Skip Links

The Lowdown on Digital Switching

The ‘connected’ boat delivers real-time control and monitoring of everything happening aboard – even when owners are miles away

Hand interacting with a Black Raymarine hybridtouch and adjusting the exterior controls.

Photo: Garmin

Digital switching has become a major trend in the boating world. While typically associated with larger yachts, the technology is rapidly finding its way onto smaller craft of all stripes. What exactly is digital switching, and is it really the wave of the future? Here’s a quick look at the basics of digital switching.

While you may not be familiar with the growing marine use of digital switching, your car or truck has used some form of it for decades. Digital switching is a networked control and monitoring system that replaces conventional DC mechanical circuit breakers and switches with a digital power distribution/switching system. It uses NMEA2000, a communication standard used in the marine industry for connecting and sharing data between the various instruments and sensors found on boats, including depth sounders, autopilots, engines, and multifunction displays (MFDs). NMEA2000 is based on the Controller Area Network (CAN) protocol, a high-speed, low-level communication protocol used in a wide variety of industries.

Digital switching uses microprocessor-based circuit protection and monitoring, providing a significant reduction in wiring, breakers, and other traditional methods of distributing power, along with the additional weight associated with them.

A digital switching system still brings in the power to the user (the bilge pump, for example) from the battery, but this power is not passed through a circuit board or switching panel at the helm. Nor does it pass through circuit breakers and the connections that can be associated with them. Instead, it goes to the user or to a zone of users.

The control and monitoring of that power is derived at the zone or individual user from the digital switching module, which transfers the packets of data that control and monitor the user(s). The packets of data travel very quickly through the NMEA2000 cable between, for example, an MFD or cellphone, and the digital switching module that quickly shunts the data packet commands to or from the pump switch inside the module (which makes or breaks the circuit) and the person, alarm, or whatever. The digital switching module also monitors the power to the user at the site of the user, transmitting back, in data packets, info of a problem such as over-voltage. An additional feature of “digital switching” is that it allows you to program how it acts or reacts.

Black power distribution system.

Photo: Garmin

Black Raymarine hybridtouch displaying the interior controls of a vessel

Photo: Garmin

A traditional DC power distribution system uses a main or primary electrical panel powered via large cables from the boat’s battery. A dedicated wire run from the main panel then provides power to each individual circuit and the point of use (a bilge pump for example).

While a digital switching system also typically brings in a single source of power from the battery, it provides a single connection to each load. This eliminates the multiple, individual connections at circuit breaker, switch, and load required in a traditional distribution system.

This approach greatly improves system reliability, as it replaces exposed, corrosion-prone switching gear with a highly reliable, weather-sealed package. In addition to the corrosion issue, digital switching also eliminates the mechanical failure associated with the many moving parts of traditional breakers and switches. The use of these digital circuit breakers additionally allows the system to sense the electrical currents passing through them and (if it fails) to alert you by sounding and/or displaying an alarm.

As this digital system is programmable, users can control onboard electrical and electronic systems (e.g., lighting, security systems, bilge pumps) from any point in the NMEA network around the boat using a network-connected MFD, smartphone, or tablet.


Not all digital switch systems will have all the features outlined here. However, use this as a guide for asking questions about a particular system.

Digital switching benefits at a glance

  • “Plug-and-play” components. Connect them to the system and they automatically configure themselves.
  • Replaces bulky, expensive switch panels and wire runs with smaller cabling less prone to connection issues and corrosion, and digital control modules, reducing installation cost and complexity.
  • Greatly simplifies system installations. Digital switching offers many advantages to the builder/installer: more effective modular system installation, flexibility in layout, easy system expandability, cost and weight savings from reduced cabling runs/sizes, plus a reduction in conventional hard-wired switches leading to cleaner/simpler helm consoles.
  • Systems are user-customizable. Need your bilge pump to stay on a predetermined time after pressing the on button? How about having the system monitor the freshwater tank and turning off the freshwater pump when it reaches a certain level? No problem — you can easily program the system to do both!
  • Easier troubleshooting with system failure notification. Those fancy touch-screen buttons are not just high-tech, virtual-reality versions of electromechanical on/off switches. When you turn that anchor light on, the system knows the current draw and voltage level that should be passing through it and will alert you if something is amiss via icons on the display.
  • Increased reliability by eliminating corrosion-prone mechanical switches and wire connections.
  • Lets you call up virtual buttons on one or multiple compatible touchscreen multifunction displays.
  • Easier to repair, update, or upgrade. For example, if a module fails, in most cases the system will automatically program the replacement module when it is plugged in. This means replacement can be successfully completed by the end user without the need for a service call. Upgrades to the system are also simpler. Let’s say a boat owner wants to add some additional function to their system, such as the ability to dim cabin lights, after using it for a while. Upgrading a digital switching system to allow this (depending on the one installed) can be as simple as the owner plugging in a USB flash stick or installing an online download, with no technician or additional hardware required. — F.L.
Numerous tangled red, blue and yellow wires of a digital switching module.

 Digital switching significantly reduces the amount of wiring necessary. Compare this setup with a traditional distribution system. Photo: Frank Lanier  

Clean and organized wires in a digital switcher.

The digital switching module transfers packets of data between various NMEA2000-compatible units such as a cellphone and a multifunction display. Photo: Frank Lanier  

Another great feature is the ability to energize groups or series of switching operations with the press of a single touchscreen button. Through the wonders of programmable digital switching, you can now step on board and turn on all of the electrical systems and electronics you’ll need for a day of fishing or a week of cruising with a single button. Once back at the dock, a single button can again be used to shut down multiple systems (no more running around to different circuit-breaker panels) while leaving required systems up and running.

Just realized you forget to turn the stereo system off or the bilge alarm system on after that two-hour drive from the marina? With a digital switching system, you can do both from home.

Related Articles


Click to explore related articles

technology electronics


Frank Lanier

Contributing Editor, BoatUS Magazine

Capt. Frank Lanier is a SAMS-accredited marine surveyor with over 40 years of experience in the marine and diving industries. He’s an author, public speaker, and multiple award-winning journalist whose articles on boat maintenance, repair, and seamanship appear regularly in numerous marine publications worldwide. Contact him via his YouTube channel “Everything Boats with Capt. Frank Lanier” or at