The Garmin GPSMAP 421 is a compact chartplotter that features an ultra-bright 4” QVGA colour display along with an improved high-speed digital design for increased map drawing and panning speeds. It’s ready to go with a built-in, satellite-enhanced worldwide basemap and an easy-to-use interface designed to help you navigate the open waters with ease. The Garmin GPSMAP 421 also accepts BlueChart g2 Vision cards for added features and functionality such as high-resolution satellite imagery, 3D views and Auto Guidance technology.
View Satellite-enhanced Worldwide Basemap
The Garmin GPSMAP 421 basemap contains worldwide satellite images in place of traditional maps. The Garmin GPSMAP 421 also comes standard with a high-sensitivity GPS receiver for superior satellite tracking and quicker acquisition times. In addition, the GPSMAP 421 can receive U.S. graphical weather data via optional Garmin GXM 51 satellite receiver/antenna. And with an SD card slot, it’s easy to add additional maps without connecting to a computer.
Add Sonar
Where applicable, the sounder version, GPSMAP 421s, comes with a powerful dual-frequency transducer that clearly illustrates depth contours, fish targets and structures whether you’re fishing in freshwater or off the coast. The GPSMAP 421 and GPSMAP 421s are also NMEA 2000-certified for easy connectivity with sensors, instruments and future marine offerings.
Add Extras with BlueChart g2 Vision
With the optional Garmin BlueChart g2 Vision SD card, you can add a whole new dimension of exceptional features to your chartplotter.
- 3D Mariner’s and Fish Eye view provides you with a 3-dimensional perspective of map information, both above and below the waterline
- High-resolution satellite images and aerial photographs help you orient yourself in unfamiliar areas
- Auto Guidance technology searches through all relevant charts to create a route you can actually follow — one that avoids obstacles, shallow water, buoys and other obstructions
Garmin GPSMAP 421/421s Features & Specifications:
GPSMAP 421 and GPSMAP 421s
• Ultra-bright 4” diagonal QVGA display, 240 x 320 pixels – over 800 nits of brightness
• NMEA 2000 certified for seamless integration with the Garmin marine lineup
• Preloaded worldwide marine basemap
• Compatible with GXM™ 51 for XM Satellite Radio and XM WX Satellite Weather
• Built-in high-sensitivity GPS receiver
• High-speed processor for fast screen redraws and smooth panning
• Streamlined user interface makes it simple to select modes and features
• Single SD™ memory card slot for BlueChart g2 Vision cards, as well as saving waypoints, routes and tracks to a SD card
• Optional BlueChart g2 Vision cards provide marine chart detail and enhanced navigation features like Auto Guidance, satellite
imagery, 3-D Mariner’s Eye View and 3-D Fish Eye View
• Backlit keypad for easy operation in low light conditions
• Unit dimensions: 5.0”H x 5.7”W x 2.7”D (12.7cm H x 14.5cm W x 6.9cm D)
GPSMAP 421s
• Same features as listed above
• Power output: 500 watts (RMS) 4000 watts (peak to peak), dual frequency
• Depth: 1,500 feet / 500 meters (dual frequency)
• Use a dual frequency transducer 50kHz (45°), 200kHz (10°) for maximum saltwater performance
• Patented transom/trolling mount transducer
• UltraScroll® high rep rate sonar provides lightning-fast screen updates
• AutoGain technology enhances target visibility
• See-Thru® technology: shows weak and strong returns simultaneously
• Water temperature log graphically records water temp data
• A-scope
• Whiteline
• Adjustable depth line helps gauge desired fishing levels and bottom clearance
• Split zoom display offers a closer look at fish targets and bottom structure
• 2X, 4X and bottomlock zoom
• Adjustable keel offset
• Alarms for fish size, shallow water, deep water and low battery
| Physical & Performance: |
| Unit dimensions, WxHxD: |
5.7" x 5.0" x 2.7" (14.5 x 12.7 x 6.9 cm) |
| Display size, WxH: |
2.4" x 3.2", 4.0" diagonal (6.1 x 8.1 cm, 10.2 cm diagonal) |
| Display resolution, WxH: |
240 x 320 pixels |
| Display type: |
QVGA display |
| Weight: |
1.3 lb (590 g) |
| Battery: |
none |
| Battery life: |
none |
| Waterproof: |
yes (IPX7) |
| High-sensitivity receiver: |
yes |
| Antenna: |
internal |
| NMEA input/output: |
NMEA 0183 compatible and NMEA 2000 certified |
| Maps & Memory: |
| Basemap: |
yes |
| Preloaded maps: |
no |
| Ability to add maps: |
yes |
| Built-in memory: |
none (cannot load maps to internal memory) |
| Accepts data cards: |
SD™ card slot |
| Waypoints/favorites/locations: |
3,000 |
| Routes: |
100 |
| Track log: |
10,000 points; 50 saved tracks |
| Features: |
| Garmin radar compatible: |
no |
| Garmin sonar compatible: |
yes |
| CANet® compatible: |
no |
| Garmin Marine Network™ compatible: |
no |
| Touchscreen: |
no |
| Supports AIS (tracks target ships' position): |
yes |
| Supports DSC (displays position data from DSC capable VHF radio): |
yes |
| Audible alarms: |
yes |
| Tide tables: |
yes |
| Hunt/fish calendar: |
no |
| Sun and moon information: |
yes |
| 3-D map view: |
yes (with optional BlueChart g2 Vision card) |
| Auto Guidance: |
yes (with optional BlueChart g2 Vision card) |
| Automatic routing (turn by turn routing on roads): |
no |
| XM WX Weather & Radio for U.S. compatible: |
yes |
| Voice prompts (e.g. "Turn right in 500 ft."): |
no |
| Speaks street names (e.g. "Turn right ON ELM STREET in 500 ft."): |
no |
| Remote control: |
no |
| Headphone jack/audio line-out: |
no |
| Audio/video input/output: |
no |
| Portable: |
no |
| Automotive/motorcycle-friendly: |
no |
Garmin
GPSMAP 421/ 421s Chartplotters 
BlueChart
g2 Vision