Ah, the Trade Winds
Mar 22 2012
The well known “steady and powerful Trade Winds” that have driven oceanic commercie since the first mariners headed out across the Atlantic. These winds rise out of a band just above the Tropic lines (Cancer and Capricorn), driven by high pressure cells. These cells, the very same that create the stil air centers of the Gyres we spend so much time create massive columns of descending air that first rose from the equatorial sea surface. As it decsceds and moves out from about 30-35 degrees latitude (California level) it moves out laterally along the sea in a SW direction. That is what is supposed to be powering Sea Dragon as we speak. You can see them below a the streams of wind arrows moving East to west along the team’s course track.
That is the good theory…. however that high pressure cell changes shape, strength and location. So the Trades while wonderful for sailing are neither steady or entirely predictable. Looks like they are very light now and soon to be really, really quiet. You can read the speed in the arrows. Each long feather on the arrow shank is 10 kts, a short one is 5 kts. 15 kts may sound like a lot, but when its running with a boat going 8kts, you will only feel about 7kts – not much air to move a boat. Sea Dragon is just about 135 Longitude on this picture. Stay tuned!