Light Winds

Where Next?
Bob Williams
Mon 16 Jul 2007 20:53

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 Nantucket Island.  This morning we virtually drifted over Nantucket Shoals and were presented with some interesting displays of turbulence as the tidal currents passed over the shallow irregular bottom.  The fog has come and gone a couple of times, not unusual here as the light southerly breeze laden with warm moist air passes over the upwelling cool northern waters.  At 9 a.m., in respect of some of the water works we were witnessing, it seemed prudent to get clear of the shoals so we motored for 3 ½ hours until we were in deeper water again.  There we set the drifter but even this light wind sail needs something to fill it so after a few more hours of rolling in the short low swell we have dropped even this sail to patiently await even a little wind.  This is a greenhouse gas minimizing voyage.

 

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?