World Pilot Charts – They’re vital for passage planning and therefore yacht deliveries. – Have you ever used them before? – Do you know how to use them?
I’ve found them invaluable, and so thought to put together a basic guide to their use.
This is an excerpt for the month of June in the North Atlantic.
We’ll start with the blue wind roses.
They represent the average of the prevailing winds, in that 5degree area for that month.
The length of the arrows shows the percentage of days in that month that the wind blows from that direction, the length of the arrow (in particular its stem, not the feathers gives you the percentage, the scale for length can be found on the chart.) The arrows fly with the wind. The number of feathers, represent the average Force of wind on the Beaufort Scale.
Here’s a specific example. Off the coast of Spain.
You can very quickly get an idea of what to expect when Sailing in this area.
In short, If you were sailing South you would have a good chance of very favourable breeze. You will most likely be on a Starboard Reach, sailing in a F4. Note 4 feathers on almost all arrows.
So lets look at a specific arrow if you’re still a bit confused. The South East arrow, shows you that on average every month. A SE wind will blow a F3, only 2% of the month of June.
In contrast the Northerly arrow shows that it will blow a Northerly F4 almost 30% of the time for that area.
The number in the middle, in this case 2, represents the % of calms. So in this case, you wouldn’t be expecting a flat calm very much. In fact you would be expecting wind of F3 to F4, 98% of the time.
Ideal! Can’t wait till I’m sailing down there on the 20th! Touch wood!
Small note. The Wind Roses aren’t always as favourable as this one. Hence their importance when planning!
There is a lot more to learn about these very important charts. There’s Wave Heights, Great Circle routes, Tropical Cyclones, Ocean Currents….
Please follow our blog for the next installment!