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Wednesday Explanation

Wednesday Explanation

Objectives

The aim of the Wednesday evening series is to provide racing which is inviting to members who have little or no racing experience; yet challenging and competitive to those who have been racing for years.

Format

The race format is a single-fleet, pursuit race.

Slower classes of boat start first with faster classes starting later. The race runs for a fixed duration of 70 minutes. At the end of this time, the boat which is at the front is the winner.

In addition, each helm may have their start time adjusted to be either earlier, or later than the "scratch" start for the class of boat they are sailing. In this way, new racers are given a greater chance of success while the fast helms are faced with the challenge of working through the fleet.

Before the Start

There are a few things to do before the start of the race:

  1. Order Supper. Wednesday evening are a fairly social affair, Antony does a great job with the "Sailors' Suppers" but please remember to place your order before the race.

  2. Check your start time. See below for more information about start times but do remember to check them each week. You will need this in order to...

  3. Sign On. The signing on sheets are in the race-hut on the North edge of the clubhouse. Please sign on clearly and ensure that your sail number is correct. This will help Pat no end when entering the results.

  4. Check the course. The course is displayed on the front of the club house under the balcony. The buoys are numbered anticlockwise from number 1, outside the clubhouse, round to 13 (See this map). There are also a couple of lettered buoys which can be moved so use the map on the course board. Note that the course on the only club house is a guide, and can be changed. Make sure that you verify that the course on the stern of the committee boat.

  5. Launch with plenty of time. Most of us find time difficult mid week. However, especially for your first few races, make sure that you have plenty of time. Don't wait for the boats around you to launch as they may have much later start times.

  6. Sail the course. If you have time, make sure that you know where all the buoys are. The best way to be sure is to sail some, or all, of the course. Keep an eye on the time, as missing your start definitely won't help but it is surprising how much can be gained by having sailed some of the legs before you have to do it in earnest.

Start

The start line will almost always be between the committee boat and a small white or orange buoy (with a stick through it and a flag or a ball on the top) positioned approximately 50 yards from the Port side of the committee boat. The line will usually be set fairly square to the wind and the first leg will be a beat.

Check for special instructions on the course board as things can change but the above will give you a reasonable starting point.

The initial start sequence in a six minute warning signal (Flag G ) followed by a three minute preparatory signal (Flag P ). When both flags are lowered the 70 minute race commences.

New for 2005 is the addition of an electronic timer and numeric display. The display will be located on the coach roof of the committee boat facing aft. This display will start at -6 when the G flag is displayed six minutes before the first start, it will then count down to zero at the first start. After that, it will start to count up if half minute units.

At the start of the race, only the Optimists actually get going. All other classes wait until their start is displayed on the number boards on the committee boat. These numbers start at zero (as mentioned above) at the beginning of the 70 minutes and count up.

All boats start when their time is displayed. This is an important change from previous years where boats used to start when their time was covered up.

Let me repeat that:

Start when your time is displayed, not when it is covered up.





Finish

The best way to finish a pursuit race of this type would be to take an aerial photo at exactly 70 minutes after the start. The start times are calculated for a 70 minute race so if we could freeze time then, we would have the perfect finish.

Clearly, that is not feasible so we use the next-best thing: A finish line which is set where the front boat happens to be after 70 minutes and then tracks back through the fleet. One minute before the actual finish, the committee boat will sound a hooter and display the S flag . One minute later (exactly 70 minutes after the start) the first boat will finish.

The finishing line is usually between the committee boat and the rescue boat. If this is the case, you should sail between the two boats. The sailing instructions also allow for the finish line to be a line extending, perpendicular to the course, either side of the committee boat. This will be used when the rescue boat is occupied, in which case all competitors should finish reasonably close to the committee boat.

Finishing a large fleet like this can be tricky for the race officer. Here are a few things which everyone can do to help:

  • Make a mental note of the boats around you so that we can check positions later.
  • Ensure that your sail number can be seen (if finishing on a broad reach, for example, sheet the main in as you finish so that the race officer is not viewing your sail from the edge.
  • If finishing on a beat, stay near the middle of the course. The finish line can only be made so wide to accommodate the possible upwind options.
  • Keep sailing straight on after the finish until you are sure that you have been recorded.

Where there is doubt about finishing positions, they will be resolved in favour of the slower boat. This is in keeping with the theoretical "Instant Finish after 70 minutes" which is what we are trying to achieve.

After the Race

The bar is open and supper is served - Enjoy!

Collating the results can take a little while so please allow the race officers some space to get the job done. When they are done, feel free to take a look and check that you are in roughly the right place. Mistakes are easier to rectify straight away.

No promises, but we try to get the results up on the Web sometime on Thursday.


Full Sequence

Time Action Number displayed Sound Flag  
6:41:00 Start of Sequence -09.0 Long None
6:44:00 Warning Signal -06.0 Long G raised
6:44:30   -05.5 Short    
... ... ... Short  
6:47:00 Preparatory Signal -03.0 Long P raised ↑ 
6:47:30   -02.5 Short    
... ... ... Short  
6:50:00 First Start  00.0 Long G and P lowered ↓  ↓ 
6:50:30 Second Start  00.5 Short    
6.51:00 Third Start  01.0 Short    
... ... ... Short  
7.59 Warning of Finish  69.0 Long S raised ↑ 
8.00 First boat Finishes  70.0 Short    

Personal Handicaps

Personal handicaps are used to make the racing more even. We do not want the fast sailors to get bored by always winning or the new comers to get frustrated following them around.

In order to make the personal handicaps completely objective, they are solely based on each helm's previous results in this series. We run a small program over the results and this calculates an adjustment for each helm. This will be in terms of a number of minutes either before (a negative number) or after (a positive number) the start time for their class.

Note that we run this program after every race so your start time could change after every race. In general terms, if you finish in the front half of the fleet, your handicap will go up (you will start later), if you finish in the back half of the fleet, your handicap will go down (you will start earlier). The exact amount of the adjustment will vary depending on your actual position and the size of the race. Winning a race of 50 boats will adjust your handicap by approximately one minute.

Your start time is decided by a combination of the handicap for your class of dinghy and your own personal handicap. Simply add them together. For example, take an experienced Enterprise sailor with a personal handicap of +2:


Enterprise 23
Personal +2

Start Time 25




This sailor would then start when the number 25 is displayed on the committe boat.

For those who are new to the series, or those who have changed boats, we will need to assign you with an initial personal handicap. Initially, it can be anything from -2 to +2 depending on your level of experience. Just follow these guidelines:

  • If you are new to racing, use -2 minutes, this will give you a bit of a head start.
  • If you are a reasonably competent club racer, start from the scratch time for your boat.
  • If you are a competitive racer comfortable at open meetings, use +2 to give yourself a challenging race.

Of course, you can use -1 and +1 if you fit in the middle somewhere.

Note that most people in the fleet will already have personal handicaps from previous years so you are just trying to pick a number which will slot you in at the right place. If you are not sure .

Personal handicaps and start times are displayed on the Results page and on the notice board upstairs in the club house. In addition, there is a more detailed set of results which shows the progression of the personal handicaps, in seconds, throughout the series.

All results count towards the personal handicaps, even those which are discarded from the series. There will be a prize at the end of the season for the person which the highest personal handicap.



Complicated?

Well, it may seem so but actually it really isn't.

Here is the bit which you wish had been at the top:

  1. The first time you race: Look up in the "70" column here for your start time.
  2. For subsequent races: Look in the "Personal Start" column against your name here.
  3. Start when your number is displayed.
  4. Stop when the finish line drives past.
  5. Above all: Please ask if you are not sure.

Enjoy

That's the key, have fun with the sailing. If it isn't fun, please let us know.

P.S.

For those people who are interested, the exact details of the formula used to calculate the personal handicaps is given below. This is not required reading but a few people have asked and I strongly believe that this information should be public knowledge.

We take the distance of your result from the midpoint of the fleet as both a count and as a percentage of the fleet size. These are then multiplied by a couple of constant factors and added together to give an adjustment in seconds.

The factors, or magic numbers, were agreed by analysing a large number of possible combinations. Weighting the factor applied to the count means that the fleet size has a large impact, weighting the factor applied to the percentage means that the fleet size has less impact. We chose 3 and 0.6 respectively for 2004 and this seemed to give a reasonable spread and give approximately a 1 minute adjustment in a 30 boat race. For 2005, these have been reduced to 2 and 0.4 which makes the system about 30% less aggressive and should smooth out the weekly fluctuations. We are able to do this as we have the 2004 handicaps as a starting point.

For 2008, the formula has been updated to ensure that all time adjustments are realative to the length of the race for the boat in question. This has been done to address the fact that 1 minute very significant if you are sailing a 35 minute race but has a smaller impact if you are sailing a 70 minute race. See the end of the formula below.

Anyway, down to the nitty gritty, the exact formula is as follows (this is simplified slightly in an attempt to keep it clear):

Let

F = No of Finishers
R = Result (finishing position in race)
A = Adjustment (seconds)
M1 = 3 (was 3 for 2004)
M2 = 0.6 (was 0.6 for 2004)

Then

D = Distance from midpoint
= (F / 2) - R
P = Percentage from midpoint
= 50 - (R / F * 100)
A = (D * M1) + (P * M2)



So, as an example, take a sailor who finishes 2nd in their first race of 49 boats:

F = 49
R = 2
A = Adjustment (seconds)
M1 = 2
M2 = 0.4

Then

D = Distance from midpoint (rounded)
= (F / 2) - R
= (49 / 2) - 2
= 23
P = Percentage from midpoint
= 50 - (R / F * 100)
= 50 - (2 / 49 * 100)
= 45
A = (D * M1) + (P * M2)
= (23 * 2) + (45 * 0.4)
= 46 + 18
= 64

For 2008, the following is then applied:

Let

L = Length of the previous race for this boat
T = Length of a race for a boat starting on 25
= (70 - 25) * 60 (seconds)
= 2700

Continuing our example from above. Let's assume that the boat in question was a Solo which has a class start time of 21 and that their personal handicap prior to this race was -1.5

L = (70 - 21 - 1.5) * 60 (seconds)
= 47.5 * 60 (seconds)
= 2850
A' = A * L / T
= 64 * 2850 / 2700
= 68

Which means that their personal handicap is +68 seconds. This is converted to a start time by rounding to the nearest half minute (1.0, in this case) and adding it to the class start time. For the next race, a similar calculation is performed and then added to this result. So, although the fact that 68 seconds has been rounded down to 1 minute, adding a mere 8 seconds in the next race will take the start time up to +1.5.



Created on 28/11/2005 06:42 PM by Burghfield Admin
Updated on 11/04/2013 08:27 AM by Ian Bullock
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