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Marine Electronics

Making Sense Out of NMEA 0183 and NMEA 2000

The NMEA 0183 has two different communication (baud) rates for-4800 baud and the faster 38400 baud (also known as NMEA 0183-HS). You have to match the baud rate of both devices for communication to occur. AIS will always use the faster rate. Once the speeds correlated on our test boat, the radio presented targets on its one-inch display. Sitting at the dock it was apparent that info below decks was useless.

Converters and Connectors Round Out the Expenses

Although wireless systems have gradually made their way aboard modern cruising boats, hard-wiring remains an essential part of most systems, especially when you are matching old and new gear, or using converters. One of the biggest challenge for those of us with terrible fine motor skills is dealing with the tiny wires. Stripping, splicing and connecting these wires isn't neurosurgery, but definitely not the sort of thing you want to deal with on a rocking boat. But like any installation, it is a job you want to get done the first time-especially when you consider the challenges of troubleshooting electronics faults.

Preventing Electric Shock at the Dock

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).

Deck-level Wind Vanes

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.

Crimping and Sealing for a Life Offshore

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.

Special Report: How to Prevent AIS and VHF Antenna Malfunction

Safety of Life at Sea (SOLAS) ships-including tankers, passenger vessels and cargo ships over 300 gross tonnage-must be equipped with Automatic Identification Systems (AIS). In the U.S., carriage requirements also includes vessels over 65-feet. AIS can allow you to see a distant ship, but is not a substitute for radar.

Register Your VHF Radio

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.

Testing VHF Coaxial

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.

Antenna Gain and VHF Transmission Range

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.

Antifouling Paint Prices Follow Copper Surge

The antifouling coating industry is dominated by copper-based paint, so as copper prices reach their highest levels in recent history, I was curious to...