Thanks to NMEA 2000, boat owners shouldn't pine for the old days when it comes to installing new electronics.
IT ONLY TAKES a quick peek at the electronics installation aboard any modern boat to confirm what my grandpa used to say: “Things just ain’t like they used to be!” In the Wild West days of electronics installations, adding new gear meant snaking a plethora of spaghetti-like, multicolored wires around the helm between the equipment, a power source and whatever remote sensor was involved (e.g., transducer, wind indicator). Data-sharing between equipment was essentially an electronic Tower of Babble. Installations required an almost professional-level of installer knowledge to connect different boxes together. And what if the new electronic doodad was from a different manufacturer? Fuhgettaboutit! Plugs were different, wire color codes were different, and even if you could Frankenstein them together, many didn’t even speak the same language.
Today, most any form of onboard information, from chartplotters to engine data, can be easily linked together by even the most novice DIYer, and varied pieces of equipment can exchange, process and display each other’s information — all thanks primarily to the vision and efforts of one group and the standards it developed.
What it Is, What it Was
The National Marine Electronics Association (nmea.org) was founded by a group of electronics dealers at the 1957 New York Boat Show. The goal of that meeting was to discuss how to strengthen relationships between electronic manufacturers. Fast forward to 1983, the year NMEA introduced NMEA 0183, a voluntary industry standard to facilitate data communications between different marine electronics products. NMEA 0183 is an ASCII, serial communications protocol that defines how data is transmitted from one piece of gear, or ‘talker,’ to one or more ‘listeners’ at a time. While groundbreaking at the time, it’s a pretty simple protocol (compared to today’s standards) and not without limitations. Data transmission rates are slower, and since it doesn’t allow for multiple talkers, it can’t be used to create networks.
Despite its shortcomings, NMEA 0183 is still widely used and remains a perfectly acceptable way to integrate two sets of data, such as a chartplotter GPS to a fixed-mount VHF for DSC capabilities. Even so, NMEA 0183 has largely been supplanted by NMEA 2000, although many current devices can communicate using either protocol.NMEA 2000
The current industry standard is NMEA 2000, a plug-and-play networking system for the marine industry that allows quick and easy installation of new equipment. NMEA 2000 (abbreviated to N2K) uses a compact binary message format, rather than the ASCII serial communications protocol used by NMEA 0183, and supports a disciplined multiple-talker, multiple-listener data network, allowing multiple units to simultaneously transmit and receive data through a single, standardized cable.
Combined with multifunction displays, users can select and display any combination of data outputs (navigation and engine control systems, for example) at any position. The results are great, especially considering N2K makes it easier for boat builders to plan and install electronics systems during construction and for owners to install aftermarket equipment.
Given that all N2K-compliant gear can communicate with other such gear, boat owners can purchase and install equipment based on options and functionality they like, rather than manufacturer compatibility with existing equipment. Not only can all N2K equipment communicate, it does it around 52 times faster than with NMEA 0183 (250,000 bits per second vs. 4,800).
How it Works
The CliffsNotes version is that N2K is a bi-directional multitransmitter/multireceiver instrument network that uses a single wire — or “backbone” cable — running the length of vessel to interconnect electronic equipment. Sensors and displays are attached using a series of T-shaped connectors. A good analogy would be a power cable serving a string of homes along a rural highway. Each home taps into that single cable as it passes by, rather than having individual lines leading back to the powerplant.
Each piece of electronics plugs into the backbone cable using a standardized waterproof connector and a section of “drop cable,” the length of which can be adjusted as required. Additional T connectors can also be added anywhere along the length of the backbone cable, greatly simplifying future installations and expansion of the system. It’s also easier to remove damaged equipment for repair or connect a laptop to the system for troubleshooting.
Connections are made using CAN (controller area network) Bus technology, the same system used in the automotive industry. CAN functionality is instantaneous, and the cable carries data, power, and ground, so power draw and installation hassles are reduced (thanks to universal cabling, color codes, connectors and plugs). With N2K, the end result is a robust installation infrastructure that is not only neater and more efficient but also less costly to install, maintain and upgrade.
What it Shall Be
Bluetooth is a low-power, device-todevice wireless system that can be used to connect electronics within a limited range of each other (typically 30 to 40 feet). You’ve probably used it to sync your smartphone to a remote speaker or your boat’s stereo system. Wi-Fi can be used for device-to-device connections, too, and it allows one to network multiple devices via a local- or wide-area network (LAN or WAN). It has a typical range of around 350 feet, though this can be increased via the use of booster antennas.
Both Bluetooth and wireless systems transmit radio waves at the 2.4 GHz frequency, which is the same as your home phone’s wireless handset. However, one key difference between the two is bandwidth, which is the amount of data bits able to be streamed per second. The bandwidth for Bluetooth is 800,000 bits per second, compared to Wi-Fi’s capability of 11 million bits per second.
Wi-Fi also brings the possibility of Internet access to the table, when it’s connected to a suitable WAN (though use of the term Wi-Fi does not necessarily mean Internet connectivity when used to describe connectivity between onboard marine electronics). Many manufacturers use basic Wi-Fi technology to connect various components of the electronic suites they offer — multifunction displays being a good example — or to enable remote control and display via other wireless equipment such as tablets or phones. A major benefit here, of course, is the ability to connect an iPad or other such tablet, loaded with an appropriate app, and easily create a remote secondary station.
So, while N2K has revolutionized data and power-cable installations, does wireless technology mean cable itself is poised to go the way of 8-track tapes? Physical connectivity is safe for the moment; however, it’s a sure bet we’ll continue to see advancements in wireless technology that will snip the wires to more and more marine electronics.