Garmin GPSMAP 1643 16" Chartplotter GN+ (No Built-in Sonar)

The GPSMAP 1643 is Garmin's 16-inch chartplotter at the base of the GPSMAP 16-inch lineup, sitting below the 1643xs (CHIRP only) and the top-spec 1643xsv (Ultra HD SideVu, ClearVu, plus 1 kW CHIRP). The base 1643 ships without any built-in sonar at all. That sounds like a downgrade until you realize the actual use case. Plenty of larger cruising boats, commercial vessels, and yacht installs already have an external sonar black-box module on the network, or they don't run a fishfinder at all. For those installs the built-in sonar in the xsv is wasted spend. The base 1643 gives you the same 16-inch display, the same processor, and the same network connectivity at a meaningfully lower price. If you decide later you want to add sonar, the Garmin Marine Network accepts external sonar modules, Panoptix transducers, and LiveScope transducers without any change to the chartplotter itself.

The display is the headline. 16 inches of IPS panel with edge-to-edge glass and a high-brightness backlight that holds up in direct sun, polarized sunglasses, and the off-angle viewing you get when two people are reading the same screen from different sides of the helm. The wide viewing angle of IPS is the difference between a chartplotter that works at the helm chair and one that only the captain can read clearly. The processor under the panel is the upgraded GPSMAP 16-inch core, which handles overlay radar, multi-engine NMEA 2000 data, IP video feeds, and live sonar (when you network a Panoptix or LiveScope transducer to it) without the lag that older 12-inch combo units sometimes show when you stack too many features on one screen.

Network connectivity is the second major reason captains pick this unit. Dual Garmin Marine Network ports let you network this chartplotter to a second helm display, an open-array radar pedestal like the Fantom 5X, a Panoptix or LiveScope transducer, and a sonar black box all on the same Ethernet ring. NMEA 2000 and NMEA 0183 cover the rest of the boat's data: autopilots, VHF radios, AIS receivers, Fusion audio, and digital switching panels. The J1939 input speaks directly to heavy-diesel engine ECUs without a separate gateway, and Yamaha engine integration shows RPM, fuel burn, trim, and warnings directly on the chartplotter for owners running compatible Yamaha outboards. HDMI out feeds video to a second screen or a video distribution amp, which matters on multi-helm boats.

The Force trolling motor integration is where Garmin's ecosystem pays off for inshore and bass anglers. From the chartplotter you can steer the trolling motor, lock it on a heading or a waypoint, anchor virtually, and follow contour lines without touching the foot pedal. Power-Pole shallow-water anchors are also supported with auto-deploy, jog, and drag-detection features. CHARGE integration handles battery management across banks if you've got the matched alternator system installed. OneHelm digital switching consolidates third-party control panels (lights, pumps, accessories) into chartplotter screen pages so the helm stays uncluttered.

For sailors, the SailAssist feature set adds laylines for upwind and downwind tactics, wind roses with true and apparent wind angle overlays, polar tables for performance prediction, tide and current sliders, and a race-start countdown with line-bias calculator. It's not a substitute for a dedicated sailing instrument display, but for a cruiser-racer who wants navigation and sailing data on one big screen, it covers the basics well. Connectivity outside the boat runs through built-in Wi-Fi (ActiveCaptain app, software updates, Quickdraw map sync), Bluetooth (smart notifications), ANT+ (wireless sensors, watches), and inReach pairing for two-way satellite messaging from the chartplotter if you have an inReach subscription. The unit ships with Garmin Navionics+ charts pre-loaded for the US market, which is what the GN+ designation calls out. The optional Navionics Vision+ upgrade adds satellite imagery overlays and high-resolution bathymetric shading on top of the base Navionics+ data. The unit ships with a microSD card slot, power cable, NMEA drop cables, and both flush-mount and surface-mount hardware in the box.

If you specifically want sonar in the same box as the chartplotter, the 1643xs and 1643xsv variants are the right pick. If you've got a separate sonar module on the network or you don't fish at all, the base 1643 saves you a few hundred dollars without giving up anything you'd actually use.