It goes without saying that studying weather is major part of an Around Alone sailors day. Some of them spend all their waking hours, when they are not sailing the boat, studying weather maps and planning strategy.
They can browse the Internet (any publicly available site) to get the latest weather information for their region, and for areas ahead so that they can plan their strategy. In addition to this most of the sailors are able to receive grib files which they can interpret with their navigational software to plan a route.
A grib file is a numerical file that can easily be sent via email. Because it's numerical it is a relatively small file, but one that holds a lot of information. Once the sailor has the file on board, he uses his software to "read" it, and the software turns the numbers into wind vectors. The vectors can be overlaid over a position chart so the sailor can see what kind wind he has, and what wind he can expect.
The skippers are also able to receive weather forecasts for as much as up to five days ahead. These also come as grib files, and this is where the fun really begins. With these forecasts, and special weather routing software, the sailors can start to look at various sailing options. The routing software has all the yachts performance data stored in the program. The performance data includes information about boat speed and the wind angles at which the boat performs its best. This data is constantly being gathered and updated because it's critically important for the skipper to know if he (or she) is sailing at or near his optimum performance. Without another boat close by to gauge speed, it's hard for the skipper to know if he is sailing as well as he could.
There is also another use for this performance data. By integrating the weather forecast with the performance data, the sailor can start to create different sailing scenarios. He can place his position where he thinks he would like to be in 48 hours and ask the software to tell him, based on the boats performance data, what the quickest way to get there is. The software looks at the boats polars (performance data), it looks at the forecast, and calculates the exact course the boat should sail to get to the where the skipper wants it to be. The sailor can also manipulate the forecast if he feels that the wind might be different, and he can also manipulate the weather if, for example, 24 hours later the wind is not exactly as was forecast. So you can see that this is a very valuable tool that helps the sailors navigate the often fickle weather patterns. Unfortunately weather forecasts are just that; someone's best estimate of what the conditions will be like a few days hence. Sometimes it does not turn out that way as Tim Kent on Everest Horizontal discovered yesterday. His log discusses some of the pitfalls of using the latest technologies.
"Well, I have inadvertently made my first big tactical error of the leg. Like every sailor in this race, I depend on weather files that I order up and then plug into the routing software that I use. The result is a really cool overlay of wind flags right on the chart so that I can see wind strength and direction over the area that I will be going in the next several days. For two days in a row, the weather files indicated that the traditional light airs associated with the doldrums were not present - a really nice pattern of wind from 15 to 20 knots dominated the area. The first time I saw this, I ordered another weather file several hours later to confirm this lovely weather. It did, as did the weather the next day - early Sunday morning. So I kept heading south, unlike virtually everyone else but Koji. But I grew suspicious, and late last night ordered up another file. WHOOPS - there were the doldrums - and I was sailing right into them! I fairly flew out of the cockpit and gybed the boat, heading west. I've been doing so all night and into today. The wind has shifted somewhat, so I may have to gybe back, but my predominanant movement today will be west. Better late..."
Positions at 0600 GMT, 05/11/02
||Bobst Group-Armor Lux
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