Result Calculation Notes

General

Process
Calculations
Course Correction
Yardstick Correction
PHS Correction
Multihull Correction
Points System
Abandoned Races
Duty Points

General

These notes are the compilers view of how the results are calculated. The notes are only to help club members (and the compiler) understand how the calculations are carried out and are certainly not meant to replace or alter the club sailing instructions which remain the definitive club sailing rule document.

The results are calculated in accordance with International Saling Rule guidelines and the rules of the Sugarloaf Sailing Committee. A set of Micorsoft Excel spreadsheets have been customised to meet the particular needs of the sailing program over one whole season so that the three series, Winter, Summer and Twilight are included. Also included are individual races such as the Marathon, Commodore's Cup, Parks Victoria Trophy and Club races. The published results on all web pages are provisional and subject to Sailing Committee endorsement at the end of the Season.

Process

The calculation process requires several fundamental sets of data.

1. Boat and skipper information compiled from previous races including the yardstick for each of the classes of boat sailed during the season.

2. The current PHS number for each boat/skipper combination.

3. The registration (sign on/off) sheet information which includes the skipper and boat information relevant to the particular race.

4. The timekeeper's time sheet information.

5. The finish line video tape.

The registration sheet and the timekeeper's time sheet are collected at least half an hour after the last boat finishes. Any obvious time sheet uncertainty is cleared up with the timekeeper after the race. The sign on sheet is compared with the time sheet ensuring all boats are accounted for. Those that did not start or did not finish the course need to be marked accordingly.

The boat data base is updated to include any new boats.
The series database is up dated to include any boats that had not previously sailed in the relevant series.
The race information is then entered. This includes weather and course details and the starting time for each division.

Individual boat information is then keyed into the relevant race fields in the series database. If a boat has not sailed the course correctly, as indicated in the declaration area of the registration sheet, a code is entered in accordance with the following table.

Condition	Code
Did Not Compete	DNC
Did Not Finish	DNF
Did Not Start	DNS
Disqualification	DSQ

The time sheet and video tape is a record of each boat's elapsed time for every South to North crossing of the sight line defined by the tower and the common mark. The video tape with its internal clock is run and compared against he timekeepers record. Any missing roundings or timing disparities on the timesheet are corrected and every sail number and time record is then entered into the the system. (Video tapes are archived for at least 10 weeks).
Having made all necessary entries, the system can then make the necessary time corrections (see "Calculations" below).

Boats are ranked in order of increasing corrected time. This determines the position of each boat in the race. This applies to both boats with skippers who are club members as well as visiting boats. The system calculates cumulative points (see "Points System" below) for the relevant race series. Up to 8 reports are generated for each race. Divisonal Yardstick and PHS Race Result, Divisonal Yardstick and PHS Progressive Aggregate Result and the same again for the Championship series. These reports are then saved as HTML pages ready for uploading to the Web Server.

Calculations

The system sorts through the elpased time and sail number lists and then counts laps for each boat. Discrepencies are made obvious so that anomolies such as missing laps can be queried.

There are two types of calculations performed, "Divisional" and "Championship". Divisional calculations determine a result for boats within predetermined groups and "Championship" results rank all boats.

Corrections are applied to both types of calculation in the following sequence:

1. Course Correction
2. Yardstcik or PHS Correction
3. Group Correction where applicable
4. Wind Correction where applicable

Course Correction

All classes sail a common triangular course in terms of distance and angle. The number of laps, however, depends on yardstick and is set such that classes are sailing the course for approximately the same time and therefore during the same weather conditions.

For example, faster classes will sail five triangles. Slower classes may only sail two triangles. The number of laps to be sailed for each class is available in the Sailing Instructions.

The start line is at or near the Club Common mark. This Common mark is common to all potential courses that may be set and is normally adjacent to the control tower where all roundings and finish line crossings are recorded as sail number and time. The common mark along with the tower alignment also describes the finish line. Lap splits are shown on each race result sheet.

The system identifies those common mark roundings that represent a complete triangle for each boat sailling each course. It finds the average lap time and multiplies this by the number of laps sailed by the fastest boat to create a time consistent with all boats sailing a common number of laps.

If there is not a compete triangle at the start as maybe expected in a race with a short start leg, this time is identified, adjusted proportionately and added to the above common lap, mean triangle time.

Shortened Course -

The salient reason for shortening races is reducing wind strength. At the time the decision is taken, boats are generally distributed around the triangle. With a range of classes sailing in up to 6 groups sailing a different number of laps, it is practically impossible to shorten the course for each group proportionately and certainly impossible to arrange the termination of the race so that boats sailing each course are on the water for exactly the same length of time. In varying wind strengths this time difference significantly effects the accuracy of the results.

To help overcome the problem, the system has a "built-in", objective mechanism to either accept or reject final laps for each boat such that the elapsed time spread is minimised. The bulk of the fleet is assumed to be finishing its shortened race at around the time that 84% of laps have been recorded. This then provides an arbitrary point representing when the bulk of the fleet has finished and is compared with each boats penultimate and last lap to determine which should apply and which should be rejected.

Yardstick Correction

Yardstick correction is to allow for the differences between boat performances based on class and some boat configuration changes within a class. This correction relies on the yardstick for each class.
Corrected Time = (100 X Elapsed Time)/Class Yardstick

Yachting Victoria yardsticks are generally used. One exception is the Yardstick for the Access 2.3 Servo class. Because of the limitations of a servo controlled boat, such as slower tacking and non servo actuated boom positioning on a run, 6 % is added to YV Access 2.3 (non servo) yardstick. This adjustment does not sufficiently cover the inability of an Access servo to reef while racing so a further adjustment of up to approx. 10%, is made depending on the strength and variablity of the wind.

Performance Handicap System (PHS) Correction

PHS correction allows for both boat class differences and skipper performance. PHS correction is an alternative to Yardstick correction. Only one or the other is applied producing two different sets of results.
For the PHS correction, the back calculated yardstick derived from each skipper's individual performance is used - described below
Sugarloaf Sailing Club uses a non-linear algorithm. This function changes the PHS approximately proportionally where BCYS changes are small but limits changes to a maximum amount as sailors make large apparent deviations in BCYS relative to their previous PHS number. This ensures statistical outliers are suppressed.
Hc = Hcp(1 + 2 X 10/B X Artan(100 X ((1-1/B)+0.2)*(BCYS-Hcp)/Hcp)/(100 X pi))

Current PHS number = Hc
Previous PHS number = Hcp
A weighting coefficient that limits sensitivity to BCYS changes = B (set to 100/(the number of boats starting)). If the number of either cats or dinghies is less than 5 then only the number of boats sailing in each of these respective groups is used).
BCYS (Back Calculated Yardstick for the skipper's most recent race) = Yardstick X (Corrected Time)/(Corrected Time of 3rd Place).
Corrected Time = (100 X Elapsed Time)/Current PHS number

Group (Multihull) Correction

A Group Correction, is applied to fleets comprising groups of boats that perform differently in varying conditions eg. monohulls and multihulls. This correction is found by subtracting the median of the 4 lowest corrected times for the multihull group from the median of the 4 lowest corrected times for the monohull group.
The Yardstick or PHS corrected time for each multihull is then further corrected by adding this Multihull Correction. The object is to align (or standardise) the finish time distributions at the median of the fastest 4 boats.
Since the Multihull Correction can give extraneous results for small groups, the Multihull Correction is set to 0 where either the monohull or multihull boat numbers are below 5.

Wind Correction

A Group Correction can also be applied to standardise displacement boats such as Access Dinghies and the Savage Dolphin. Since, however, we have never had 5 boats racing in these groups, we apply an alternative correction referred to as the Keel Boat Wind Correction. This is a yardstick factor derived from the calculated wind speed, the relevant keel boat's waterline length and data on keel boat performance relative to Sabre performance.

A similar yardstick factor based on catamaran versus dinghy performance data is applied to catamarans in those instances when there are insuffcient boats racing for the Group Correction (described above) to be applied. The data is based on over 100 races where the first 3 Sabres have been compared with the fastest catamaran. Only the fastest catamaran is used because of the smaller cat fleet size.

Wind speed is determined by using the average time of the 2nd fastest Sabres in a formula which has been derived from over 100 races of calculated average race wind speed versus estimated average race wind speed.

Points Allocation

For the purposes of determining position across a number of races that make up a series, points are allocated in accordance with the Low Point system.

Ranked Position	Points Allocated
1	0.75
2	2
2	2
3	3
n	n

Boats that fail to complete the course correctly are allocated the following points.

Code	Meaning	Points Allocated
DNC	Did Not Start (Did not Register)	No. of boats registered in the series plus 1.
DNS	Did Not Start (Failed to cross the start line within 10 mins of the start signal)>	No. of boats started in the race plus 1.
DNF	Did not Finish (Started but failed to complete the course)	No. of boats started in the race.
DSQ	Disqualification	No. of boats started in the race plus 1.

For the purposes of adding points across a number of races, the points are divided into two types. Those that are allocated as a result of disqualification and those that are allocated for all other reasons. The DSQ points are fixed and remain part of the total points for the series.

All other points are subject to a rule that allows the points for a certain number of races to be dropped from each boat's tally depending on how many races are in a series. The following table shows the number of races that must be counted.
There is a minimum number of races in which boats must race to be included in this points system and thus be eligible for a series position. The minimum number of races equals 50% of the number of Series Races + 1 (rounded down).

No. of Races in a Series	No. of Races to Count	Minimum No. of Races
4	3	3
5	4	3
6	4	4
7	5	4
8	6	5
9	7	5
10	8	6
11	8	6
12	9	7
13	10	7
14	11	8
15	12	8
16	12	9
17	13	9
18	14	10
19	15	10
20	16	11
21	16	11
22	17	12
23	18	12
24	19	13
25	20	13
26	20	14
27	21	14
28	22	15
29	23	15
30	24	16
31	24	16
32	25	17
33	26	17
34	27	18
35	28	18
36	28	19
37	29	19
38	30	20
39	31	20
40	32	21

The races dropped from the points tally are those that produced the highest points.
Boats will not appear in progressive result sheets until the minimum number of races have been sailed.

Duty Points

Average points representing a Skipper's performance, over those races in which he has completed without disqualification, are allocated to Skippers who are On Duty. The average is calculated from the total races sailed and includes points from races that may be subsequently dropped. The designation reported in the results is OD.

OD days are included in the tally for the minimum number of races in a series and for determining how many races can be dropped. Skippers have effectively sailed on OD days. OD points are not, however, eligible as dropped points.

Abandoned Races

Should a race be abandoned, the input to the system is zero whether the series entrant competed or not. Accordingly, categories such as DNC, DNF, DSQ do not apply and no time is entered. The race was effectively never scheduled nor sailed and unless it is resailed the number of races intended for the series will be reduced by one.