Life on the water presents unique challenges for electronic equipment. Ships, tugboats, and other marine vessels rely heavily on sensitive navigation systems, communications equipment, control systems, and other onboard electronics. Protecting this equipment from damaging power disturbances is not optional—it’s mission-critical.
When it comes to surge protection, two main technologies are used: MOV (metal oxide varistor)–based devices and series mode surge protectors. While MOV devices are common, they are not well-suited for the harsh, high-stakes environment of marine applications. Here’s why series mode surge protection is the smarter choice for vessels.
1. MOVs Fail—and Often Catastrophically
MOV-based surge protectors work by “clamping” voltage surges and diverting both the surge and useful energy to ground during the surge event. Over time, every hit degrades the MOV component, which means the protector itself is wearing out each time it does its job. Eventually, it fails—sometimes by overheating, smoking, or catching fire.
On a vessel where space is tight and safety is paramount, a surge protector that can fail catastrophically is a liability no one needs. Series mode technology, on the other hand, does not degrade or rely on sacrificial components. It protects reliably for years without failure.
2. Ungrounded Power Systems on Ships
Marine electrical systems are often isolated or have floating grounds—especially on ships and tugboats. MOV-based protectors need a solid ground to function properly. Without it, they may not provide protection at all, leaving equipment exposed while creating a dangerous situation.
Series mode surge protectors, however, do not require a ground connection to work. They filter damaging surges at the source, making them ideal for the grounded, ungrounded, or floating power systems commonly found on vessels.
3. Fire Safety and Harsh Environments
Ships and tugboats already face tough operating conditions: environmental exposure and EMI/RFI noise due to equipment being located as close together as possible. The last thing you want in this environment is a surge protector that can go into thermal runaway and create a fire hazard.
Series mode surge protectors are designed with no failure-prone parts. They provide consistent protection without introducing safety risks.
4. Continuous, Noise Filtration for Sensitive Equipment
Marine electronics—from GPS navigation and sonar to communication radios and engine controls—must operate without disruption. MOV devices not only wear out but can also introduce electrical noise.
Series mode technology filters both surges and EMI/RFI noise disturbances without degrading performance over time. This means uninterrupted reliability for the equipment crews depend on.
5. Long-Term Cost Savings
While MOV-based surge protectors may seem inexpensive up front, their limited lifespan and replacement costs add up quickly—especially when factoring in the downtime and potential damage to mission-critical equipment.
Series mode surge protectors are built to last for decades without needing replacement, delivering far greater value and peace of mind for vessel operators.
Conclusion: The Safer, Smarter Choice for Marine Applications
For ships, tugboats, and other vessels, surge protection is not just about protecting equipment—it’s about safeguarding crew, mission, and operations. MOV-based surge protectors introduce too many risks in a marine environment: fire hazards, degradation, and dependence on ground systems.
Series mode surge protectors, by contrast, offer robust, long-lasting, and maintenance-free protection perfectly suited for the demands of the sea.

If you want your vessel’s electronics to be protected reliably—without the risks associated with MOV devices—series mode surge protection is the clear choice.