ELECTRONIC CARTOGRAPHY

A large majority of boats navigate using electronic charting software. Most of this software comes from data from the Hydrographic and Oceanographic Service of the Navy (SHOM).

More commonly called “chart plotters” or “chart readers”, they can be combined with radar, AIS… and it is rather useful to be able to compile on a single screen a maximum of information usable in the instant.

Prices vary depending on the types of devices and functions requested. It is a significant investment, especially with the purchase of dedicated cards which are often not provided.

However, there are advantages and disadvantages to using this software, which will affect your browsing habits.

BENEFITS

Generally, the yachtsman finds his account by the ease of use as well as the improvement of the identification and the safety which results from it.

The navigator can easily locate his boat instantly, delimit one or more areas to avoid, determine his route in complete safety while spending a limited stay at the chart table. It’s quite comfortable to have this type of alarm especially if he is prone to seasickness 😉

It is also possible for him to be able to navigate with an extremely reduced pilot’s foot during delicate passages with increased safety and great precision.

In some dangerous areas by the presence of rock heads or even coral reefs, the tracer is rather welcome.

Maintaining electronic charts is also easier than it was when using paper charts, greatly reducing the work of the navigator.

In weather routing, whether in coastal, offshore cruising or even racing, it is possible to combine, superimpose weather Grib files, and tidal currents allowing an optimal route choice with regard to the boat’s polars.

But also associate certain devices such as radar, AIS, anemometer, depth sounder and thus gain confidence and avoid any risk of collision with other vessels, especially with a reduced crew.

THE INCONVENIENTS

There is enough to get lost with a difficult choice of electronic cartography using either:

• the Raster map often not updated for navigators in distant lands. These cards are often scanned cards that are less and less used and still present on a number of devices
• the vector map that must be purchased in addition to the devices. After a while, these maps are no longer updated because the software used does not support it. It is therefore necessary to buy cards for complete updates. Namely, that it is the responsibility of the skipper to keep all these official documents up to date.

One of the major drawbacks would be power failure or computer failure. It would obviously no longer be possible to take stock of the map, nor even to continue on its way or to return to port.

There are many operating systems such as the WGS 84 system which, adopted by the vast majority, is still a significant source of error, especially in tropical areas where you can see your boat sailing with an offset of a few hundred meters sometimes.

In addition, the incorrect use of the zoom could, by a scale not adapted to the navigation area, not show you the important details of danger of rock head type or other.

TIPS AND TRICKS

• Check the accuracy of the GPS positioning on your electronic chart by taking a landmark defined as the exact place in your port location or even the entrance, the proximity of a buoy…
• Have redundant electronic cartography on board in case of equipment failure.
• In the event of a general breakdown, it is common sense to have paper charts on board even if the regulations do not require you to do so.
• A portable, battery-powered GPS giving geographic coordinates only. To avoid using up the batteries and damaging the device, put the batteries aside. This is to allow you to plot the points on a paper map.
• Have your offshore option yachting license or have some good navigation skills.
• Take the time to study your instruction manual in view of the wide variety of types of devices that use electronic cartography.