Common Causes of Marine Electronic Failure (And How to Avoid Them)

Modern recreational boating relies heavily on an integrated suite of marine electronics to ensure safe navigation, efficient power use, and onboard comfort. From GPS chartplotters and VHF radios to inverters and smart battery monitoring systems, these devices are more than conveniences—they’re vital tools for both short day trips and long offshore adventures.

But when marine electronics fail, the result can range from mild inconvenience to serious safety risks. Understanding what causes marine electronics to fail—and how to prevent it—is essential for any medium to large recreational boat owner.

This article explores the most common causes of marine electronic failure and gives actionable, preventative advice. We’ll focus on products from trusted marine technology brands like Victron Energy, Garmin, and Mastervolt, which are often at the heart of modern marine systems.

The Top Culprits Behind Marine Electronics Failures

Moisture Ingress and Corrosion

Water is your boat's biggest enemy when it comes to electronics. Even in sealed environments, the combination of salt, humidity, and condensation can lead to premature corrosion, especially on connectors, terminals, and circuit boards.

Signs of moisture-related failure:

• Erratic screen flickering

• Signal dropouts or GPS loss

• Device not powering on

• Visible green or white corrosion on connectors

How to prevent moisture damage:

• Use marine-grade waterproof connectors and shrink-wrap butt connectors

• Seal connections with dielectric grease

• Install desiccant packs inside consoles and junction boxes

• Keep electronics away from bilges and other high-humidity zones

• Victron Smart Battery Protect and SmartShunt offer weather-resistant housings but should still be mounted in dry, ventilated locations

Overheating and Poor Ventilation

Marine electronics need proper airflow to stay cool. High-load devices like inverters, chargers, and chartplotters are especially prone to overheating.

Typical symptoms:

• Sudden shutdowns under load

• Devices hot to the touch

• Displaying thermal error codes or derating performance

How to prevent overheating:

• Allow at least 2–4 inches of clearance around Victron MultiPlus or Mastervolt Mass Combi units

• Add ventilation fans to enclosed electronics bays

• Install heat-generating equipment away from direct sunlight or engine compartments

• Mount Garmin GPSMAP units where ambient air keeps them cool during operation

Electromagnetic Interference (EMI)

EMI, or electrical noise, can wreak havoc on your marine network. It's often caused by alternators, inverters, motors, LED lighting, and poorly routed cabling.

Symptoms of EMI:

• Inaccurate compass or heading sensor readings

• GPS latency or signal drop

• Intermittent Wi-Fi, Bluetooth, or VHF issues

• Screen flickering or jumping between modes

How to minimize EMI:

• Keep power cables and signal cables at least 12 inches apart

• Use shielded cables for NMEA 2000, Ethernet, and other data networks

• Properly ground your Victron and Mastervolt systems to the boat's bonding grid

• Install ferrite beads on data and power lines as needed

• Avoid daisy-chaining unrelated electronics together on the same power run

Firmware Bugs and Software Conflicts

Outdated firmware or incompatible versions across multiple devices can cause syncing issues, loss of data, and screen freezes.

Symptoms:

• Chartplotters that randomly reboot

• Network devices failing to appear or sync

• Incorrect voltage or power readings

• Errors during startup or shutdown

How to avoid firmware-related failures:

• Use Garmin ActiveCaptain to check and install the latest updates

• Update Victron devices via the VictronConnect app or GX touchscreen

• Back up configuration settings before upgrading firmware

• Coordinate updates across all networked devices during off-season

Installation Best Practices

Even the best electronics can fail due to poor installation. If you’re installing or upgrading components, always use:

• Tinned marine-grade wire

• Heat-shrink terminals and connectors

• Proper circuit protection sized for the load

• Branded components from Garmin, Mastervolt, or Victron whenever possible

Victron’s Lynx Distributor is an excellent solution for clean, modular fuse management. Mastervolt systems often include integrated protections, but verifying proper installation remains essential.

Diagnosing Before Replacing

Before assuming a device has failed:

• Check for LED indicators or screen activity

• Verify voltage at the power source and the device using a multimeter

• Inspect connectors for corrosion, chafing, or pin damage

• Use your Victron Cerbo GX or Garmin diagnostic tools to see logs or warning messages

• Check NMEA 2000 or Ethernet device presence using device lists on your chartplotter or MFD

Ongoing Maintenance Tips

Keeping electronics in peak condition doesn’t require constant attention—but it does benefit from routine check-ins.

Monthly:

• Wipe displays with soft, damp cloths

• Check for cable chafe or loose mounts

Seasonally:

• Update all firmware and software

• Clean all terminal strips, connectors, and fuse blocks

Annually:

• Load test batteries

• Inspect ventilation pathways for dust or obstruction

• Remove and inspect fuses and bus bars for corrosion

Trusted Products Worth Investing In

To reduce the chances of failure, use systems built for marine life:

• Garmin GPSMAP 8612xsv – Full-featured chartplotter with sonar, radar, and NMEA 2000 compatibility

• Victron MultiPlus-II – Reliable inverter/charger with advanced monitoring options

• Mastervolt Chargemaster Plus – Multi-bank charging solution with CAN and CZone support

• Victron SmartShunt – Simplified battery monitoring from your phone or Cerbo GX

Electronic failures on the water are more than a hassle—they’re a risk to safety and comfort. By understanding the most common causes, from overheating and moisture to EMI and outdated firmware, boaters can keep systems running smoothly and avoid costly downtime.

S & S Dockside Marine Supply is here to support you with the highest quality Garmin, Victron, and Mastervolt products, expert advice, and marine-grade components built to last. Whether you’re planning a refit or need help troubleshooting onboard electronics, count on S & S to help keep you powered and connected wherever your boating adventures take you.