11 hours ago
Have you ever seen a map like this? It is called a Pilot Chart, and is our favorite out of all the paper charts on board: it tells you, for each month of the year, the average prevailing wind direction, wind strength and current for any spot in the ocean, based on 100+ years of ships’ logs.
A sailboat cannot sail directly into the wind; the best you can do is dogleg back and forth at a 50-60 degree angle (called “tacking”), which is slow-going and a rough ride. It is far more pleasant to go where the winds will take you, and Pilot Charts are their best predictor more than a week or two out.
You are looking at the April chart for the Gulf of Mexico, Caribbean, and Bahamas. Take a look to the east of Jupiter, FL, at the blue wind rose with what looks like arrows stuck into it. There are eight arrows for each of the eight standard directions (North, South, Southeast, etc.), and the length of the arrow shows the relative percentage with which the wind blows from that point on the compass. Here it appears that the wind almost always blows from the East, Northeast, or Southeast. So if you are trying to go East, as we are, this would not be the ideal place to do it. It’s not a deal breaker, however: westerly winds are infrequent, but do happen in the wake of cold fronts, when the wind clocks around predictably and sometimes creates a window to make easting.
The number of feathers denotes the wind speed / sea state using the Beaufort Scale (1 for dead calm, 12 for a hurricane). Force 4, as shown here, is decent sailing: 11-16 knots of wind and smallish waves, pretty typical conditions in these latitudes. We mustn’t forget, however, that half of the sample size was higher than this average level, and also that ships try to avoid areas where there weather is bad, so there are fewer reports of bad conditions than there would be, were this not the case.