Day 87 – Log Working
Where Next?
Bob Williams
Thu 10 Mar 2022 16:09
Course: ESE Speed: 5 knots
Wind: WNW, F4 Sea: slight
Swell: WSW 2 m Current: W 1 – 1½ knots
Weather: broken cloud, mild
Day’s Run: 99 nm
Today’s little victory is that I have managed to get the electronic log/echo sounder working. Alleluia!
Yesterday I noticed that the unit came on when its little solar panel was in sunshine even when its internal battery was not connected so I figured if I can provide a permanent power supply from Sylph’s batteries via this circuit then I wouldn’t need the internal batteries. Fortunately I have a small DC-DC converter with a variable voltage output on board. Also fortunately the wires leading from the unit’s self-contained solar panel were reasonably accessible. It took quite a bit of fiddly work but I managed to snip those wires, solder some longer wires to the circuit board side, then connect that to the DC-DC converter set to three volts and, hey presto, it all works. So I have now screwed it back into place on the forward cockpit bulkhead and have a functional log again.
One of the motivations in wanting to get the electronic log working again is that yesterday when I worked out the daily run using the figures from the Walker trailing log I came up with a run of 176 miles. I thought that can’t be right and took yesterday’s run based on the GPS’s figures (normally I always compare the two figures to see if we might have any significant current running). Well, overnight, as usual, I was monitoring Sylph’s progress glancing up at the GPS readout on a regular basis and noticed that Sylph’s speed seemed quite a bit less than I would have expected for the feel and sound of her movement through the water. I started to suspect that we might have some current against us. While I now have the electronic log working, unfortunately I still need to calibrate it. Until I can do that I have applied a correction based on my intuition and it seems to corroborate the idea that we have about one to two knots of current against us. The other evidence is that the electronic log also provides the water temperature which is at 16.5 degrees, significantly higher than I would have expected for this far south.
Why so much concern with the current? Because the Cape of Good Hope has an infamous reputation for incredible rogue waves, up to 30 meters, hollow and wall sided, when a SW gale comes against the strong SW setting Agulhas current. Naturally I want to steer well clear of any such phenomenon. The west setting current this far south is likely due to one of the Natal pulses I mentioned earlier. Not to worry. I have a few days to work our way a bit further south and also given the rotational nature of these pulses there is a good chance we will clear it just by continuing east. I also want to balance this consideration against the fact that the further south we go the more intense the lows will be and the stronger the winds, and as mentioned yesterday, an intense low is expected to be rounding the Cape in a couple of days at the same time as us.
Still, I feel like Po-han in Richard McKenna’s wonderful novel “The Sand Pebbles’, about an obsolete US Navy gunboat, the ‘San Pueblo’, based in China between the World Wars (I think). Po-han is a Chinese coolie who unofficially works on the ship as the engineer’s assistant. Holman, the NCO engineer, and Po-han spend all day trying to remove a flywheel from the old engine and only manage to get two nuts off.
“By suppertime they had loosened one more nut. “Ain’t much, for a day’s work.” Holman said wearily. Po-han grinned. He was happy about that second nut.”
And I’m pretty happy about getting my electronic log working.
All is well.