adjustments 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
www.sailing-old.com/inside/default.asp?pageId=70
Appendix 2 and 4 and Echo management guidelines
Handicap to minutes
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.
Handicap to Minutes Minutes to Handicap
Mins = (1-HCP)/HCP*100 HCP = (mins/100)/(1+mins/100)
|
Handicap |
Mins |
|
Mins |
Handicap |
|
1 |
0.0 |
|
0 |
1.0000 |
|
0.99 |
1.0 |
|
1 |
0.9901 |
|
0.98 |
2.0 |
|
2 |
0.9804 |
|
0.97 |
3.1 |
|
3 |
0.9709 |
|
0.96 |
4.2 |
|
4 |
0.9615 |
|
0.95 |
5.3 |
|
5 |
0.9524 |
|
0.94 |
6.4 |
|
6 |
0.9434 |
|
0.93 |
7.5 |
|
7 |
0.9346 |
|
0.92 |
8.7 |
|
8 |
0.9259 |
|
0.91 |
9.9 |
|
9 |
0.9174 |
|
0.90 |
11.1 |
|
10 |
0.9091 |
|
0.89 |
12.4 |
|
11 |
0.9009 |
|
0.88 |
13.6 |
|
12 |
0.8929 |
|
0.87 |
14.9 |
|
13 |
0.8850 |
|
0.86 |
16.3 |
|
14 |
0.8772 |
|
0.85 |
17.6 |
|
15 |
0.8696 |
|
0.84 |
19.0 |
|
16 |
0.8621 |
|
0.83 |
20.5 |
|
17 |
0.8547 |
|
0.82 |
22.0 |
|
18 |
0.8475 |
|
0.81 |
23.5 |
|
19 |
0.8403 |
|
0.80 |
25.0 |
|
20 |
0.8333 |
|
0.79 |
26.6 |
|
21 |
0.8264 |
|
0.78 |
28.2 |
|
22 |
0.8197 |
|
0.77 |
29.9 |
|
23 |
0.8130 |
|
0.76 |
31.6 |
|
24 |
0.8065 |
|
|
|
|
25 |
0.8000 |
|
|
|
|
26 |
0.7937 |
|
|
|
|
27 |
0.7874 |
|
|
|
|
28 |
0.7813 |
|
|
|
|
29 |
0.7752 |
|
|
|
|
30 |
0.7692 |
Calculation of handicap for following race.
Next Handicap = 0.8 x Handicap + 0.2 x ECHO
The practical effect of ECHO is best shown by example.
A fleet consists of 5 boats with the following handicaps (TCF) and results in a race.
Boat HCP Elapsed Time
A 1.000 DNC
B .9500 95 Mins
C .9200 100 Mins
D .9000 101 Mins
E .8700 104 Mins
|
|
Elapsed |
HCP |
Corrected |
New HCP |
|
B |
01:35:00 |
0.95 |
01:30:15 |
0.9493 |
|
C |
01:40:00 |
0.92 |
01:32:00 |
0.9158 |
|
D |
01:41:00 |
0.90 |
01:30:54 |
0.8980 |
|
E |
01:44:00 |
0.83 |
01:26:19 |
0.8369 |
Let us consider the impact of this race on each boat in turn.
Boat A did not sail, so its handicap remains 1.
Boat B had a fair race, coming second on handicap. B’s handicap rises by 0.07%, (lower TCF) which is hardly moving.
Boat C had a bad race, coming last on handicap by a minute. C’s handicap got larger (lower TCF) by 0.42%
Boat D had a fair race, coming 3rd on handicap. D’s handicap decreases by 0.2%.
Boat E had a great race, winning on handicap by 4 minutes. E’s handicap is reduced 0.69%. (Higher TCF)
What does this mean in minutes?
|
|
HCP Old |
Min :Sec |
HCP New |
Min :Sec |
Change |
|
B |
0.95 |
05:16 |
0.9493 |
05:21 |
00:05 |
|
C |
0.92 |
08:42 |
0.9158 |
09:12 |
00:30 |
|
D |
0.90 |
11:07 |
0.8980 |
11:21 |
00:15 |
|
E |
0.83 |
20:29 |
0.8369 |
19:29 |
01:00 |
ECHO Procedure
|
|
|
|
|
|
|
Base = |
1:40:00 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
|
|
ECHO |
|
|
|
Boat |
Elapsed |
HCP |
Corrected |
|
Step 1 |
Step 2 |
Step 3 |
|
New Hcp |
|
B |
1:35:00 |
0.95 |
1:30:15 |
|
1.052632 |
0.89904 |
0.946358 |
|
0.949272 |
|
C |
1:40:00 |
0.92 |
1:32:00 |
|
1 |
|
0.899040 |
|
0.915808 |
|
D |
1:41:00 |
0.9 |
1:30:54 |
|
0.990099 |
|
0.890139 |
|
0.898028 |
|
E |
1:44:00 |
0.83 |
1:26:19 |
|
0.961538 |
|
0.864462 |
|
0.836892 |
|
|
|
|
|
|
|
|
|
|
|
|
Sum |
|
3.6 |
|
|
4.004269 |
|
3.6 |
|
|
Step 1.
Divide elapsed time by base time for each boat.
Step 2.
Divide sum of handicaps by sum of step 1
Step 3.
Divide step 2 by step 1 for each boat.
Step 3 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.
To 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)
Paul Gurr
Handicapper Nov 2011