Understanding Digital Switching
Digital switching, one of the hot new trends on larger motor yachts, is designed to eliminate all the old issues that come with faulty wiring, huge cable runs and complicated systems. Corrosion is the curse of any electrical system, which includes the wiring. With the proliferation of electronics and electrical systems on modern boats, the cable runs have become substantial. Look behind the dash or bulkhead and there are wire bundles that lead to every corner of the vessel.
Rust Never Sleeps
Rust is a general term for a series of iron oxides, usually red oxides, formed by the reaction of iron and oxygen in the presence of water or air moisture. When in contact with water and oxygen, or other strong oxidants and/or acids, iron will rust. If salt is present, rusting speeds up because of the electro-chemical reactions. Rust is a common issue for all open-air connections. Galvanic corrosion is usually what people are talking about when they ask about electrolysis, but is actually the opposite. Galvanic corrosion is an electro-chemical reaction that causes electrons to flow from one metal to another metal.
As current flows between the two metals, the atoms from one are “sacrificed” and plated onto the other metal. This happens when there are dissimilar metals like aluminum and bronze close to each other. This occurs often when making wire connections. Stray current corrosion is similar to galvanic corrosion in that it eats away at underwater metal and fittings, but the cause is different. It is caused by electrical current in the water, introduced by a boat with a badly wired system.
Containing Current
This can be seen in boats with wires laying in the bilge leaking current. The stray current travels through bilge water and hull fittings to external metal such as props, trim tabs, lower units and outdrives, etc. Left unchecked, stray currents devour a boat’s metal equipment with ease. When people think of circuit protection they think of adding in-line fuses to a newly installed piece of equipment. This is not a wise choice for several reasons.
In-line fuses can trap water and corrode internally and they introduce two more splices in a circuit that shouldn’t have any. Another common issue is that many people forget where the fuse holders were installed, or once installed forget about them. It doesn’t take long before we have handfuls of inline fuse holders scattered about in a jury-rigged system. A boat full of in-line fuses, spliced and tapped wires can be a boat full of shorts, power leaks and corrosion. Ultimately this ends in fire, deteriorated metals and frustrating hours of tracing out dead shorts. A splice creates resistance and shortens the life of the component and the wire. A spliced wire creates as much as .01 to .03 Ohms per splice in resistance. That number climbs when the component is in use. This alone can cause a fire or component failure. So that’s where digital switching comes in.
What is Digital Switching?
Imagine being able to step on-board a vessel and, with the press of one button, turn on multiple circuits required for cruising. How about being able to shut down those systems with one switch at the end of a cruise? Digital switching, also known as a “networked control and monitoring system” brings that power and convenience of advanced home/vehicle automation to a boat.
Digital switching provides control of on-board electrical and electronic systems like lighting, air-conditioning, navigation lights, wipers, horns, entertainment systems, security systems, pumps and more from a network-connected multifunction display, smartphone, tablet or stand-alone screen. It replaces the standard mechanical circuit breakers and switches with state-of-the-art digital power distribution. This system offers convenient, reliable operation as well as simple and cost-effective installation. It also eliminates the space required for large AC/DC panels freeing up valuable space on-board for an extra locker or wine rack.
Stylish Simplicity
Instead of bulky, expensive switch panels, digital switching systems use compact digital circuit-control modules. Each one can support six circuits that are customized via software to meet the exact needs of the equipment being controlled. A typical digital switching system such as CZone has each module connecting to the vessel’s existing NMEA2000 network backbone. This enables communication with other modules and MFDs on-board. Flexible network architecture lets the modules be mounted near the equipment they control. This significantly cuts down on the size of the cable installed on the vessel. With more demand for helms to have a ‘clean’ look (reduced number of switches larger displays) the demand for networked control is becoming more prominent.
CZone has full integration with Simrad, Lowrance, B&G and Garmin 7000 and 8000 series displays. But the big CZone news is the new COI module packs the capabilities of five existing CZone modules into one less-expensive box. This can conceivably control all the power needs and many of the sensor needs of a modest vessel. The 14 power outputs can protect and switch most any circuits as long as the total amperage doesn’t exceed 150, and similarly the eight analog and six digital inputs can do all sorts of tasks.
Meanwhile the IN-D port is for boats that don’t use N2K interface and the USB port means that a CZone system with a COI can be programmed without a separate gateway. The COI module is effective for a wide range of boats and is especially targeted to 27’ to 33’ (8 m to 10 m) center consoles. In addition to wired controls, the Raymarine Digital Switching system, for example, also supports ENOcean wireless, energy harvesting switches and sensors. Free from the constraints of wires, ENOcean wireless devices bring a new level of freedom and flexibility to yacht system design.
This benefits the boat builder and owner by creating a system that is simpler to install and troubleshoot than traditionally switched systems. Significant cost savings can be realized thanks to faster installation and reduced amount of cable required to wire the vessel’s systems. Wire connections, runs and size can all be reduced, making the installation simpler and more efficient.
FinScan is a leading Australian designer and manufacturer of premium digital switching systems for marine and RV applications. FinScans NUCLEUS single module system, is the central component of the DC electrical system. It incorporates a power distribution module for DC electrical systems that provides all switching and circuit protection features. It eliminates the need for external DC electrical components like relays and fuses. In addition, FinScan has also included battery and tank monitoring in the NUCLEUS system. Bluetooth connectivity is also included.
Intuitive Monitors
A good monitor, with intuitive operation and clear, easy-to-read data that has been captured and processed from a myriad of functions caps off any good digital switching system. The brightness of the screen should be matched to the ambient light, ensuring glare-free operation while cruising at night and optimum readability during sunlight. Most displays now include an integrated touch screen. Monitor sizes range from around 10” (25.4 cm) to 24” (60.96 cm).
Features and Benefits
Most modern cars have some kind of auto switch that automatically turns on the lights if it starts to get dark or turn on the wipers if it detects rain. Digital switching lets a user integrate with an MFD, so it can detect SOG (speed over ground) and automatically determines the cruising speed and select a particular mode. If it reaches a certain time, say 7:30 p.m. and detects that navigation lights are off, it will illuminate them. A captain monitor information from the battery and tank levels, a charging system, an inverter and more data that can be brought into the system allowing full screen popups and audible alarms. There is hardly a system that can’t be monitored.