At Sea, Approaching the Gambia
Today we spent the entire day at sea, making our way from Sierra Leone to the Gambia. It was a day filled with changes in the sea and in our general environment. Early in the day we were sailing through smooth water where we saw a number of Portuguese man-of-war siphonophores floating on the surface.
As we turned north along the western coast of the great bulge of northwest Africa we soon encountered the Canary Current flowing against us at about one knot. The wind began to blow out of the north, as is the prevailing wind in this area, producing a very dynamic coastal upwelling system which results in abundant fisheries. This production makes this area the most heavily fished place in the entire world ocean, with ships from all the fishing nations of the world working up and down this coast.
The wind also stirs up dust from the nearby Sahara Desert which produces a haze over the ocean, but which also diffracts the signals from VHF radios. This produces much longer ranges for both radios and the Vessel Automated Identification System which all ships are supposed to carry these days. This long range allowed us to identify ships as far as 500nm away and to hear radio transmissions from hundreds of miles away in a great variety of languages from the numerous fishing vessels which ply these waters. We spent a very interesting day on the bridge trying to identify all the different languages coming in on the radios.
This was also the day when we passed the sun on its and our journey north. The sun today stands above a latitude of 11º 34’N and we passed that parallel at about 8:00 p.m. this evening, so we are now farther north than the sun for the first time in many months.
