Knowing where you are and how to get to where you need to be is a quintessential skill. Marine navigation used to require you to determine a position and plot it on a paper chart. Things have changed over the last few years and the digital revolution and has brought about some positive changes to the way we navigate our boats today.

Paper charts

The traditional way of navigating a sailboat, paper charts have many advantages: they’re easy to obtain, work without electricity, and once you learn a few techniques of plotting a position and a course, they can be quite easy to work with. Here’s a video giving a basic introduction to marine charts.Their biggest practical disadvantage is their need for a neat surface, preferably dry, flat and steady. Imagine you’re looking for a sheltered harbor entrance in the middle of the night in strong winds – having to go down below, plot your position and determine a course to steer can be a daunting task. Plotting a course on paper also means you have to manually convert between compass, magnetic and true courses, which is error prone (we’ll cover that in a later issue).

Another disadvantage is their need to be manually updated, at least once a year. Updates are issued in “Notices to Mariner” announcements and describe what’s changed since the chart was printed. Updating them can be an involved and lengthy process as this video shows.Where can you buy them? You can buy charts at a local chandler, who will have a selection for the surrounding area. Otherwise you can buy them online (from Imray for example) or if you’re happy with a set of used charts, eBay is worth a look.

Navigation using smartphones and tablets

Somewhere in the middle between the accessibility of paper and the feature richness of chartplotters are a rage of navigation apps for iOS or Android. These provide an easy to use interface, and often feature very accurate and up-to-date charts. There are plenty to choose from, we use iSailor, we’ve heard good things about Navionics as well. Here’s a review of some of the tablet apps available.

These apps use your phone or tablet’s GPS sensor to determine your position. From there you can plot a course, set waypoints, look up navigational marks and investigate other chart features. If you’re planning to use a tablet for navigation, make sure it has a GPS sensor. Some tablets use the cellular network to determine an approximate position, which doesn’t work when you’re offshore and out of range. The only downside we can think of is that these apps lack some of the more advanced features of chartplotters, such as radar and AIS overlays for instance. Another disadvantage compared to paper charts is that tablets and smartphones need power, so you need to think about how to charge those gadgets while on the go.

Chartplotters – The ultimate navigation tool

Chartplotters are small, integrated and dedicated-to-the-task computers that can be installed on your boat. They come in different ranges, starting with entry level “fish finders” (that don’t do much other than display your position on a chart) to more advanced models that can integrate with systems on your boat and overlay the information. Often too they come with integrated GPS so there’s no need to connect them to your vessel’s GPS. Marine charts come pre-installed, so you don’t need to worry where to get the charts from. They can also be a pain to update, this article explains how to approach it.

They can be either installed below at the chart table, or, even more useful, directly at the helm. Having the chartplotter at the helm has a huge advantage: you’re most likely to need your chartplotters help when you are in a gnarly situation, and having the instrument right at the helm gives you crucial navigational information when you need it most. They are of course expensive, which is the major disadvantage. Some of these devices have also gotten bloated and complex, so that learning how to use this tool becomes a challenge in itself.Chartplotters: which is best for my boat?

So what’s our verdict?

For us, having paper charts as a backup is a must. When cruising in local waters along the coast, we mostly rely on our smartphones. We use iSailor, and have found it very stable and useful. Having said that, on our Fastnet boat we have a chartplotter at the helm and at the nav station. It has been proven incredibly useful when out in the night, tired and wet.

Need help deciding, pad vs plotter? This article might help.


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