How to Choose a Marine Chartplotter: Screen Size, Charts, and Networking Explained

1. Screen Size: Match It to Your Boat

Screen size on a chartplotter is a practical decision, not an aesthetic one. The right size depends on the size of your boat, how far you typically stand from the screen when at the helm, and how much information you need to see at once.

One consideration often overlooked: sunlight readability. A chartplotter that reads well in a showroom can be nearly invisible at noon in direct sun on the water. Look for units with a high nit brightness rating (500 nits minimum, 1000+ for bright conditions) and an IPS or MFD-grade display rather than a standard LCD panel.

2. Charts and Map Coverage

The chartplotter hardware is only half the equation. The quality and coverage of the charts it runs are what determine whether the unit is actually useful on your water. Most units come with a basemap or regional chart package preloaded, with options to expand coverage through paid chart cards or subscriptions.

The practical question to ask before buying: does the chart package cover the specific waters you fish or cruise? A unit with excellent offshore charts is not the right choice for someone who fishes inland lakes exclusively, and vice versa. Most manufacturers let you preview chart coverage on their website before purchase.

3. Standalone Chartplotter or Combo Unit?

Modern chartplotters almost universally include fishfinder/sonar capability in the same unit, which raises the question of whether a dedicated standalone chartplotter makes sense at all for most boaters.

For most recreational boaters under 35 feet, a combo unit (chartplotter plus CHIRP sonar) is the more practical choice. You get both navigation and fish-finding on one screen, in one installation, at a lower total cost than buying separate units. The displays are shared via split-screen, which is functional and sufficient for most use cases.

Standalone chartplotters without integrated sonar make sense in a few specific situations:

• Larger vessels with dedicated helm stations where you want a large navigation display separate from a fishfinder
• Boats that already have a quality fishfinder and need to add or upgrade navigation only
• Commercial or professional applications where navigation and sonar are managed from separate stations

If you're starting from scratch on a recreational vessel, a combo unit is almost always the right starting point. Our fishfinder buying guide covers the sonar side of that decision in more detail.

4. Networking: NMEA 2000 and What It Means for You

NMEA 2000 is the open standard network that lets marine electronics share data across a single cable backbone. When your chartplotter is connected to an NMEA 2000 network, it can display engine data, fuel levels, wind speed, depth from a separate sonar module, AIS vessel traffic, and data from other instruments, all on the same screen, without a separate wire run for each device.

For a simple setup with one chartplotter and no other electronics, NMEA 2000 connectivity is less critical. For a boat with multiple instruments, a VHF radio with DSC, autopilot, or engine monitoring, it becomes the difference between a system that talks to itself coherently and one that requires you to look at six different screens to get a complete picture of what's happening.

Most modern chartplotters from Garmin, Humminbird, Lowrance, Simrad, and Raymarine support NMEA 2000 as standard. Where the systems diverge is in proprietary networking features: Garmin's OneHelm, Simrad's GoFree, and Raymarine's Axiom system each offer advanced cross-device integration within their own brand family that isn't available across brands. If you're building a multi-device system, staying within one brand makes setup and future upgrades significantly simpler.

5. Controls: Touchscreen, Keypad, or Both?

This is a more practical consideration than it looks. Touchscreens are intuitive and fast in calm conditions at the dock. On the water, at speed, with wet hands, they can be significantly harder to use accurately than physical buttons and a rotary knob.

Most mid-range and premium chartplotters in 2026 offer hybrid control: a touchscreen for the main interface combined with physical buttons for critical functions and zoom. This is generally the best configuration for on-water use, particularly for boaters who spend time in rough conditions or at the helm in heavy spray.

Full touchscreen units work well for calm-water fishing, marina navigation, and any situation where you're moving slowly or stopped. If you run offshore regularly or in conditions where accurate screen taps aren't reliable, verify that the unit you're considering has physical key assistance before buying.