The race tracker is a great way to follow the action in offshore sailing races where the competitors are too far away to see, such as the current New York Vendée transatlantic race which started on Wednesday.
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There are lots of interesting and useful features, which can seem bewildering at first. So this is a quick guide to explain what the tracker shows.
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How Does The Tracker Work?
Each yacht carries a specialist beacon which transmits its precise position, direction and speed at pre-determined intervals. The race committee receive regular updates – also called ‘pings’ which helps them monitor the race closely. For the public, the tracker is updated hourly.
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At the bottom of the tracker is the date stamp (in French time for this race). If this time is more than one hour old, simply refresh your browser to ensure the most up-to-date information is displayed.
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Why Hourly?
The skipper and their shore team see the same information. The hourly gap means that boats don’t know the exact positions of their competitors. Even though the boats look close on the tracker they can be tens or hundreds of miles apart and not visible to each other.
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In some other races there are ‘blackouts’ which reduce the update frequency even more at key times to ensure skippers make their own tactical decisions without looking at what everyone is doing!
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The interval reduces to every 15 minutes when boats are in the proximity of the start or finish line when knowing the exact position is more critical.
The Main Screen
The main screen shows an aerial view of the position of each competing boat. Each team has a colour which roughly represents their colours in real life so they are easier to identify. Ollie (highlighted) is white with red and black.
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2. The Boats
Some boats have little bits sticking out the side. These represent the foiling yachts.
This is a slightly different boat design than Ollie’s. Foils are a modern concept allowing the boat to lift out of the water and ‘fly’. This means less boat surface area is in contact with the water so they sail significantly faster – but they are more expensive, add complexity and are disadvantageous in very light or very heavy wind and sea conditions. Â
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This creates an interesting split in the fleet. About 1/3 of the fleet do not have foils (including Ollie). In the results, there is no consideration or handicapping system to differentiate between foiling or non-foiling IMOCA 60 yachts.
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3. Boat Track
Behind each boat is a pale line, which turns solid when a particular boat is selected. This shows the track of each boat, making it easy to see the route they sailed and where and when each skipper chose to tack or gybe (change direction).
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4. Rhum Line
The line from New York to the finish at Les Sables d’Olonne is the Rhum line. This is the shortest possible route (allowing for exclusion zones, turning marks or hazards) and boats generally aim to follow it closely, as it is obviously preferable to sail less distance. Of course, in reality, boats can only sail at certain wind angles and skippers will have to choose whether to sail ‘further but faster’ or stick closer to the Rhum line. Â
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5.  Control Panel
On the right-hand side are a few controls offering zoom in or out, to move the map or centralise the map around the highlight boat depending on your viewing preferences. There is also a ruler and a full screen option.
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6.  Wind Overlay
Selecting the yellow button labelled  ‘Winds’ as a visual overlay of the wind to provide an insights in to the conditions faced by the boats. Simply select the time interval from current to +24 hours to view the forecast.
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7. Wind legend
The colour gradient indicates the strength of the wind in knots. When it is dark blue there is very little wind (under 5kts) and the boats will struggle to move, especially those with foils. Green is ideal and red is very rough and stormy. Â The moving arrows on the screen demonstrate the direction.
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8. Skipper Panel.
On a computer this shows automatically on the left-hand side. On mobile view, it shows the skipper in Position 1 by default, Â tapping the little arrow to the side, brings up the full list.
‘03’ – the 2-digit number shows the current position of that selected skipper in the fleet, based on distance to finish. In this race there are 28 competitors. The red, green or grey arrows indicate if the skipper is moving up or down the rankings, or staying still.
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The bottom line of numbers are the precise data from the beacon including –
·     The exact time of the ‘ping’ – this may vary slightly between boats
·     Boat heading as a numerical compass value eg 144 degrees is South East
·     Current boat speed in knots (nautical miles per hour)
·     Distance to go to the finish (in nautical miles)
·     Distance behind the leader
Selecting a specific yacht (by hovering over it on a computer, or tapping on a mobile) brings up this same information, but provides additional 4-hour and 24-hour performance averages.
It is particularly useful to compare the boat speed with VMC. Speed is how fast the boat is moving whereas VMC indicates rate of progress towards the destination.
VMC stands for Velocity Made Course, and can also be called VMG. The aim is for VMC to be as close to boat speed as possible. A high boat speed and low VMC means a boat is sailing fast but not in the best direction. A negative VMC would mean the boat is sailing in the wrong direction completely, getting further away from the finish.
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9. Favourite Filter
Starring a skipper and then selecting the favourite filter changes the main display to only show the selected boats.
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10. Time Stamp.
This panel shows the time (in Central European Time) of the information used in the main display. If this is more than 1-hour old, refresh the browser to view the latest information.
11. Timeline
Finally at the bottom of the tracker is the scroll bar – drag this from side to side to rewind and replay!
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Make sure you bookmark the race tracker, you’re going to be checking it regularly!
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