marine navigation system
Most Marlin readers aren't planning to install their own electronics, but knowing how best to accomplish the task goes a long way toward getting the best technician for it. Regardless of your DIY status, understanding the following topics, and quizzing your prospective installer on them, will help you get a perfect system installation on the first try — a rarity in the marine world.
It seems redundant to suggest that one read the manual first, but hardly anyone does. I confess, I once hooked up a Sonic Hub, Navico’s integrated sound system, into my multifunction display, and it wouldn’t play. I even called customer service, and a representative walked me through the process of activating the MP3 player. The problem was that it had defaulted to a microphone input upon installation — the icon was clearly visible in the status bar, but I didn’t know what it meant. The process was clearly explained in the manual. I was clearly embarrassed.
Any installer worth his salt will map out a system, diagramming what each component is and how it connects to the overall system and the power grid on board. Simrad rightfully boasts that its systems are easy to install — and in a nod to the DIY guy, it provides an installation diagram for each system invoiced. Without this diagram, installations can become convoluted, incomplete and difficult to service later on. It wouldn’t hurt to put a check mark next to each connection as you move along.
Have a professional cut your display panels. You might be skilled at wielding a jigsaw. I am not. When it became apparent that my old electronics suite was nested in holes that were incompatible with the new installation, I priced a starboard panel. Then I remembered a friend who worked with Plexiglas and starboard. I e-mailed my display-unit templates to JW Austin Industries in Florida, where my friend worked, and then mailed the old panels for a complete reference. Two days later, I received perfectly cut panels that were far more precisely done than anything a jigsaw could have managed. The cost was only about $50 more than buying the $50 starboard panel and cutting my own.
Label your lines within six inches of either termination. Most cables for displays and black boxes come clearly labeled now. Some do not. Most companies do not label the NMEA 2000 cables. Power lines are hit-or-miss. You can buy shrink labels, write on them, and then heat-shrink them around the wire near the terminal connections. This saves time when diagnosing future issues.
Use a separate electronics ground bus and power panel. The National Marine Electronics Association (NMEA) and the American Boat and Yacht Council (ABYC) like to use separate panels if the power is run from a source more than 10 feet away. A panel consists of a ground, a power input, and fused or circuit-breaker connections for each load. It’s a much cleaner installation and easier to maintain.
If your boat does not have a house battery specifically for electronics, install one. Today’s electronics are sensitive to voltage fluctuations and work best with an isolated power source. The best installations use a voltage-sensing relay between a starting battery and the alternator. That way, when the starting battery is topped off, the alternator shifts to the house battery.
Your wiring should be tinned wire in order to resist the corrosion that’s inevitable when operating in salt air. Heat-shrink terminals aren’t required by ABYC or NMEA, but when wiring terminals are in the bilge, using a protective coating of heat shrink is a pretty darned good idea. ABYC and NMEA require power and ground terminals to come either as ringed terminals or bent-tipped forks that can’t easily slip past the terminal screw head. VHF radios often use snap connectors. ABYC wants the terminals to withstand at least 6 pounds of pull without coming apart. Use a hand scale or a Boga Grip tool to measure the tension.
Test your voltage supply before connecting your equipment. ABYC standards allow only a 3 percent drop in voltage from the power source to the item getting power. Also, with the power turned off, test both the ground wire for resistance and the power wire. Have someone wiggle terminals while you hold the meter on both ends of the lead. I use a long jumper with alligator clips to span distances.
When pulling wires, use a fiberglass fish tape. It goes through the channels easily and is less likely to scab existing wires. When you pull a wire, leave a nylon fishing line in place to pull the next one. I use weed-eater string. It slips through the tight spaces easily. In today’s crowded wire chases, it’s practically impossible to run electronics cables in isolated areas, but try. And remember, bundling wires reduces amperage, requiring larger wires to deliver the same current.
One detail that’s often overlooked is the looming and fastening of wires. In engine rooms, the wire supports should be made of metal in order to resist melting or long-term decay from heat.
