How to choose a chartplotter
There are several considerations that should be taken into account when purchasing a chartplotter. The two biggest considerations are screen size and budget.
Tony Moore of The Binnacle always says "Get the biggest screen that will fit on your boat and in your wallet." Screen size is a factor that will make you realize bigger is really better, but it is also the factor that most affects the price of the unit.
Chartplotter screen sizes typically range from 5" to 12" diagonal so you can see how screen size is the first question you should consider before you shop for a chartplotter. But keep in mind you do not need to break your budget to get a high resolution display with good detail in a smaller screen unit.
Like many flat screen televisions, chartplotters may include features such as touch-screens, WiFi, Bluetooth and Smart Phone apps. Consider whether these features are important to you by thinking about how you will actually use the unit. Will it be primarily used as a fishfinder? Will you want to display other data on it such as radar, audio, or entertainment? Do you plan to integrate other instruments with it?
Other things to consider when selecting a plotter are connectivity and compatibility to other marine electronics. You want to determine if your plotter is able to connect with other components such as your VHF radio, autopilot system, radar and AIS via NMEA2000 or NMEA0183?
Chartplotters perform three main functions.
- Straight line navigation. This is waypoint navigation, where the user inserts a destination point that can be defined as the positions Lat & Long coordinates. The device will then provide the following information: bearing, speed, and heading to waypoint. The bearing provides the direction to follow, the GPS speed of the vessel provides the estimated time of arrival to the destination while the heading provides the current vessel's direction, which is also helpful in order to make navigation corrections.
- Tracks - the waypoints recording function. It is important, for instance, in narrow waterway navigation, in order to avoid obstructions such as rocks, or to execute reverse route navigation back to the starting point.
- Routes - the boater inserts a collection of waypoints, similar to the function provided in other navigation devices. The chartplotter will provide directions from one point to the other.
Charts - All chartplotters come with a base map but that's not enough detail for navigation so you will require a chart card. Some chartplotters include navigational charts and others require you to purchase a chart card. You will have to know the chart cards used by the brand/model of chartplotter you purchase. The popular brands of chart cards are
Most chart cards include much more geographic area than you will ever use.