Is it time for your electrical system to go digital?
Does the idea of being able to monitor your boat’s systems remotely via your smartphone or tablet sound interesting? How about one-button selection for all commonly used daytime electrical gear and another that would turn on all of the equipment used during nighttime operation — would that put a smile on your face? This functionality represents just several of the many capabilities available on a new generation of boats employing digital switching for their electrical systems.
Digital switching is not really new — these systems have been employed in residential, automotive and aircraft applications for some time. The superyacht sector has also incorporated distributed power/digital switching systems for many years. And although we began seeing this technology migrate to smaller boats six or seven years ago, early growing pains, combined with a weak economy, stalled any momentum — most builders returned to installing what they knew well: old-style analog systems. As the economy rebounds, digital switching is becoming more common on both power- and sailboats smaller than 50 feet. In fact, the new buzz phrase heard within the industry and at boat shows around the country is “the connected boat.”
How does digital switching work?
Unlike conventional analog marine electrical systems, digital ones do not employ mechanical contacts inside the switch, eliminating such problems as excessive voltage drop due to corrosion, damaged contacts due to electrical arcing, the use of undersized cabling to save weight and money, and loose terminal connections caused by normal wear and tear or faulty workmanship. To overcome these problems, old tech systems need lots of large-gauge cabling that is both heavy and becoming quite expensive as copper prices continue to rise. Switches, fuses and circuit breakers, panel boards and traditional bus bars add weight and consume considerable real estate on board to make a quality analog system function as it should. Digital systems, on the other hand, turn things on and off and direct current flow utilizing electronically controlled MOSFETs, commonly known as transistors. With black box switching and conversion to digital signals distributed over a network, CAN bus or NMEA 2000, there is a significant reduction in the number of components and the amount of heavy-gauge wiring needed to distribute electrical power.
Once these functions are converted to digital format, integration with other electronic systems is made possible and the introduction of firmware and software programming can be made. Good examples of this are the Mastervolt/BEP C-Zone partnership with Garmin and EmpirBus joining with Raymarine. These alliances allow for switching technology to be integrated into the multifunction displays that are now commonplace on boats. Furthermore, by adding NMEA 2000 capability to these systems, seamless connections to critical engine data can also be accomplished, and connectivity to electronic equipment, as supplied by companies such as Simrad, B&G and Lowrance, is relatively easy.
A good example of how this plays out can be seen in Scout Boats’ newest offerings. Scout has emerged as one of the leaders in this connected boat concept and is one of the first to bring it to the center console market. Scout’s newest center consoles offer simple control of a mix of C-Zone digital switching and networking linked via Garmin displays and NMEA 2000 to the Yamaha outboards.
Why go digital?
One of the most compelling arguments for moving to digital switching is the ability to have a multitude of data inputs sent to one common location. This allows you to check everything from engine hours to fuel flow, exact location, radar data and the engine coolant temperature for your generator by scrolling through pages on a single touchscreen. You can also monitor what is actually turned on or off and determine whether an overcurrent protection device for a given circuit has been activated, all by looking at one intuitive display.
All of the wiring and data cable connections in these systems are completely waterproof and latched in place with the use of Amphenol, Deutsch and Molex-type cable connectors, which are commonly used in automotive applications. This virtually eliminates termination failures caused by vibration or faulty workmanship. Many of the digital switching components that I’ve inspected in recent years are epoxy-potted and typically use the latching Deutsch connectors, which make the system nearly submersible and immune to the effects of loose connections found in traditional systems. This contributes to a significant leap in long-term reliability over traditional hardware. For networked systems that don’t utilize these connector types or systems utilizing traditional CAT 5 cabling, which is latching but not watertight, mounting gear inside an IP waterproof-rated enclosure can take care of any moisture ingress issues.
The ultimate remote control
Another argument for moving to digital technology is programmability and wireless connectivity. Being able to connect to boat systems using a key fob, much as we can with modern automobiles, is a reality. Monitoring on-board systems and activities with an iPad or smartphone is possible with these systems. Imagine getting a text message from your boat telling you that battery voltage is too low and you need to attend to this matter.
Installers can program overcurrent protection ratings for every electrical circuit on board to more exacting standards than they are capable of with traditional fuses and circuit breakers, a definite safety advantage.
With digital systems, you can decide when and for how long certain circuits will be turned on. Automatic electrical load shedding can be configured if available power doesn’t coincide with demand, or the system can be configured to automatically turn on an inverter or generator to meet the current need. Light dimming can also be accomplished via the digital system, eliminating the need for separate dimmer switches. The list goes on and on — and keep in mind, none of this capability can be achieved with traditional analog electrical systems.
Room to grow and reliability
Expanding a system as new on-board accessories are added is as easy as plugging in additional input/output modules and inputting simple programming commands that most owners can accomplish with relative ease.
Naysayers will expound for hours about the risks of relying on electronic equipment in mission-critical situations. All of this naysaying brings me back to the mid-1970s, when electronic ignition and electronic fuel injection systems were in their infancy. The argument then was if my points fail and the carburetor acts up, I can fix it with a matchbook cover and a gum wrapper and get home. The reality is that equipment has become so reliable in the last 40 years that I don’t buy into these fears about digital switching. The automotive industry has made these systems work under conditions far harsher than any boat ever is exposed to: broad temperature changes; running through deep puddles, often loaded with salt to melt ice and snow; bumpy roads and potholes — all of these real-world environmental situations have been commonplace. We are driving the most reliable vehicles ever today, in large part because of electronic integration. Achieving this sort of reliability in the marine realm should be comparatively easy.
Last but not least
What about a lightning strike? Odds are your engine, either gas or diesel, is partially or completely electronically controlled — lightning will, in all probability, knock it out of service. Navigation and communication gear is at risk. As for the digital vs. analog electrical system, the digital system has some redundancy — all of the systems I’m familiar with have back-up traditional fuse modules that can easily reactivate a circuit as long as the electronic module that controls things hasn’t been damaged. To add a further degree of reliability, several of these systems now comply with American Boat and Yacht Council standards.
The bottom line on lightning is that it’s always safer to avoid it.
For more about digital switching:
Digital Switching Systems, Omni-BUS: www.digitalswitchingsystems.com
E-T-A PowerPlex: www.e-t-a.com
Ed Sherman is director of educational programming for the American Boat and Yacht Council.
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January 2014 issue