Pilot Charts

Sunday Afternoon, June 27, 2021
Latitude 43o 28’ N
Longitude 55o 21’ W
(1917 nautical miles to Fastnet Light, Ireland)

Pilot Charts

The choice of the route and timing of our trip across the North Atlantic is not arbitrary. We are sailing based on the hard-won experience of sailors from hundreds, perhaps thousands of years ago. Somewhere ages ago a sailor was setting out to sea and a fellow mariner who’d been there before him generously shared his knowledge of the winds and currents. The advice might have included the best time to avoid storms and the best path to take. For the North Atlantic, this experience evolved into the triangular trade routes that went from the Americas, over to Europe, down to Africa, then back to the Caribbean … thus the planned route for the Lillian B to get back to Rockport Maine.

A historian might be able to tell you how this knowledge was recorded and passed on from sailor to sailor, generation to generation. Today these data from centuries of observations can be found in published Pilot Charts. These charts provide a wealth of information for each month of the year, including ocean currents, the average distribution of the direction and magnitude of the wind, water temperatures, air temperatures, and wave heights. For July, the charts include a dotted line indicating the mean maximum iceberg limit for ice sweep southward by the Labrador current, with dated triangles marking exceptions to this average, such as the iceberg that sank the Titanic.

For July the Pilot Charts states, “The frequency of gales (winds over 35 knots) is at a minimum in July,” and so is the probability of waves larger than 12 feet. And the winds and currents are in our favor going east from North America. According to an intrepid Viking from long ago, this is the best time to cross.