Vendee Globe - Little wind for Ari Huusela. Forecast error. GRIB files. Radar reflectors and transponders.
As he expected Ari is in a high pressure area with very light winds. Here he has to use every trick he can to capture the slightest puff of wind that might help carry him gradually Eastwards. However it is dark and those winds are so light that perhaps it's as well to wait until morning. For now perhaps he can get some much needed rest, leaving his Radar and AIS on watch.
How good a sleep can you get though, knowing that there are boats out there with their AIS turned off? At least on the bridge of a ship there is usually a regular watch kept. At least there should be. What about those fishing boats? Sleepy after a busy night, heavy meal? Siesta? This isn't the North Sea after all...
Terrestrial AIS records show Ari's boat "Stark" off of West Africa. That was a long time ago, so I can't easily show his position with respect to other traffic but the satellite AIS will be visible to other vessels. As well as a radar,
IMOCA yachts carry a radar reflector and a radar transponder (explanatory videos below) to increase their visibility to other vessels. These are mounted at least 5m above the water line. For those interested, all manner of safety stipulations and mandatory equipment are listed in the
class rules.
Back to the weather. There is a forecast anomaly for 0900 Tuesday which is absolute nonsense. Ignore it. Perhaps they will spot it in the morning.
I'm not going to paste a load of maps here as the situation is a bit patchy and subject to revision. Ideally we would look at several weather models but this is what we have for now. There are a lot of opportunities to be in weak or oppositional winds over coming days. That's frustrating. Maybe there is an opportunity around midday. The winds won't be strong but may allow some progress to be made.
If anyone is interested in these GRIB files and would like to have a look at them, you can get both open GRIB files and software to read them with from
OpenGribs - Home OpenGribs - Gribs
Manoeuvring in fickle winds in a busy part of the sea requires care and communication with other boats. Using the engine is not an option unless in an emergency and that would mean forfeiting the race.
The following videos do not describe the exact equipment used on IMOCA yachts but are intended to give an idea of the general principles.