Light Winds
Noon Position: 41 24.0 N 069 43.6 W Course: 060, Speed: 0 knots Wind: ? The last 24 hours have been tiring work. We carried
the breeze until 11 p.m. last night, then it became light and fitful and fog reduced
visibility to 200 yards just as we were encountering a tricky piece of navigation
approaching With the light winds we have only made good 111 miles
in the last 24 hours, an average of 4.6 knots. And why a knot? Well a knot is a measurement of
speed, that is 4.6 knots is 4.6 nautical miles per hour. The term comes from the
way sailing vessels used to measure speed before electronic and other nefarious
aids to navigation were invented. They had a long spool of line with knots
tied at regular intervals along its length and a 1 minute egg timer. They
would stream a piece of wood tied to the end of the line (the log), flip the
timer and count the number of knots that passed over the stern rail as the
timer ran out – a very simple and effective system. Because navigation
used to be so uncertain measuring the ship’s speed was very important as,
away from sight of land, often plotting the ship’s course and speed on
the chart, known as dead reckoning, was the only way the navigator could work
out where he was. Obviously the longer the navigator went without any other
information to confirm the ship’s position the more in error the dead
reckoning would become which could lead to some very anxious times for the ship’s
crew and not infrequently to calamitous and sometimes deadly consequences. To
this day a ship’s log is both the instrument for measuring the ship’s
speed and the book in which this information is meticulously recorded. Are our “Moby Dick” readers following
this? |