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Monday 19 April 2010
Sunday 18 April 2010
Club Handicaps & Bostock Cup
To track and record my sailing progress, I have decided to publish the race results and how I have performed against handicap. I will advise that this is purely for my own reference and interest.
I have used the Results Worksheet which is published on the RYA worksheet and put together by the Portsmouth Yardstick Advisory Committee. If you like me are interested in statistics it provides fascinating results.
Standard Corrected Handicap
The way it works is as follows....
For any given race, there will be an unknown theoretical ‘best possible’ corrected time that could be achieved by a boat sailing perfectly, tacking on the right wind shifts, avoiding adverse currents, etc. In practice boats are not perfect and their crews make mistakes that cause them to sail slower than this optimum. The resultant distribution of corrected times across a fleet will typically be ‘skewed’ since it is easier to make mistakes than to avoid them. A few boats may come close to the theoretical achievable time, some will make an average number of mistakes & there will be a diminishing tail of slower boats making increasing numbers of errors. Performance assessment requires a comparison standard against which to measure each boat. If this standard is simply the average of all corrected times in a skewed distribution, it will be weighted towards the poor performance end and the majority of boats will appear to have sailed better than ‘average’, distorting the assessment. The performance standard is defined instead as the corrected time achieved by the largest group of boats; that is the peak or ‘mode’ of the distribution. Boats that achieved this Standard Corrected Time (SCT) will have sailed ‘to handicap’.
Click on image for more detail
The YR2 procedure allows for the typical 'skewed' distribution in calculating the SCT. The average of corrected times for the top two thirds of the PY, SY & RN boats in the race gives the Average Corrected Time (ACT). ACT+5%, corresponding to the statistically average performer relative to handicap two thirds down the fleet, defines the 'poor performance' limit. The corrected times of all PY, SY & RN boats faster than ACT+5% are then averaged to give the SCT for the race. This new group of boats may be the same as the original two thirds or more or less, depending on the performance distribution in each race. The elapsed time for each boat is divided by the SCT and multiplied by 1000 to give its 'achieved performance'. Corrected times worse than ACT+5% are defined as 'poor' and should be excluded in calculating a boat's average performance for handicap assessment.
PY Handicaps
The handicaps I have used are those published by the RYA. The one assumption I have made in my calculations is that the handicaps of the Wivenhoe Ones are well established and can be included in SCT calculations.
Bostock Cup Results
Click on image for more detail
Handicaps and statistics are very interesting things. The Xenon crossed the finish line second, came 8th out of the club handicaps and 4th in the RYA handicaps (2.3% above par on today's sail).
If you spot any obvious errors let me know.
I have used the Results Worksheet which is published on the RYA worksheet and put together by the Portsmouth Yardstick Advisory Committee. If you like me are interested in statistics it provides fascinating results.
Standard Corrected Handicap
The way it works is as follows....
For any given race, there will be an unknown theoretical ‘best possible’ corrected time that could be achieved by a boat sailing perfectly, tacking on the right wind shifts, avoiding adverse currents, etc. In practice boats are not perfect and their crews make mistakes that cause them to sail slower than this optimum. The resultant distribution of corrected times across a fleet will typically be ‘skewed’ since it is easier to make mistakes than to avoid them. A few boats may come close to the theoretical achievable time, some will make an average number of mistakes & there will be a diminishing tail of slower boats making increasing numbers of errors. Performance assessment requires a comparison standard against which to measure each boat. If this standard is simply the average of all corrected times in a skewed distribution, it will be weighted towards the poor performance end and the majority of boats will appear to have sailed better than ‘average’, distorting the assessment. The performance standard is defined instead as the corrected time achieved by the largest group of boats; that is the peak or ‘mode’ of the distribution. Boats that achieved this Standard Corrected Time (SCT) will have sailed ‘to handicap’.
The YR2 procedure allows for the typical 'skewed' distribution in calculating the SCT. The average of corrected times for the top two thirds of the PY, SY & RN boats in the race gives the Average Corrected Time (ACT). ACT+5%, corresponding to the statistically average performer relative to handicap two thirds down the fleet, defines the 'poor performance' limit. The corrected times of all PY, SY & RN boats faster than ACT+5% are then averaged to give the SCT for the race. This new group of boats may be the same as the original two thirds or more or less, depending on the performance distribution in each race. The elapsed time for each boat is divided by the SCT and multiplied by 1000 to give its 'achieved performance'. Corrected times worse than ACT+5% are defined as 'poor' and should be excluded in calculating a boat's average performance for handicap assessment.
PY Handicaps
The handicaps I have used are those published by the RYA. The one assumption I have made in my calculations is that the handicaps of the Wivenhoe Ones are well established and can be included in SCT calculations.
Bostock Cup Results
Handicaps and statistics are very interesting things. The Xenon crossed the finish line second, came 8th out of the club handicaps and 4th in the RYA handicaps (2.3% above par on today's sail).
If you spot any obvious errors let me know.
Thursday 15 April 2010
How to Plane
So I have been going on about planing recently and have found the following top tips which we'll be putting into effect in the next race..... planing can happen in a suitably designed boat in moderate to strong winds if the crew do some or all of the following:
- Sail on a reach or broad reach to begin
- Slacken the jib
- Raise the centreboard
- Increase the speed
- Keep the hull level, trapeze if necessary
- Observe the wake until it is smooth and fast.
- Move the crew weight increasingly towards the rear to begin and to sustain planing
- Sheet in as speed increases, and apparent wind correspondingly moves forward.
- Keep the boat flat and level
- Bear away to maintain speed as necessary
- Flick or pump the sails (although there are restrictions on doing this in a race)
Wednesday 14 April 2010
How Fast Does a Topper Xenon go?
Now that I am in my second season of racing the Topper Xenon, I am starting to get interested in just how fast we might be going!
There is a formula for calculating the maximum hull speed of a boat which is....
HSPD = maximum hull speed in knots
LWL = hull length in feet at waterline
I will need to make a few minor assuptions - the length of the Topper Xenon is 4.5m and this will be assumed to be the LWL which in feet = 14.764ft
HSPD therefore = 4.37 knots (8.1kph or 5.02 mph)
Now here's the real key thing to understand about how you are going to win races. You have got to learn to plane because when you do the formula goes out of the window.
There is a formula for calculating the maximum hull speed of a boat which is....
HSPD = maximum hull speed in knots
LWL = hull length in feet at waterline
I will need to make a few minor assuptions - the length of the Topper Xenon is 4.5m and this will be assumed to be the LWL which in feet = 14.764ft
HSPD therefore = 4.37 knots (8.1kph or 5.02 mph)
Now here's the real key thing to understand about how you are going to win races. You have got to learn to plane because when you do the formula goes out of the window.
Sunday 11 April 2010
Spinnaker Sailing
I think we must have been a little reluctant to use the spinnaker after our near miss last week and our slight draining of confidence.That however changed in today's race..
Today's Wind (Race Start 9:30)
Xenon Spinnaker Sailing
After seeing the WODs and the Flying Fifteen putting up their spinnakers we realised that we probably should do the same. If only we had done sooner. The lesson learned today were
I'm convinced somewhere there is a list of all the things that could possibly go wrong when you sail. As you learn to sail, you experience each one of these things on the list until you have crossed them all off and are a competent racer. Today we also learned to make sure we both know explicitly the race course and to continue to treat the mud banks with caution.
The above paragraph indicates where it went wrong today, we were running second behind the Flying Fifteen but hit the mud and let the WODs catch us, then after overtaking them we decided to go round an extra buoy (rats).
Today's Wind (Race Start 9:30)
After seeing the WODs and the Flying Fifteen putting up their spinnakers we realised that we probably should do the same. If only we had done sooner. The lesson learned today were
- provided you are on a near run, you should be ok
- you are going to get blown over if you treat your asymmetric spinnaker like a genoa. So that means when you do find yourself going over, you have got to turn down wind as soon as you can (I'm sure there is more theory to this and I'll look it up during the week.
- when you do go on the plane, the whole boat lifts out of the water and the tiller becomes very sensitive - it becomes easy to crash if you are not careful.
I'm convinced somewhere there is a list of all the things that could possibly go wrong when you sail. As you learn to sail, you experience each one of these things on the list until you have crossed them all off and are a competent racer. Today we also learned to make sure we both know explicitly the race course and to continue to treat the mud banks with caution.
The above paragraph indicates where it went wrong today, we were running second behind the Flying Fifteen but hit the mud and let the WODs catch us, then after overtaking them we decided to go round an extra buoy (rats).
Wednesday 7 April 2010
10 Reasons why you'll never beat a Wivenhoe Sailor
They are used to the following conditions ....
- Mud banks appearing out of nowhere
- Strong tides
- Massive tidal ranges
- Gusty winds
- Narrow channels
- National class champions
- Estuarine conditions, both river and sea
- They have their own One Design
- Fiercely competitive club races every weekend
- You don't know the Colne
Sunday 4 April 2010
When to use the Spinnaker
The Season has started again and I am back at the helm with the Barman crewing!
To start the 2010 Season, here's a few lessons learned about today's 'Can Race' at Wivenhoe Sailing Club.
The spinnaker on the Topper Xenon is both a race winner and race looser. Depending on your level of experience it could go either way but I reckon if you can use it you should and there is no other way of getting experience than trying it out.
Today's race adventure started as we headed south down the Colne and I got the Barman to put the spinnaker up. Yes we had it rigged right for once and it went up really well. I now realise we were on a bit too much of a reach to control it and we overpowered. This is when the fun started and the Barman was hanging on the side of the boat with me thinking yikes where is the safety boat....
Can Race at Wivenhoe Sailing Club
At Wivenhoe SC, this means you have to go round every buoy on the course, and with today's wind we went up to Rat Island opposite Brightlingsea - a long course.
Lessons Learned for Spinnaker
To start the 2010 Season, here's a few lessons learned about today's 'Can Race' at Wivenhoe Sailing Club.
The spinnaker on the Topper Xenon is both a race winner and race looser. Depending on your level of experience it could go either way but I reckon if you can use it you should and there is no other way of getting experience than trying it out.
Today's race adventure started as we headed south down the Colne and I got the Barman to put the spinnaker up. Yes we had it rigged right for once and it went up really well. I now realise we were on a bit too much of a reach to control it and we overpowered. This is when the fun started and the Barman was hanging on the side of the boat with me thinking yikes where is the safety boat....
Can Race at Wivenhoe Sailing Club
At Wivenhoe SC, this means you have to go round every buoy on the course, and with today's wind we went up to Rat Island opposite Brightlingsea - a long course.
Lessons Learned for Spinnaker
- The Topper Xenon's spinnaker is huge so if the winds aren't light and you are not on a broad reach it is going to overpower you.
- Don't put it up if it is blowing F4-5 (just yet anyhow!).
- If you are starting to loose it, get over the side asap and on that centre board (easier for the crew!).
- If your crew goes in the water and you are left onboard try to..
- drop the spinnaker
- point to wind
- lower the centre board fully
- furl the jib
- haul in spinnaker
- haul in crew
- avoid ditching as it will be a nightmare righting it with the spinnaker in the water and the wind.
- Keep your eye on the more experienced crews to see what they are doing.
The wind speed above is average wind speed and represents an average of F4.
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