For a navigator on a yacht as much as on a ship, the advantages of knowing instantly where you are on a chart, and where you are going, are too obvious to dwell on. An old-time merchant navy officer would have spent many hours in junior officer days correcting paper charts. Tony, the retired master mariner with whom we share our boat, had to do exactly that in his early days. Electronics were therefore the answer to a mariner’s prayer: hundreds, indeed thousands, of charts on one machine, with corrections of the whole portfolio available in one simple operation over the internet. Yet even recently there have been published accounts of yacht cruises round Britain urging people to buy full portfolios of paper charts.

For our own round Britain cruising (the second time in the last six years), £3000 would buy fewer than 130 new UKHO charts, compared with the 850 which Memory Map says it incorporates in its UK and Ireland package. Even with a limited paper edition, we would never have a hope of keeping them all up to date unless we devoted weeks in the winter to correcting. If we bought second hand, even if we could find them all, the correction effort would be much greater.  

In contrast, the Memory Map charts on the laptop cost only £50 for the UK 2013 edition, which includes every chart for the British Isles.  Our c-Map charts for NW Europe, including the whole of the British Isles, cost £180 new and just over £100 a time to update, which can be done several times a year, rather more frequently than most sailors I know get round to updating far smaller paper chart portfolios in practice. Navionics on the iPhone (and shortly on a tablet) is even cheaper, and updates automatically.

The result is that for both round Britain cruises we have bought mainly small scale Imray paper charts and very few large scale UKHO ones. We do not yet rely primarily on electronic charts, because we do not have robust enough electrical and electronic backup systems; but in practice, partly for budget and partly because of the ease of correction, we’ve tipped the balance quite a long way away from reliance on paper. Judging by conversations with other leisure sailors, that is rapidly becoming the norm.

So what exactly is it that makes it safe for a modern 100,000 ton ship to go entirely electronic, when yachts are faced with warnings on their chart plotters and electronic charts that they should not be used for primary navigation? The C-Map licence, for example, says “Only up to date official government charts and notices to mariners contain all information needed for the safety of navigation…..Unless otherwise specified by national maritime authorities, the data licensed hereunder is inadequate as a primary means of navigation, and should be used only as a supplement to official government charts and traditional navigation methods.”

The key official conditions for dispensing with paper charts in the commercial world are:

·  The ship must have an Electronic Chart Display and Information System (ECDIS) approved and certified by its flag state, backed up by a second fully independent ECDIS system. For many ships, an ECDIS system is now mandatory, and it will soon be for all. (The “improved positional awareness”, as some professionals put it, far outweighs the risks of going electronic). Ships may back up an ECDIS with paper charts, but a second ECDIS system has the attraction of avoiding the confusion that can arise from trying to keep paper and electronic portfolios simultaneously up to date.

To go paperless, both systems must use  vector electronic charts, not raster electronic charts (which are basically facsimiles of paper charts); the vector charts must be government issued or authorised and reach a very high level of specification and be updated frequently. One of the many mandatory functions is to display chart quality information, an amplified version of the source data diagrams on UKHO charts. Charts sold with the “professional” label for smaller commercial craft and fishing boats do not meet this standard, and neither do leisure charts.

·Navigators must be trained to a high level in the use of the systems.

Superyachts may be able to afford all that today. But is it possible to get close to these strict conditions on a modest-sized cruising yacht?

Next article: ‘how to mimic big ships’