Type
The type defines the general purpose of the device.
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Echo sounder. Echo sounders are devices designed to study water bodies using sonar. The principle of operation of an echo sounder is similar to that of a radar, but it does not use radio waves, but ultrasound. The initial purpose of such devices is the creation of topographic maps of the bottom of a reservoir, the determination of its topography and depth in various places. However, in addition to this, the echo sounder can be used to detect fish, and with good quality of the device and correctly set settings, you can even determine the approximate size of potential prey.
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Chartplotter. A chartplotter can be described as a dedicated GPS navigator designed for marine use and equipped with related additional features. Such functions include, at a minimum, working with sailing directions (detailed maps of water bodies, indicating depths, currents, etc.); in addition, support for meteorological services, additional equipment such as radars or specific navigation sensors, etc. can be provided. Note that the GPS receiver can be either built-in or external; see Chartplotter Specifications for details.
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Sonar chart plotter. Models that combine the capabilities of both types described above in one device. Such devices are the most versatile, however, and cost accordingly.
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...Sonar flasher. A specific type of echo sounder, designed specifically for use in one place, without movement. Initially, such devices were generally developed for fishing from an ice hole in winter — although this is not limited to such fishing — flashers are also used in summer, including in open water when fishing from a boat. Such devices are by definition capable of displaying fish in real time (see "Functions"), however, instead of a traditional screen, a circular indicator is used, thanks to which the user can determine the direction of the detected object. And the features of this object (more precisely, the signal reflected from it) can be determined by the colour of the mark on the indicator: for example, a red mark corresponds to a strong signal, yellow to an average signal, green to a weak one. Another advantage of a flasher over a traditional fish finder is its high sensitivity, which allows you to follow even small baits. Thanks to all this, such devices are quite popular among anglers, however, they are not cheap.Side scan
Availability of the
side scan function in the echo sounder.
Devices with this feature are able to "see" the bottom and underwater objects not only directly under the vessel, but also on the sides of it. Note that different models can differ markedly in the angle of coverage of the side space. However, the side scan anyway expands the capabilities of the echo sounder and provides additional features compared to the usual bottom one.
Digital data processing
The presence of a
digital data processing system (DSP) in the design of the echo sounder.
Digital processing allows you to separate the received signal into extraneous noise and useful data. Of course, such a division is not 100% reliable; however, the level of noise in the filtered signal is still significantly reduced, and the screen receives a maximum of useful information and a minimum of extraneous information. The disadvantage of this function is traditional: echo sounders with DSP are somewhat more expensive than usual ones.
Memory card slot
The presence in the design of the device slot for working with removable memory cards. Some models may have more than one of these slots.
Memory cards are very popular in modern portable electronics due to their lightness, compactness and relatively low cost. In chartplotters, such media can be used both to expand the device's own built-in memory, and to exchange data with other equipment — for example, rewriting tracks on a laptop or downloading updated navigation maps from it (see below). However, it is worth considering that there are many varieties of memory cards, in most cases incompatible with each other. On the other hand, chartplotters usually use a common standard media, most commonly SD or microSD.
Base map
The presence of a base card in the delivery set of the device.
The base map is a pre-installed map that is stored in the device's memory. Thus, a chartplotter in this configuration can (theoretically) be used out of the box without installing additional software. In fact, although basemaps may vary by model, manufacturer, and region, they are often small scale, displaying only the most general (often outdated) information, and unsuitable for professional use. Therefore, this function, usually, does not eliminate the need to install additional detailed maps (see below).
Adding new maps
Ability to load new navigation charts into the chartplotter.
This possibility is extremely important in the light of two points. First, the base map (see above) rarely provides the level of detail needed to be used effectively — you have to download more detailed maps of individual areas. Secondly, it is very desirable to update even already loaded maps from time to time, since hydrographic information (depths, currents, shoals, fairway location, etc.) is constantly changing.
Waypoints
The maximum number of individual waypoints that can be stored in the chartplotter's memory.
Waypoints can be used as a base for routing, as reference marks on a map, such a point can be set as an immediate destination, etc.; specific use cases depend on the instrument model. But anyway, the more waypoints you can simultaneously enter into the chartplotter's memory, the more convenient it is to work with them and the less often you have to clean this memory to make new marks.
Number of routes
The maximum number of tracks that can be stored in the chartplotter's memory at one time.
If you have to regularly travel on fixed routes, it is much more convenient to memorize these routes once and then select the desired option than to reprogram the navigator each time. Modern devices can store several tens or even hundreds of routes; the larger this number, the less often you have to free up memory for new routes.
