Marine Electronics Buying Guide (2026) | CritPro

Fish finders, VHF radios, AIS, GPS, and NMEA 2000 networking: every marine electronics category explained, what to buy first, and how to build a complete electronics package from entry-level to fully integrated systems.

Marine electronics have become the largest variable separating a capable fishing and boating setup from a basic one. A well-equipped modern boat runs sonar that produces photographic-quality images of the bottom, a VHF radio that broadcasts GPS coordinates to the Coast Guard with a single button press, an AIS system that shows other vessel traffic on the chartplotter, and all of it networked through a single NMEA 2000 backbone that shares data between every device on the helm. Building that system does not require buying everything at once. What it requires is understanding what each category does, which products are worth the investment, and in what order to build the system as budget allows.

CritPro carries Humminbird fish finders and marine electronics, Standard Horizon, Uniden, and Icom VHF radios across the full range from entry-level to professional-grade systems. This guide covers every category and helps you choose the right equipment for your boat.

The Five Marine Electronics Categories

Marine electronics break into five functional categories, each addressing a distinct need on the water. Understanding what each one does before shopping prevents both overspending on features you will not use and underinvesting in the categories that matter most for how you actually fish and boat.

• Fish finders and sonar: Locate fish, read bottom structure, and understand depth and composition. The primary fishing electronics category.
• VHF radios: Marine communication and emergency distress signaling. The most important safety electronics category.
• GPS and chartplotters: Position, navigation, waypoint marking, and route planning. Integrated into most quality fish finders through combo units.
• AIS (Automatic Identification System): Vessel traffic awareness showing other AIS-equipped boats and ships on your display.
• Marine networking (NMEA 2000): The backbone that allows fish finders, radios, GPS antennas, and other devices to share data across a single cable network.

Category 1: Fish Finders and Sonar

A fish finder uses sound waves to map the water column between the boat and the bottom, producing a real-time display of depth, bottom composition, fish locations, and structure. Modern fish finders have advanced far beyond simple depth sounders into imaging sonar systems that produce near-photographic detail of what is below and beside the boat.

What to Look For

Display size matters for practical use on a moving boat. A 5-inch display requires leaning in to read the detail. A 7-inch display is readable from a normal fishing position. A 9-inch or larger display allows split-screen operation with multiple sonar views simultaneously. Match screen size to your boat and where the unit will be mounted relative to where you fish.

Sonar type determines what level of underwater detail you can see. Standard sonar shows depth and basic fish arches. Down Imaging adds a detailed near-photographic view directly below the boat. Side Imaging adds a wide lateral scan to both sides of the boat, revealing structure and fish out to 100 feet or more in each direction. MEGA Imaging is Humminbird's highest-frequency imaging format, producing the sharpest available underwater pictures at any imaging tier. For most freshwater bass fishing, the combination of MEGA Down Imaging and MEGA Side Imaging on a 7-inch display is the practical ideal.

GPS integration transforms a fish finder into a navigation tool. Built-in GPS allows marking productive waypoints, recording and following routes, and providing GPS position data to DSC VHF distress calls when the units are networked. Any fish finder you plan to use for more than casual use should have GPS.

Humminbird Fish Finders at CritPro

CritPro carries the full Humminbird lineup from the entry-level HELIX 5 to the flagship XPLORE 9. Humminbird is one of the most respected fish finder manufacturers in the market, with MEGA Imaging, AutoChart Live mapping, and deep Minn Kota trolling motor integration through i-Pilot Link. Key models:

• HELIX 5 DI G2 ($313.95): The best-value entry into Down Imaging. 5-inch display, Down Imaging for structural detail, CHIRP sonar. The starting point for anyone adding fish finder capability for the first time.
• HELIX 7 CHIRP MEGA DI GPS ($678.95): The sweet spot for most freshwater bass boat applications. 7-inch display, MEGA Down Imaging, built-in GPS. Readable from a normal boat position and sharp enough to identify structure clearly.
• HELIX 7 MEGA SI GPS G4N ($999.99): Adds MEGA Side Imaging to the HELIX 7 platform, revealing structure and fish laterally out to 100 feet on each side. The most impactful upgrade for anglers who fish unfamiliar water or large reservoirs where covering structure efficiently is the key to finding fish.
• XPLORE 9 CMSI+ ($1,499.99): 9-inch display with CHIRP MEGA Side Imaging Plus. The flagship unit for tournament anglers and serious guides who want the best available sonar in a large display format.

Browse the full fish finder selection at CritPro for the complete Humminbird lineup.

Category 2: VHF Radios

A marine VHF radio is the most important piece of safety electronics on any boat. It operates on Channel 16, monitored continuously by the Coast Guard and nearby vessels, and provides a communication link that works where cell phones do not. A DSC-equipped VHF radio broadcasts your GPS position to the Coast Guard with a single button press, which is the fastest and most effective way to summon help in a marine emergency.

The two key decisions are fixed-mount vs handheld, and which brand/tier fits your budget and use case. Fixed-mount 25-watt radios provide far better range (20 to 30 miles) than handheld 5 to 6 watt units (3 to 8 miles). Both have their place on a well-equipped boat.

VHF Radios by Budget Tier at CritPro

Budget (Uniden): The Uniden MHS75 at $116.95 is the best-value DSC submersible handheld in the market. For a fixed-mount entry point with Icom quality, the Icom IC-M330 at $200.95 delivers 25 watts in the most compact fixed-mount Icom produces.

Mid-range (Standard Horizon): The Standard Horizon GX1850 at $399.99 is the most practical fixed-mount VHF for most recreational boats: 25 watts, DSC, NMEA 2000 connectivity, NOAA weather, Hailer/PA. The GX2410GPS at $499.99 adds built-in GPS and AIS receive.

Premium (Icom): The Icom IC-M510 Plus at $741.95 includes a built-in AIS transceiver, GPS, NMEA 2000, and CommandMic IV compatibility. The Icom IC-M605 with AIS at $1,049.95 is the flagship with a color display and full AIS transceive capability.

For the complete breakdown of every VHF radio model at CritPro across Uniden, Standard Horizon, and Icom, see the CritPro Marine VHF Radio Guide. Browse all VHF radios and antennas at CritPro.

Category 3: GPS and Chartplotters

GPS provides your boat's position, speed, and heading. A chartplotter overlays that GPS data on a navigational chart, showing your position on the map in real time along with depth contours, waypoints, routes, and other navigational information. For most recreational fishing boats, a combo unit that integrates sonar and chartplotter in one display is the practical choice over separate dedicated devices.

Humminbird's HELIX and XPLORE units include built-in GPS and cartography capability in every model that carries the "GPS" designation in its name. AutoChart Live allows you to create your own custom depth maps of any water you fish, building a high-resolution map over time as you run the unit across a lake or river system. This is one of the most valuable features for anglers who regularly fish the same bodies of water and want better contour detail than factory maps provide.

For dedicated navigation applications on larger vessels, a standalone chartplotter separate from the sonar unit provides a larger mapping display optimized for navigation rather than splitting screen real estate between sonar and chart views. Most serious fishing boats above 22 feet eventually run both: a primary sonar combo for fishing and a separate chartplotter or MFD (multifunction display) for navigation.

Category 4: AIS

AIS (Automatic Identification System) is a vessel tracking system that provides real-time awareness of other AIS-equipped vessels in your vicinity. Commercial ships, large recreational vessels, and an increasing number of smaller boats broadcast their position, speed, heading, and identification via AIS continuously. A boat with AIS receive capability displays this traffic on its chartplotter or VHF radio screen, providing collision avoidance awareness that visual scanning alone cannot provide in low visibility, busy shipping channels, or when operating at night.

AIS is available in two forms: receive-only (shows other vessels to you but does not broadcast your position) and transceive (Class B transponder that both receives and broadcasts). AIS receive is built into several VHF radios at CritPro, including the Standard Horizon GX2410GPS and the Icom IC-M510 Plus and IC-M605 models. For inshore saltwater fishing along the Georgia coast where commercial ferry traffic, cargo vessel approaches, and recreational boat density can be high, AIS receive adds meaningful situational awareness.

Category 5: NMEA 2000 Networking

NMEA 2000 is the marine industry standard networking protocol that allows electronics devices to share data over a single backbone cable. When devices are networked via NMEA 2000, your VHF radio can receive GPS position data from the chartplotter and include it automatically in DSC distress calls. Your fish finder can display speed and heading data from a GPS antenna. Your engine instruments can send data to the chartplotter. Your trolling motor can share sonar data with the fish finder.

Planning for NMEA 2000 from the beginning of a marine electronics build is significantly easier and less expensive than retrofitting it later. The backbone is a simple daisy-chain network of compatible connectors and drop cables that allows new devices to be added without rewiring the entire system. Most quality marine electronics at CritPro, including the Standard Horizon GX1850, Icom IC-M510, and Humminbird HELIX 7 G4N models, include NMEA 2000 connectivity.

Building a Marine Electronics System by Budget

Installation Basics: What Every DIY Install Needs

Installing marine electronics correctly matters more than the choice of brand or model in many cases. A poorly installed unit with interference from other electrical systems, a transducer mounted in turbulent water, or a VHF antenna with a poor connection produces worse results than a correctly installed entry-level setup. A few installation fundamentals worth knowing before starting:

• Transducer placement is critical for fish finders. The transducer must be mounted in smooth water flow, away from turbulence created by the hull, strakes, or hull hardware. For in-hull installations, test placement by filling the void with water before permanent mounting.
• VHF antenna height matters. Range is primarily determined by antenna height. A properly installed external antenna mounted at the top of the T-top or hardtop produces significantly better range than a short antenna mounted at gunnel height.
• Fusing and wiring gauge. Every marine electronics circuit should be individually fused as close to the battery as practical, using the correct gauge wire for the current draw and run length. Undersized wire and unfused circuits are the primary cause of marine electrical fires.
• NMEA 2000 backbone planning. Plan the backbone route before installing any devices so you can run it cleanly with proper drop cable lengths. A messy NMEA 2000 install with too many T-connectors or improper termination causes data errors across all connected devices.

Related Marine Guides at CritPro

• Shop Fish Finders at CritPro
• Shop VHF Radios and Antennas at CritPro
• Shop Marine Battery Chargers at CritPro
• Best Marine VHF Radios Guide
• Marine Battery Charger Buying Guide

Frequently Asked Questions About Marine Electronics

What should I buy first: a fish finder or a VHF radio?

A VHF radio. A fish finder improves fishing. A VHF radio can save your life. If your boat does not yet have a working VHF radio, that is the first marine electronics investment regardless of budget. A $76.95 Uniden Atlantis 155 handheld provides Channel 16 monitoring and basic VHF capability immediately at minimal cost while you save toward a fixed-mount installation or a better fish finder.

Do I need a separate chartplotter and fish finder?

For most recreational fishing boats, a combo unit that integrates sonar and GPS chartplotter in a single display is the right choice. Separate units make sense when you want a dedicated large-format navigation display at the helm alongside a sonar-optimized display at the bow, which is common on larger center consoles and dedicated tournament bass boats with dual-console setups.

What is NMEA 2000 and do I need it?

NMEA 2000 is the marine electronics networking standard that allows devices to share data over a single cable. If you plan to run more than one marine electronics device on your boat, including a fish finder, VHF radio, and eventually an autopilot or engine instruments, NMEA 2000 compatibility makes the system significantly more capable. Buy NMEA 2000-compatible devices from the start and run the backbone when you install your first unit, even if you are only connecting one device to begin with. Adding devices later becomes much simpler.

What is the difference between AIS receive and AIS transceive?

AIS receive shows you other vessels that are broadcasting AIS signals. AIS transceive does that and also broadcasts your own position to other vessels. For most recreational inshore fishing, AIS receive is the more practical feature, providing awareness of commercial traffic and other vessels without the added cost and registration requirements of a Class B transponder. The Icom IC-M510 Plus includes AIS transceive; the Standard Horizon GX2410GPS includes AIS receive only.

How do I keep marine electronics from corroding in saltwater?

Use dielectric grease on all electrical connections, particularly at the back of the unit and any exposed connectors. Rinse the exterior of fixed-mount units with fresh water after every saltwater trip. For cockpit-mounted units with exposed controls, confirm the waterproof rating meets or exceeds the environment they will be installed in. Rinse handheld VHF radios with fresh water after saltwater exposure and confirm the sealing gaskets are in good condition at least annually.

Final Verdict: Build in the Right Order

Start with the VHF radio. Add a fish finder with GPS when budget allows, choosing the screen size and imaging capability that matches your primary fishing application. Plan NMEA 2000 connectivity from the beginning even if you are only installing one device today. Add AIS receive through a GPS-equipped VHF or a standalone receiver when you are regularly operating on busy coastal waters where commercial traffic and vessel density create real collision risk. The system does not need to be built all at once, but each device you add should be compatible with the next ones you plan to buy.

Browse the full marine electronics selection at CritPro across Humminbird, Standard Horizon, Uniden, and Icom, veteran-owned and ships fast from Jesup, Georgia.