Marine Electronics

The human body runs on electricity and if you overload the nervous system with an external field, everything goes haywire. Every year several people die because they go swimming near a dock, a wiring fault creates an electric field in the water, and their muscles freeze. It is called Electric Shock Drowning (ESD).

Most of us spend a great deal of time away from our boat. Whether shes on the hard, moored in our home harbor or anchored in a foreign port, we want to know whats going on with critical systems. Is my vessel where it should be? Has someone disconnected a power source or tried to gain access? Is the bilge pump cycling more frequently? Is the house bank okay? Is the freezer holding its set-point? If your boat was struck by another vessel, wouldnt it be helpful to have photos?

There are two primary wind indicators on a sailboat. First, we watch the sails. Sailing to windward we watch the jib for luffing and for flow on telltales.

Mast antennas, like all electrical components, are particularly vulnerable to water intrusion at connectors. In the extreme, corrosion at unions or terminals can damage a transmitter.

The U.S. Coast Guard continues be concerned about the misuse (or lack of use) of VHF radios for distress calling. Many boaters, it seems, don't understand the importance of registering their radio equipment, and how to properly use Digital Selective Calling (DSC) feature. Here we offer a brief overview of the most frequently asked questions regarding DSC. More information can be found at the Coast Guards Navigation Center website, www.navcen.uscg.gov.

The loss in RF coaxial cable increases substantially and quickly, when there is water intrusion. Coax that uses foam dielectric, like RG8X and LMR type coax, is particularly prone to this problem because the water can quickly propagate along the foam dielectric used in these type coaxes.

Recreational marine VHF antennas are usually broken down into three categories: 3- and 4-foot sailboat antennas (3dB gain), 8-foot powerboat antennas (6 dB gain) and 16-plus-foot, long-stick antennas (9+ dB gain) that are popular on larger, long-range craft. Antenna gain is a ratio related to an antennas effective radiated power (ERP) instead of a fixed quantitative value.

A typical cruising boat has thousands of electrical connections. The consequence of failure range from a light that doesn't work to a fire that can cost lives.

Regarding the article on recycling gear for cruising in the September 2018 issue, I found that an old Windows laptop, with an external GPS puck and running OziExplorer, makes a fabulous chartplotter. The software is just a hair over $100 and is capable of using NOAA charts, USGS topo maps, aerial photographs, and any other map that can be put in registration, using only latitude and longitude of a couple of points on the map.

Version 1.0.0 of Signal K, the Open Marine Data Standard has now been released, giving developers a stable platform to test and develop new open-source hardware and software for sailors.