Skipper Handicaps : How they work .

(1) Why do we use skipper handicaps anyway

The aim of handicapping is to find out which skipper has improved the

most on time relative to the others he is racing against. And thus

reward him or her accordingly even if he or she didn't win the actual

race. Over the entire sailing season we want to find out who has

improved most often, on average, against the others.

Handicaps are adjusted each time a boat races. Every boat that races has

its elapsed time from start to the finish recorded.

Say we have three boats racing with elapsed times as follows:

1st Red, 27 minutes 30 seconds = 27 + 30/60 minutes = 27.50 minutes

2nd Blue, 28 minutes 20 seconds = 28 + 20/60 minutes = 28.33 minutes

3rd Yellow, 29 minutes 40 seconds = 29 + 40/60 minutes = 29.66 minutes

And, given that Red's initial skipper handicap rating is, for example,

0.978, Blue's is 0.954 and Yellow 0.874.

(2) To calculate handicap positions

The following formula is used to determine the corrected time:

Corrected Time (C) = Elapsed Time (E) * Handicap Rating (R)

Red C = 27.50 * 0.978 = 26.895 minutes

Blue C = 28.33 * 0.954 = 27.029 minutes

Yellow C = 29.66 * 0.874 = 25.929 minutes

Ranking the boats in order of corrected time Yellow would finish 1st on

handicap, Red 2nd and Blue 3rd. Thus, Yellow would score 1 point, Red 2

points and Blue 3, using the usual low point scoring system.

(3) To calculate ratings for the next race

We solve for R by using the winner's time, Red, as the desired corrected

time in the formula for Blue as follows:

27.50 = 28.33 * R

R= 27.50/28.33

R= 0.971

Similarly for Yellow

R = 27.50/29.66

R = 0.927

Red, the winner, will get a rating of 1 (R=27.50/27.50).

Handicap ratings will thus only range between 0 and 1.

(4) Weight the Rating to prevent huge fluctuations

These new values could be used for the next race. However, it would be

unfair if Red had won by a fluke chance. Also, we need to average out

the wind conditions as Red might only do well in a strong wind. We thus

weight the old handicap rating with the new one in the ratio 4:1. So

Red's new handicap would be (4 x 0.978 + 1 x 1.000)/5 = 0.982, Blue

would be (4 x 0.954 + 1 x 0.971)/5 = 0.957, and for Yellow = (4 x 0.874

+ 1 x 0.927)/5 = 0.885.

(5) Using the new weighted Rating for the next race

We use this weighted value of R for the next race to calculate the

corrected time, as we did in paragraph (2) above e.g. if the elapsed

times were 1st Blue in 31.50 minutes, 2nd Red 31.75 minutes and if 3rd

Yellow finished in 32.10 minutes.

Red C = 31.75 * 0.982 = 31.18 minutes

Blue C = 31.50 * 0.957 = 31.15 minutes

Yellow C = 32.10 * 0.885 = 28.41 minutes

Ranking in order of corrected time Yellow would finish 1st on handicap,

Blue 2nd and Red 3rd. Finally, Yellow would score 1 point, Blue 2 points

and Red 3, using the low point scoring system. Final positions in the

series on handicap would be worked out using the total of these scores.

The sailing instructions will determine the number of allowable

discards.

(6) Calculating new R values

We use the times from this race now to calculate new values for R as we

did in paragraph (3) above:

Red R = 31.50/31.75 = 0.992

Blue R = 31.50/31.50 = 1.000

Yellow R = 31.50/32.10 = 0.981

These are weighted with the 'old' ratings as we did in paragraph (4) so

that for the next race

Red R = (4 x 0.982 + 1 x 0.992)/5 = 0.984

Blue R = (4 x 0.957 + 1 x 1.000)/5 = 0.966

Yellow R = (4 x 0.885 + 1 x 0.981)/5 = 0.904

Etc, etc . Until it is as clear as mud! The more races that are

completed the closer we should approximate the skipper's "true" handicap

and the smaller will be the changes to the R value.

DNS, DNF, DSQ etc do not affect the handicap rating, the old value is

just carried forward. Any new skipper to the series will automatically

be awarded the lowest handicap rating of all the competitors in that

race.

(7) Using the ratings in Sailwave Race Scoring Software

First set the scoring properties. Go to SCORING SYTEM, RACE SCORING

click CUSTOM. Enter the following formulae C=E*R, E=C/R and R=C/E. Click

the TEST button to make sure they are functioning.

Enter the boats elapsed times using the SAIL NUM WIZARD. You must input

minutes decimal and then the seconds. Six seconds must be entered as 06.

Then double click on the elapsed time of first boat. Click the RATING

tab. Input your calculated rating for that skipper in the OVERIDE WITH

box. Do so for the rest of the competitors.

Click SCORE (F9) and this should do the trick. If you uncheck the CUSTOM

button and set scoring system to NONE you will get the scratch results.

Remember to rescore after the change. This way you need only one race

file and thus enter data only once to calculate both the scratch and

handicap positions. You can do it for different fleets within the same

race.

Note that when you are calculating a series Race 1 should be excluded

from the handicap series as you won't have a rating for the first race.

Good luck.

Rob Walker