November – the sextant survives in the navy, & joy in little jobs

I learnt this month that Royal Navy officers still have to learn and practice astro-navigation with a sextant, despite the incredible array of technology at their disposal.

I was at a Zoom meeting with Rear Admiral Peter Sparkes, the UK National Hydrographer, organised by the Suffolk branch of the Cruising Association.

He gave two reasons for continuing to insist on familiarity with traditional navigation on warship bridges: the first is the risk of damage to electronic systems, which is an obvious one in combat; the second is jamming of GNSS satellite signals.

Sparkes did not go into detail, but satellite jamming is a problem which armed forces everywhere are trying to solve. A variant of jamming is spoofing, where the signals are altered, still giving a position, but a wrong one.

The Rear Admiral said he hoped there would be technical solutions soon to the satellite problem. He did not elaborate, but updated versions of ground radio-based navigation systems such as Loran are certainly being revived.

There is also a big development effort to shrink inertial navigation systems to a more manageable size and greater accuracy using electronic and even quantum forms of gyroscopes, to track position by measuring cumulative changes in direction and speed without any need for outside signals. These could prove vital as satellite backups in a whole range of applications, including driverless cars and ships if they are to operate safely.

An article on quantum gyroscopes in this month’s Royal Institute of Navigation journal points out that commercial airlines have never relied entirely on satellite navigation, and always have backup inertial systems. There’s a lesson for amateur sailors: if the navy still has traditional navigational backups, we should all make sure we have them as well.

Meanwhile, it’s been lockdown again, and the boat is out of reach, four hours drive away from where we are living at the moment. There is compensation, however, in some ordinarily dull winter jobs, which have been peculiarly satisfying this month.

I finished making a new canvas cover for the inflatable dinghy, a much smarter version of the original plastic sheeting that came with it when new. That was disintegrating after 16 seasons strapped on deck in summer sunlight. And at last I found the annoying but minute leak in the dinghy, which had been softening it overnight. I patch repaired it.

Smart new canvas cover
Refurbished Dan Buoy, saving £125 for a new one.

After years struggling with the Dan Buoy because it would not extend to its operational height above water of 2 metres, I also brought it home to repair. Someone had grabbed hold of it and bent the tubing when climbing the stern ladder, and the bends were jamming the telescopic mechanism.

It proved impossible to straighten on the boat but on a workbench, after an hour of fiddling, it was operational again. I also made a new red flag because, like the dinghy cover, the old one had disintegrated in the sun.

Then there were little bits and pieces to buy, including a carbon monoxide alarm. We were prompted to finally get one by yet another RYA warning, after two people had been killed by the leaking exhaust of a diesel boat heater.

I’ve bought a new tin of varnish to take to the boat to smarten up the chart table and the bulkhead behind it. A more important job we’re thinking about is buying and fitting a big electric bilge pump, to replace one of our two manual pumps.

Those are big, and manual pumps were fine with a previous owner’s racing crew of 6 or 8. However, you can’t have most or all of the crew pumping in an emergency when there are only two or three: we should have installed an electric one years ago.

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