At CWN Marine, we’ve worked on a wide range of vessels, from coastal trawlers and offshore support ships to large commercial vessels navigating international waters. One thing remains consistent: the most common marine electronics failures we encounter are not caused by rare faults or high-seas disasters, they’re preventable. With regular inspections, correct installations, and proactive maintenance, vessel owners can avoid unnecessary breakdowns, downtime, and expensive callouts. In this article, we share the top five marine electronics failures we see most often, along with expert tips on how to prevent them.
The first, and perhaps most frequent, issue we encounter is corroded antenna connections. These failures typically present as poor or intermittent VHF, MF/HF, or AIS communication, often blamed on the equipment itself when the root cause is a simple case of salt corrosion. Antennas and cable connectors are highly exposed to the elements and particularly vulnerable to salt-laden air, humidity, and vibration. Over time, this leads to oxidised and weakened connections that disrupt signal strength. The solution is simple: inspect antenna bases and connectors every few months, apply waterproofing tape or compound to exposed connectors, and replace any visibly corroded components before they fail.
Another major source of frustration for vessel operators is power supply instability. This problem can cause critical systems to reboot unexpectedly, display errors, or shut down altogether. Often, it’s not a fault in the device but a symptom of fluctuating voltage from the onboard power supply. Loose wiring, unclean connections, or aging batteries can wreak havoc on sensitive marine electronics. Regularly checking voltage at the terminal, ensuring proper grounding, and keeping fuse panels clean and corrosion-free can prevent these disruptions. Batteries should also be tested and replaced on a routine schedule, particularly if you rely on backup systems in case of generator or shore power failure.
GPS failures are another routine culprit in the list of common issues. When a vessel loses GPS signal or reports incorrect positioning, it can compromise navigation, collision avoidance, and AIS accuracy. These failures often stem from damaged GPS antennas, poor cable routing, or interference from other electronic systems onboard. In some cases, the issue is simply outdated firmware that has not been updated in years. Ensuring that GPS antennas are positioned with a clear sky view, free from obstructions or interference from radar or satellite domes, goes a long way toward preventing problems. Cables should be inspected for wear or damage, and software updates from the manufacturer should be installed regularly to fix bugs and improve performance.
Radar degradation is another issue that creeps up slowly but can become a major hazard. Many operators only notice the problem once targets begin disappearing during bad weather or at long range. Common causes include contaminated or salt-encrusted radomes, a worn magnetron, or misaligned radar mounts, especially after dry-docking or heavy seas. Preventing radar failures involves regular cleaning of the radome, as even a thin layer of grime can degrade performance. Scheduling periodic tuning of the radar and checking the magnetron’s output helps keep returns sharp and reliable. Alignment should be checked at least once a year or any time the radar has sustained a knock.
Finally, AIS transmission issues are surprisingly common and frequently overlooked until a surveyor or port official points them out. We often find vessels broadcasting incorrect data or not appearing on nearby ships’ displays at all. This is typically due to incorrect configuration during installation, poor antenna placement, or GPS feed failure. To avoid these problems, it’s essential to follow manufacturer installation guidelines carefully, particularly around antenna separation and grounding. Vessel details such as MMSI number, dimensions, and ship type should be reviewed for accuracy, and the AIS system should be tested with diagnostic tools to ensure it is transmitting properly and within specification.
At CWN Marine, we believe that prevention is better than panic. While we’re always ready to step in when things go wrong, our goal is to help shipowners avoid these common and often costly failures entirely. Our preventative maintenance programmes are designed to reduce unplanned port stays, minimise operational delays, and keep your vessel compliant and ready to sail. We understand the pressure of tight schedules and limited layovers, which is why our service teams are equipped to work efficiently during port calls or in between voyages, without compromising on quality.
Whether you’re due for an inspection, experiencing signal issues, or planning a system upgrade, we’re here to help. Get in touch today to book a service call or request a free maintenance assessment.
