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A marine GPS chartplotter is very different from your everyday GPS device. What would be enough data for land-based navigation is not nearly enough for a chartplotter. When we are talking about natural obstacles like the shallow water or fog, you realize that for a chartplotter to work efficiently, there needs to be a far more sophisticated approach.

What most marine GPS chartplotter do excellently – and the Garmin GPSMAP 78sc is no exception – is providing a number of extra options compared to traditional GPS devices. These options and features can make your life at sea a little bit easier, and even save lives when needed.


  • Color display: The Garmin GPSMAP 78sc features a small albeit excellent screen. It has good size for a handheld GPS device, but its true strengths lie in the color display and the excellent viewing angles. It is readable under heavy sunlight, which should be a basic feature for any marine GPS device.
  • Wasp receiver: The device has a Wasp receiver with 12 channels. This means it receives corrections very quickly and accurately.
  • Barometer: The Garmin GPSMAP 78sc has an in-built barometer that can measure not only the atmospheric pressure but the altitude as well.
  • Three-axis compass: Thanks to the compass, the device is capable of what most similar GPS devices can’t, showing the right direction from a stationary position. It can do that because of the built-in compass.
  • Blue chart charts: The device has blue chart charts of the complete coastal areas of the United States. If you buy this device, you will not have to buy any chart cartridges. As long as you are close to the coast, you receive the high-quality blue chart charts.
  • Adaptability: The device has about 20 pages of information that you can choose. You can set up geocaching if you want to, or any other relevant data you want.
  • Chart slot: In addition to the blue chart charts provided by Garmin, the device has a separate chart slot as well. You can bring your Garmin microSD card and use it. This feature allows you to have city or inland navigation, or even international if that is what you need. The basic charts are excellent, but with this feature, you are not limited to them. You can add any number of chart cartridges if you wish.
  • AA batteries: The device uses two AA batteries that will operate it for more than 20 hours, possibly up to 24. This is excellent for a handheld marine GPS.
  • USB cable: Thanks to its USB cable, you can use the device off external power.
  • Waterproof and floats: The fact that a marine GPS is waterproof is not a surprise, but Garmin took the design to another level when they made it float. This feature can come in handy. Even if there is a big storm and you lose the gadget, you still have a chance of finding it. If you simply drop the unit into the water in clear weather, you don’t have to jump after it, you can simply grab it off the surface later.
  • GMP Map: The Garmin GPSMAP 78sc has a sophisticated map with many different modes and profiles. It is straightforward and highly customizable, or alternatively, you can choose between the different preloaded profiles. Recreational, geocaching, automotive, marine and fitness are just some of the available options. You can set the device up to support your activities to their fullest.
  • New software: One of the main differences between the previous models and the GPSMAP 78sc is the new software. The new design includes many software features, all of which are available on separate plot screens. There is a geocache screen, a hunting and fishing screen, a proximity alarm, a dangerous spot screen, and a wireless sharing screen, also a sight and go, a stopwatch function, a calculator for the moon phase, a track page, and many others.


  • New software
  • 6 inches readable color display
  • 20 to 24 hours of battery life
  • 5-pound weight
  • Map features
  • Waterproof and buoyant
  • USB cable
  • Chart slot for microSD


  • In rare cases, the maps won’t load


The GPSMAP 78sc is a highly efficient handheld marine GPS with a wide variety of features. It has a nice color display that provides excellent viewing angles, and a Wasp receiver that has 12 channels. In addition, the barometer provides accurate weather data and tells you the altitude. The three-axis compass allows the device to show the right direction even from a stationary position. The blue chart charts provide data for the coastal areas of the United States, real-time, until the boat is close to the coastline.

The device comes with an additional chart slot for the for Garmin microSD cards, which allows you to rely on city, inland or even international navigation features. The basic charts are excellent, but you don’t have to rely on them. The AA batteries are a very basic feature, but the fact that they last anywhere from 20, and up to 24 hours, makes them capable of providing consistent energy. The USB cable is another welcome addition, because you can also use the device while it relies on external power.

Garmin GPSMAP 78sc vs. Matsutec HP-33A 4.3″ Marine GPS Navigation

The Matsutec HP-33A 4.3’’ is a high marine GPS navigator that offers many of the same features as the Garmin GPSMAP 78sc. It boasts excellent software, a high-quality display with seven modes, and GOTO track navigation. From a technical standpoint, it can offer you a lot, and even includes an external alarm with a buzzer.


The Garmin GPSMAP 78sc wins almost entirely on the GPS-features. For a handheld marine GPS it has the same amount, if not more features than the Matsutec HP-33A 4.3’’. The display is not nearly as impressive, but a bigger one wouldn’t have been practical for the Garmin GPSMAP, and when it comes to features, it is the better of the two.