37:36.3N 45:27.6W

Paddy Smyth contributes today’s entry...

The day’s run was 105 miles. We have a gentle 12 knots of wind from the SW and feel that we are now correctly placed on the edge of the Azores high pressure system. This is a comfortable point of sailing with minimal rolling. We’ve had a much-needed chance to catch up on sleep.

Today has been glorious sailing, with the spinnaker hoisted in warm sunshine. We are heading where we want to go, rather than zig-zagging as we did when the wind was directly behind us.

Two of us, Allan and I, are practising some astro-navigation during the voyage. What is the point of that you may wonder, when we have a main GPS and a backup which can give a position to within 10 metres. The prospect of both systems failing must be very low. Even then, we could safely press on until reaching Europe – or Africa.

Firstly there’s the intellectual pleasure – you need to understand how the heavens move and visualise an enormous triangle, with the corners being the North Pole, the point directly under the sun, and one of us with the sextant. The maths is quite easy, simply a matter of adding and subtracting angles. The exact time is critical and we have the benefit of a digital stopwatch set to GMT.

Then there’s the history – the same principle has been used for years though the mathematics has got easier. We are using a book of ready done calculations that was designed for quick and easy use in aircraft 70 years ago. After looking up the details of the sun’s position at the exact moment of the fix, we can produce an answer in five minutes. But then, think for a moment, how were those countless calculations done all those years ago? And consider the printing process of pages of small numbers in the days before computers.

Eventually, when you plot the answer on the chart, you have the satisfaction of knowing that we are truly crossing the ocean, because you have measured it yourself.

And finally, it’s more satisfying than Sudoku, and not only because there is a point to the deliberations but the result is actually useful!