Autopilot failure, diverting to Figueira da Foz

2nd December 2017

We set off after the kids went to sleep intending to sail to Peniche by the middle of the next morning. Conditions were excellent for sailing, with 20-25 knots starting on the quarter then moving behind us with manageable seas. Once we had the sails set, I had a rest in the saloon while Charlotte took the first hour or two. We were scooting along at 8-9 knots with a reef in each of the main and the jib shortly after Charlotte went to bed. I was looking forward to a rapid passage to Peniche and playing with the sails to eek out a little extra speed and learn more about the boat. The autopilot seemed to be over-correcting a little, which threw us beam-on to the wind/seas a couple of times. OK, I thought, not a great problem as the swell was only 1.5m or so, but I’ll keep an eye on what the autopilot is doing. An hour or so later the same thing happened, but didn’t stop, so I put the autopilot on standby while I considered what to do (I thought maybe the problem was with sail balance).

When it is on standby the autopilot display shows our current heading – which was 210 degrees. But when I glanced at the display it seemed to occasionally flicker, then settle on the utterly wrong heading of 55 degrees for a few seconds, before correcting itself. Now, my hand-steering-while-staring-at-the-sails isn’t perfect, but the land was still on my left and the compass still said something like 210 degrees. So, seeing a heading of 55 degrees on the autopilot was surprising. And, explained why the autopilot was over-steering!

I tried resetting it, turning all our navigation electronics off, disconnecting something new we had installed that might have been interfering with the fluxgate compass that gives the autopilot its heading readings, and a few other things. Then, because I was enjoying the sailing conditions so much, I briefly contemplated sailing the remaining 7 hours or so until dawn without the autopilot. Or, as I would have done if further from shore, heaving to and giving the electronics a proper look over. But as we were only two hours away from Figuera da Foz, I was tired already, and we were not in a rush, I turned for there instead.

An hour or so away from Figurera da Foz I woke Charlotte up, and by 3:30 or so we were tied up on the reception pontoon at the marina there.

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