I shall not repeat the rash predictions (Ad Lib 16) which preceded, perhaps precipitated, Stargazer's auto-pilot problems (Ad Lib 17). Instead I shall repeat the words of Bob Marley: "We know where we're going. We know where we're from......" (Exodus 1977)
Following a Friday evening visit, from PTmarine Paul, a glorious green glow once more bathes the darkness of Stargazer's bilge. Emanating from the nine-axis motion sensor, come compass, which informs the pilot's actions.
A poor connection, in the single cable which provides power to and conveys data from the sensor, was the culprit. Quickly identified and corrected, by Paul. Thus restoring Stargazer's second crew member to active service. That is "where we're from."
As to "where we're going:" The movements of the moon mean that the tides are at peak springs. Bringing depth constraints to the Sovereign entrance (Ad Lib 16).
As well as swingeing flow rates, particularly on the French side of the Channel. Where the tide will drift Stargazer two and a half nautical miles sideways for every five she travels forwards. Meaning that we will travel at forty five degrees to the direction in which our bows point.
Simply steering into the tide would halve our speed. Instead, the trick, for a fast crossing, is to find a passage timing during which the East and West going tides (more or less) cancel out. On a day on which wind direction and strength allow us to steer thirty degrees to either side of south.
Picture Credits
‘Admiralty Tidal Streams Atlas: The English Channel’ page courtesy of The United Kingdom Hydrology Office.
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