Marine Electronics

Fish Finders, Depth Sounders and Chart Plotters

Fish finders are essential equipment on fishing boats. They range from simple depth readouts to combination units that can include mapping and navigational functions. Costs go up with features and can get into the thousands of US dollars.

In choosing a fish finder, you will need to decide on a budget. Next, consideration must be made to the different types of display formats. Units come with grayscale (also known as monochrome) or color displays. Display types can be any of several variations of LCD or they can use a CRT. LCD displays are are the same type commonly used on laptop computers. CRT displays use a picture tube similar to a traditional picture tube television display. CRT displays are best suited for a sheltered environment such as an enclosed cabin. The other choices all tend to boost the price, making a compromise inevitable if you have budget restraints.

GPS

GPS units are essential equipment on today's boats. Units range from inexpensive handhelds to full blown chart plotters. Many GPS units have built in mapping or accept digital maps to help the user navigate.

LORAN

LORAN C which is a refinement of earlier LORAN systems. LORAN C is widely misunderstood and does have it's peculiarities. The basic concept uses a radio receiver to determine a vessel's position by determining the time delays or TD's of an array (typically 2) of LORAN stations.

eLORAN

In 2008, the Department of Homeland Security was named Executive Agent for development of a national backup for critical systems used in position, navigation and timing. Enhanced LORAN (eLORAN) has been identified as the primary candidate for this backup. In 2009, the administration of the LORAN-C program will migrate to the National Protection and Programs Directorate of the Department of Homeland Security in preparation for conversion of LORAN-C operations to eLORAN.

VHF Marine Radios

VHF marine radios are essential equipment on a boat. The usable range of a VHF radio system is dependant on several factors including the weather, the boat , the antenna and the health of the radio. The most important part of the system is the antenna. Marine antennas should be mounted as high as practical. Another important quality of an antenna is it's gain.

Gain is rated in decibels or dB. Most experts recommend a quality antenna with 6 a gain of dB for powerboats under 50 ft. The antenna system can be tested by measuring the VSWR of the antenna. The VSWR should be as low as possible, typically 1.5 to 1 or lower on a healthy antenna.

Emergency position indicationg radio beacons (EPIRBs) are part of the SARSAT system. The SARSAT system was developed in a joint effort by the United States, Canada, and France. In the United States, the SARSAT system was developed by NASA. Once the system was functional, its operation was turned over to NOAA where it remains today. Early models used the 121.5/243 MHz frequency. The current standard is 406 MHz and those models allow the unit to be uniquely registered to a user.

The Coast Guard wishes to remind all boaters that beginning January 1, 2007, both 121.5 and 243 MHz Emergency Position Indicating Radio Beacons (EPIRBs) are prohibited from use in both commercial and recreational watercraft in Alaska, and worldwide. Boaters requiring an emergency rescue beacon aboard their vessel must have a digital 406 MHz model.

The January 1, 2007, date to stop using 121.5 MHz EPIRBs is in preparation for the February 1, 2009 deadline when satellite processing of distress signals from all 121.5/243 MHz beacons will terminate. Following this termination date, only the 406 MHz beacons will be detected by the International Cospas-Sarsat Satellite System which provides distress alert and location data for search and rescue operations around the world.

The regulation applies to all Class A, B, and S 121.5/243 MHz EPIRBs. It does not affect 121.5/243 MHz man overboard devices which are designed to work directly with a base alerting unit only and not with the satellite system.