Relearning old navigation lessons

Two letters in the latest issue of the excellent Cruising Association magazine* claim it is now safe to rely entirely on electronic charts because backups to the boat’s main chartplotter are so cheaply available. You can leave your old paper charts abandoned in the bottom of a locker somewhere, the argument goes.

However, while researching updates for the yachtmaster book I mentioned last month, I’ve been re-reading intensively about old fashioned navigation techniques I learnt a long time ago, some of which were beginning to fade from memory. It has reinforced for me how important it is to avoid total reliance on electronics and have a portfolio of navigation skills including the old ones.

Traditional chart table at the end of a sail home from Scotland, and the bottle we brought back to celebrate our return .

So I think discussion of electronic charts needs to be a lot more nuanced than some of their more enthusiastic users suggest. Yes, on Spring Fever we have also relied heavily on electronics for many years, but my worry is how easy it is for phone, tablet and laptop software as well as hardware to fail, which can take a long time for the less than totally expert to sort out on passage.

It is certainly true that most well equipped offshore boats will have one or more extra chartplotters loaded on tablets, phones and laptops. Some are backups in case the main plotter system run from the boats batteries fails – that only takes a bust alternator or an engine that refuses to start. I also hear that an increasing number of people are dispensing with dedicated marine chartplotters altogether and relying on tablets etc.

Two examples of what can go wrong: my tablet’s GPS receiver failed last year. After a great deal of googling back home I found out why – I had not updated it for the GPS clock change that took place last year (little noticed, but the navigation equivalent of the millennium bug in 2000). Updated this winter using wifi at home, the GPS started working again, ready for this season. Hands up all those who knew about this and fixed it in advance. My problem was an older tablet. Recent ones would have updated for it automatically.

This was specifically a US GPS problem, and I don’t think it affected the wider GNSS, which includes the Russian, European and Chinese satellites processed by newer receivers than the one in my tablet.

More seriously, my laptop had earlier ground almost to a halt because of some unknown and untraceable software issue picked up I know not where – probably not a virus, or at least not one my Norton protection could find. I abandoned it for navigational backup and planning in favour of the tablet, well before that too showed it could let us down.

This winter, having bought a new laptop, I did a factory reset on the old one, wiping everything except the Windows 7 operating system. Miraculously, it now works like new. So I have loaded the charts, GPS driver and related software again and it is going back on the boat and staying there. I will keep it bug free by not connecting to the internet.

The laptop will be used for planning, with the cockpit chartplotter still our main instrument. But the laptop is old and has a hard disk drive rather than a solid state one, so can mechanically wear out. We may add a further backup in the shape of a small, cheap 7 inch tablet from visitmyharbour.com that’s tough and cockpit proof. (£170 loaded with 2020 raster charts for the UK, France and Atlantic Spain and Portugal).

Computer hotshots might have done fault-finding at sea or in a marina but it took me a whole day at my desk to figure out the laptop solution and sort it, using a high speed internet connection. The software fault had even disabled the DVD drive, which is now working again.

This is not the end of the list of issues. Tablet and phone navigation relies on apps and they do sometimes misbehave. Often the solution is to uninstall and download again – not an option for us at sea. That problem cropped up last year not with a chartplotter app but with one of the best tide prediction apps, though it could easily have been one of the chart apps. This all tells me – a reasonably capable but far from expert user – that the issue of electronics reliability, even with multiple backups, is complicated.

And that is without more basic questions, the first of which, GNSS reliability, I have covered in two previous posts. (On that subject, I have just read a report that GPS spoofing equipment can now be bought for only $100, and how to use it is widely discussed on line).

There is of course the more widely considered question of what happens to your backup tablets, phones and laptops in a knock down, a partial flooding of the saloon, a fire that you may put out but which causes damage or – a nightmare – a lightning strike.

I’ve had a strike on a previous boat, while it was moored on a river – I was ashore – and it destroyed all the electronics and made for a large insurance claim. High voltages nearby can induce large currents in equipment even if it is not wired into the boat’s own circuits. The advice I hear to stick your laptop, tablet and phone in the oven to shield them if lightning is near I find the complete opposite of reassuring!

So we don’t plan to chuck the paper charts, dividers, almanac and ruler in the bottom of a locker somewhere – they’ll always stay ready in the chart table, and we’ll use them from time to time so as not to forget how.

By way of contrast: now reading this 1987 book, which makes even our traditional navigation seem hi-tech. It’s about the last island outposts of Pacific Ocean navigation skills going back thousands of years, which use only knowledge of stars, waves and birds, and no instruments, achieving remarkable accuracy.

* Cruising, Spring issue.

February – averting satellite disaster

The British government turns out to have been ahead of the game on the  satellite risks I mentioned last month, with a £36 million programme just announced to  prevent navigational satellite failures damaging the economy by as much as £1 billion a day. It is feared that the entire country has become over-dependent on a handful of satellite systems.

Emergency services, the energy grid, mobile phones, Satnav, broadcasting and other communications, the Stock Exchange and an array of other activities all rely heavily on the super-accurate timing provided now by navigational satellites such as GPS and similar systems. There are life-threatening risks from failure, says the government.An image of a third generation Lockheed Martin GPS satellite

The new investment is in a National Timing Centre to create a network of super-accurate atomic clocks around the UK, accessed through ground-based communications, so that the economy will no longer be over-reliant on timing from GNSS signals from the sky.

GNSS is the term that embraces the US  GPS, the first system, Russia’s GLONASS satellites, Europe’s new Galileo and also a rapidly developing Chinese system.

Galileo failed completely for a while last year during its start up phase, because of operator errors, and there are now many examples of interference with GNSS systems and malicious ‘spoofing’, in which navigation instruments are fooled into thinking they are somewhere else. The heart of all navigation by satellite is accurate timing, without which positions cannot be fixed.

The Business Department said the centre will provide additional resilience against the country’s reliance on accurate timing, which underpins many every day technologies.  “ If there were a large-scale failure, economic impact to the UK would be £1 billion a day”, the department said. “Loss of this accurate data would have severe and life-threatening effects, such as on getting ambulances to patients or getting power to homes around the country”.


The plan puts the UK ahead of the US, where the issue has been rumbling on since President Bush announced a new satellite resilience plan, and a law to authorise it was passed. Those early moves have not actually produced any results.

President Trump’s White House has just announced a new programme but it appears to be no more than studies for future investment rather than actual projects, according to the Resilient Navigation and Timing Foundation (RNTF), a Washington group campaigning on the issue. The Foundation said the UK plan was a great initiative.

Almost nostalgically for small boat navigators with pre-satnav experience, the UK still operates a ground-based Loran navigation system, though receivers for yachts are no longer available (as far as I know). The RNTF believes that Loran may be expanded and incorporated in the UK timing resilience network, which it thinks will be wireless-based rather than land lines.

Amazing to think how dependent we are on one technology at the moment. Ten years ago we used to worry that the US might degrade the accuracy of GPS or switch it off in a war. That is now inconceivable, so dependent is the entire US economy on it at the moment.

More realistic dangers  include accidental  system failures, as with Galileo, deliberate or accidental interference on a regional or local level, and spoofing. If you think about what some idiot can do with a drone near an airport, imagine the chaos if disruptive forces started jamming and spoofing GNSS. The expertise to do that has been nakedly displayed in recent years in the Gulf and the Black Sea near Ukraine.

Back to earth: as I mentioned in an earlier post, plans are always tentative at this time of year, and so that is proving. The passage to north-west Spain I was writing about in December and January has run into the problem of coordinating two lots of family diaries, which can be tricky with joint ownership and joint sailing plans.

Various unmissable events on both sides now mean shorter periods on the boat this year, so the plans are evolving. Maybe we will go back
to south Brittany, where we spent three seasons recently.  Spring Fever on the River Vilaine, southern Brittany

We could always go down from there to Spain next year. There are so many lovely places on the French coast that it would be no hardship if that is what we decide.

Boat maintenance has been brought back home for me this month, with various canvas repair jobs to do on the safety equipment, sail cover and dinghy cover, plus rope whipping, and also ordering new lifelines and jackstays.

Got a great new  sewing  awl for canvas that is much quicker than a needle and palm..

January – satellite scares, and getting ready for Biscay

At the Royal Institute of Navigation’s small boat conference in Lymington earlier this month, I learnt a lot about  new risks of error  in satellite navigation : I did not know, for example, that it is possible with quite cheap local equipment to fool the GPS on a plane, ship or even a missile into thinking it is somewhere other than its real position.

There are now tens of thousands of reported incidents of errors, deliberate, accidental or of unknown cause, with a substantial number of them unsurprisingly in sensitive areas such as the Gulf, and the Black Sea near Ukraine, suspected to be hostile activity.

Reports of accidental errors include a couple of local failures when US naval vessels arrived in the port of San Diego, apparently forgetting to switch off unspecified electronic equipment, which interfered with satellite-derived positions for miles around.

These are serious issue in defence circles, and of course for boats and ships of any kind near a source of interference or one of the ‘spoofing’ attacks. It is easy to imagine some disruptive force deciding to get hold of the equipment and blocking position-finding in a sensitive commercial area such as near an airport or in a vital shipping lane.

Satellite positions are integral to the operation of every form of commerce, from planes and ships  through mobile phone masts and everyday driving, Amazon deliveries and Uber – you name it and somewhere in the business location finding is vital. So there is increasing pressure to redevelop  an old ground-based system called Loran as backup. Loran has not been switched off, but would now need a lot of development and investment. If you want to know more, look at the website of the Washington-based Resilient Navigation and Timing Foundation.

GPS is just one of five satellite position-finding systems in operation, all now called GNSS (Global Navigation Satellite System). GPS, like the word hoover, is a US name that is in danger of wrongly becoming the label for  a whole range of products.

Other GNSS now running include the Russian GLONASS and the EU’s GALILEO – so in one sense there’s a lot better backup against total failure. GALILEO was completely out of operation for a while last year after operational mistakes were made by its staff. It was only in the start-up phase but the fault  proved that a single system can go down.

The cover of the current 5th edition of Pass Your Yachtmaster

I was at the conference because I have been commissioned to update an excellent sailing book, David Fairhall’s Pass Your Yachtmaster, illustrated with hilarious cartoons by the late Mike Peyton.

Completely coincidentally, the cover of the current edition has a nice but anonymous photo of a Sigma 362, the same model as Spring Fever. Having done 11 seasons polishing and antifouling, I recognise the detail of that bow!

David has updated previous editions of the book, first published in 1982, but asked me to take the baton for the next.  The book is a primer for students doing the Royal Yachting Association yachtmaster exams and tests.

I have to say that re-reading  David’s book and many others on navigation has reminded me of several things I ought to remember, and certainly knew when I did the exam and practical test in the 1980s, but had forgotten, so it’s a good exercise for more than one reason.

Back at the yard, plans for sailing to Spain are firming up so we’re making a couple of small improvements to the boat and some minor repairs. We’ve also booked for the Cruising Association’s Biscay Day in London in March where we will meet others sailing that way.

One annoying issue on Spring Fever has always been the need to lift the anchor from the bow roller a couple of feet along the side of the boat when retrieving it to stow in its locker. I’m always afraid that this is going  to damage someone’s back, holding a 15 kilo weight plus chain at a very awkward angle on a potentially rolling boat.

The reason is that the drum of the Furlex reefing gear almost touches the deck, a feature from the boat’s racing days to maximise sail area, so it blocks the anchor from being lifted straight from the bow roller. We are looking for a rigger willing to shorten the forestay with the mast up, to lift the drum 8 inches so the anchor can be pulled up through the roller, and if necessary lashed and dealt with later. Our usual rigger is not keen because he works alone and it needs two experienced  people, he says.

The sail luff can be shortened at the head because it is very narrow there. Our sailmaker is taking 9 inches off but we will lose only about a square foot of sail area.

We’ve also decided to install a holding tank, so the lavatory can be used when we’re somewhere, er, sensitive to such things eg a marina or swimming bay. Nobody ever asks in the UK or France but Spanish authorities are thought to be more vigilant in checking that boats have holding tanks to store their waste on board, an EU requirement. Very few places have pump out facilities to empty tanks so the usual procedure is to empty them by opening the discharge valves a few miles out to sea.

Spring Fever is ashore this winter at Kingston, the Cowes Harbour Commission yard, rather than at Cowes Yacht Haven, whose prices have been creeping up by the addition of extras. The Haven also focuses on expensive racing boats whereas the Kingston yard, which is very friendly, is mainly full of older boats like ours, so we immediately felt more at home. It is not as conveniently sited, but it is looking like a good switch.

Compasses and sextants obsolete?

  I like this passage in the latest book by Daniel C Dennett, a celebrated philosopher and writer about cognitive science who specialises in the evolution of the mind:

“Already it would be criminally negligent for me to embark with passengers on a transatlantic sailboat cruise without equipping the boat with several GPS systems. Celestial navigation by sextant, compass, chronometer, and Nautical Almanac is as quaint a vestige of obsolete competence as sharpening a scythe or driving a team of oxen. Those who delight in such skills can indulge in them, using the internet to find one another, and we celestial navigators can prudently bring our old-fashioned gear along, and practice with it, on the off chance that we will need a backup system. But we have no right to jeopardise our lives by shunning the available high-tech gadgets”.

He is giving modern navigation as an example of technologies so far superior to anything humans can do that they “usurp our authority as experts”. There are very good practical and moral reasons for giving way to them. 

Good sense, though not sure it will get into the yachtmaster syllabus.
Daniel C Dennett: From bacteria to Bach and back. Allen Lane 2017. Also the source of the quote in the previous post. He must be a sailor!

Marine survey accuracy

Data published by the International Hydrographic Organisation shows up a surprising fact: the UK and Ireland are below Turkey in the league table of survey quality by area of national waters. Spain, Portugal and France score much higher than the UK.

  

Source : selected countries  from an International Hydrographic Organisation table.

 % of area at depths from zero to 200 metres which has been adequately surveyed

% which requires re-survey at larger scale or to modern standards

% which has never been systematically surveyed

Mediterranean

 

 

 

Monaco

100

0

0

Spain

97

3

0

France

95

4

1

Gibraltar

95

5

0

Turkey

88

12

0

Slovenia

80

20

0

Italy

70

25

5

Croatia

39

39

22

Greece

35

55

10

Morocco

30

0

70

Albania

25

45

30

Serbia Montenegro

0

100

0

Cyprus

0

100

0

 

Atlantic, NW Europe 

 

 

 

 

 

 

 

Portugal

100

0

0

Faeroes

100

0

0

Belgium

100

0

0

Germany, N Sea

96

4

0

Denmark

95

5

0

Canaries

95

5

0

Spain

94

6

0

France (Channel, North Sea)

89

0

11

France Atlantic

81

0

19

Norway

60

31

9

Azores

60

40

0

Netherlands

55

35

10

Iceland

52

48

0

UK

49

22

29

Ireland

26

74

0

 Greenland

25

25

50

Svalbard

10

1

89

Jan Mayen

0

0

100

 

Baltic

 

 

 

Germany

98

2

0

Finland

44

49

7

Poland

40

60

0

Sweden

25

74

1

Lithuania

16

84

0

Estonia

13

87

0

 

 

 

Checked January 2013

 There is one obvious reason why the UK’s position is relatively low; with a much larger area of shallow continental shelf, the British Isles has proportionately a far bigger survey to do than a country such as Turkey, where depths in many places reach 200 metres relatively close to shore.

Even so, it is widely known that there are cruising areas off the Turkish coast where chart accuracy is poor. Rod Heikell’s pilot warns that they can be out be by up to 2 minutes of longitude, considerably more than the warnings for anywhere on the British and Irish coasts.

 UKHO chart Q 6090 looks more deeply into the situation in the UK and Northern Ireland. It colour codes areas of the seabed by survey quality.  In the January 2013 edition, large parts of the coast of the Scottish mainland, Hebrides and northern islands, Wales, the Channel Islands, Lancashire and Northern Ireland are still marked as surveyed by leadline, or unsurveyed.

Follow this link to see UKHO chart Q6090

In an earlier 2006 version published in the AIB report on the Octopus (see Orkney Roulette page), the entire coast of  Ireland was marked as leadline surveyed. The republic’s coast has been left out of the latest Q6090, but the Irish government has now produced its own version of the chart, which shows a very large surveying effort since 2006.

Link to Ireland survey coverage chart

Interactive chart with local detail of Irish surveys

One result of the new surveys is that there have been new editions of 22 of the 60 or so admiralty charts for Irish waters since 2009, according to the Irish Cruising Club.

For practical decisions during a cruise, we have to rely on what electronic and paper chart publishers tell us about the underlying quality of their products, backed up, of course, by pilot book advice. This information can be pretty patchy. For example:

  • UKHO charts   have source data chartlets, a benchmark for quality.
  • Imray charts have no source data.  Some Imray charts do have general warnings on chart accuracy, eg for the Ionian and Turkey, where recent editions have quantified errors in the area as up to one minute and half a minute of longitude respectively.
  • Pilot books vary on the issue: Heikell has general warnings in his introductions of much larger errors in Greece and Turkey, of 1.5 minutes and 2 minutes longitude maximum respectively, but that covers a vast area.    
  • The Irish Cruising Club pilot’s latest edition for the West and South coasts of Ireland has gone much further, with localised chart accuracy information for different chapters, a good benchmark to aim for.  
  • Some other pilot books I have checked recently  do not seem to mention the accuracy issue at all, even where they cover cruising grounds which the tables above show have known  chart quality issues (for example parts of the Adriatic).
  • Many leisure electronic charts lack information on source data or other indications of underlying survey quality. They also lack last correction dates, and there is no detail of how comprehensive the updating is. Memory Map does reproduce source data diagrams on its raster charts but not edition dates, even though it is not hard to find UKHO charts for sale now whose most recent edition was three decades ago, for example on the West of Ireland.
  • To find comprehensive source information on an electronic  chart, you have to move to those used in Electronic Chart Display and Information Systems on ships, a different world,  where vessels equipped to a high enough standard are now allowed to dispense with paper charts altogether.

In preparation: articles on GPS accuracy and on what makes leisure charts unsafe compared with those used in ECDIS systems.

Med charter disaster?

Since looking into chart accuracy following the Orkney cruise (see previous article) I’ve spent a couple of months in the Mediterranean. It’s much worse there.

I vaguely knew that, but previous sailing in the Mediterranean had been without chartplotters and on the earliest occasions without GPS. More recently, chartplotters seem to be standard on charter boats as well as private yachts. We amused ourselves by doing some checking.

In the Ionian and South West Turkey (but only rarely on a cruise round the Peloponnese) we noted numerous position errors, often a tenth of a mile, and a couple of times as much as a quarter of a mile; there were very noticeable – almost random – variations in the size of position errors, measured by GPS, within the area of a single paper chart, so it was not a simple matter of the datum being wrongly set (which of course we checked, as well as satellite coverage.) The errors were clearly the result of using an accurate GPS on inaccurate paper and electronic charts based on old surveys.

Rod Heikell, the pilot book author, in a  talk at the Cruising Association in London in February 2013, amused the audience with a plot of a yacht track running up the hill behind a Mediterranean town as the boat approached the harbour. That was exactly the kind of anomaly we picked up, in one case in the Ionian with the boat moving down a road on the island we were coasting.

Now none of this is new to old hands in the Mediterranean, with some of whom I have recently discussed it on a Cruising Association forum. Charts based on old leadline surveys can miss underwater dangers and sometimes have large position errors, mainly of longitude.

The advice, of course, is that GPS should always come second to older methods of pilotage, using eyes, handbearing compass, clearing lines and depth sounders, because while the longitude on charts may be wrong, the relative positions within a single area of a chart – for example a bay and harbour – tend to be accurate. The best a chartplotter and GPS can do is get you out of somewhere by using a plot of the track, once you have safely got in by conventional means. The better equipped Med sailors also talk of radar and forward looking echo sounders. Pilot book authors give GPS waypoints they have checked themselves.

However, it is very different for new arrivals in an area, and for holiday charterers it can be positively dangerous. A couple of recent trips were on bareboat charters with a large UK operator. After a series of chartplotter and GPS checks at known chart positions for a week, we found large and variable errors.  But neither the technical staff at base nor a flotilla skipper we spoke to had any idea of the scale of the local chart errors.

When we checked the equipment on arrival at one base in Turkey, we found the plotter showed the boat nearly a quarter of a mile from the marina. The company sent a technician to rebase the chartplotter’s boat icon onto our pontoon in the marina. It was an older type of instrument which we had not come across before, which allowed recalibration. (This was not a datum adjustment, which we also checked). The technician announced that the plotter was now fine.

That night, 15 miles away, the plotter was a tenth of a mile out; for the rest of the cruise, the charted positions within a cruising range of no more than 50 miles fluctuated from zero to a tenth of a mile and in one case approaching a quarter of a mile, simply because the GPS was more accurate than the charts. Back at base at the end of the week, the error was zero, so there was nothing to show the next customer that there was a problem.

The base clearly thought we were imagining it. I got the impression they were not even conscious of Rod Heikell’s pilot book warning of the size of longitude errors in Turkey. Skipper briefing at the base did warn about chartplotters, but it was not specific to the area, and was the kind of routine mention you hear in the UK. Visiting charterers might well assume it meant the relatively modest range of inaccuracy found at home, rarely more than 100 metres.

One lesson is that specific warnings with numbers attached are vital for getting the message across: for example the Imray Ionian chart used to have a general note warning that there were longitude inaccuracies, and I suspect not much notice was taken. A quantified warning was recently added saying the errors could be up to a minute of longitude, which has a much greater impact. Suddenly you realise what you are up against. The errors could be as big as the gaps between some of the islands. In these circumstances, chartplotters are an accident waiting to happen for holiday charterers. It would be safer to switch them off.

Next, how do we find out more about survey accuracy and chart errors?

Orkney Roulette

Not long after a jack-up rig called Octopus ran aground in Stronsay Firth in the Orkneys in 2006, we were feeling our way into a bay at nearby Stronsay. We crept through shoals and reefs relying on chartplotter and echo sounder, in strong winds and bad visibility, confident that our plotter would get us through: after all, we had checked it frequently on our passage up the English and Irish coasts and through the Hebrides, and had been pleasantly surprised never to find the GPS positions more than 50 metres out on the chart.

So confident had we become in our first chartplotter that a few days earlier, in fog rolling off the island of Hoy so thick that the boat’s bow was only just visible, we used it, along with the depth sounder, to find our way at dusk into the harbour of Stromness, which involves a tight turn round a reef at a point where the tide can run at up to 8 knots into Scapa Flow, right across the entrance to the inlet leading to the town.

 

If only we had known more about the quality of the local charts ….. much later, I came across a Marine Accident Investigations Branch report on the grounding of the jack-up rig Octopus, under tow by the tug Harald, which popped up in a web search for something else. (MAIB Report 18 2007).

 

I glanced at the summary and realised we had been playing Russian (or Orkney) roulette in relying so heavily on the charts, chartplotter and GPS while cruising in the Orkneys. The charts on the west side of the islands, where Stromness is located, were fine, because the area had recently been resurveyed. Much of the rest of the Orkneys, including Stronsay and its sound, was a very different matter: it had last been surveyed by leadline in the mid-19th century.

 

The new surveys had reached parts of the north-central Orkneys, in a programme that had been stepped up because of the risks to cruise ships, which were calling in increasing numbers; but by extraordinarily bad luck the survey work had stopped 200 metres north of the uncharted shoal in Stronsay Sound on which the Octopus grounded. It also turned out that local fishermen knew about the danger, but they had not told anyone.

 

UKHO Chart 2250, covering the danger spot, looked modern, but it used leadline surveys overseen in 1843 and 1844 by Commander George Thomas on HMS Mastiff. The skipper of the tug was using Admiralty paper charts, which display a diagram of ‘source data’, showing the age of the underlying surveys; he also had a monochrome electronic vector chart plotter with Seatrack software, of a type “primarily aimed at the leisure market,” according to the report. The plotter would have used the same underlying data as the Admiralty chart.

 

Leisure electronic charts do not give source data, but there was information  on the paper charts about the age and quality of the surveys on which they are based. How many of us actually take it seriously enough?

 

One of the MAIB report’s key conclusions was that shipowners should “emphasise to shipmasters and navigating officers the need to carefully consider source data”.  Since reading the MAIB report, finding out about chart accuracy and survey age have shot up my own list of priorities; if a chart based on an old survey can cause such problems for an experienced local tugmaster, how many yacht skippers also fail to make enough allowances for the age and quality of their charts?

 

Next: It’s much worse in the Med

 


How to mimic big ship equipment

To cut back seriously on paper charts, the greater vulnerability of equipment on a small craft to accidental damage would have to be taken into account, including lightning strikes. For small boats it is already possible to buy, at a price, extremely robust electronic systems, including waterproof laptops that withstand impacts (costing several thousand pounds), and high capacity lithium battery back-up packs;  small back-up generators have also become cheaper in recent years and can be accommodated on many mid-sized cruising yachts.

At a cost, robust weather and shockproof  electronic navigation with reliable backup systems should therefore be quite close to achievable now on a yacht. Even if we fall well short of the rigorous standards of an ECDIS system, we will not be carrying 100,000 tonnes of crude oil or thousands of containers, so perhaps we can be allowed to be rather less tough on the backup specifications. Similarly with training: new courses may be necessary, but perhaps not the 40 hours plus specified for ECDIS for commercial ship deck officers.

 Here is our current navigation equipment list plus a few items we plan to get. We rely on maximising the number of independent systems, including some which can be isolated from the boat’s electrical and aerial systems ie reversing the current fashion for electronics integration. Whether isolated equipment can be protected enough to see us through a lightning strike is a question that we are still thinking about.

We also try where we can to use portable equipment that we have bought for other purposes, keeping down the boat budget, but we draw back from the high costs of top-end equipment such as water and shockproof computers and screens. Others may have very different and perhaps much better ideas – it would be good to hear them, and especially any thoughts on protection against lightning (we had a strike 12 years ago that burnt out some instruments but not all).

This list is for cruising British and nearby waters.

  • Basic cockpit chart plotter using vector charts.
  • A separate large screen chartplotter at the chart table is a good option. But we have stuck with a standard laptop in an easily removable protective mount. The laptop is plugged into the boat’s 12 V system; two advantages over the plotter are that it is programmable and could be very easily switched to a backup external battery specifically designed for it (see below).
  •   iPhone or similar with Navionics or C-Map charts in a waterproof case, kept fully charged.
  •  An old fashioned stand-alone GPS at the chart table, feeding the DSC radio.
  • An AIT system, with its own GPS, displaying ship positions on the cockpit chartplotter, where it is of most use, but with a USB connection to the laptop in case backup is needed.
  • Radar.

Plus in due course:

  • An iPad or Samsung Galaxy 10 inch screen tablet, with full vector charts and navigation software, with a bracket to hold it at the chart table and a 12V charging lead. With a waterproof case, the tablet could also be used in the cockpit in reasonable weather for a few hours at a time, held in a bracket.
  • Two or more 8 amp hour lithium external batteries, kept full charged, capable of recharging the laptop, the phone and the Samsung if the boat’s electrics fail.
  • If laptops with separate screens improve, a screen mounted (removably) on a bulkhead at the chart table and a keyboard on the chart table connected by bluetooth would be an ideal replacement for the current standard laptop. It would have  the programmability and screen size of PCs and the convenience of tablets, while protecting the screen better than a normal laptop.
  • For those with a big enough boat (not us): a generator and electrical control equipment to feed a spare battery to provide a complete standby power system for emergency lights, radio and navigation equipment.

 With this level of backup, is a yacht safe if it leaves most of its paper charts behind (perhaps keeping just a few small scale charts covering a wide area)? Does it matter that it would be ignoring the legal warnings by using leisure charts in practice as the primary means of navigation?

This partly depends on how seriously we take the inadequacies, as C-Map and others describe their own products, of leisure charts, which is a whole new issue for another article.

Next, an example of paper and electronic chart inaccuracy: Orkney roulette