Marine And Boat Acronyms And Abbreviations

When a reader wrote in a while back complaining that the many initials, abbreviations, and acronyms in electronics articles nowadays leaves him baffled, we set about clearing things up.

Below is a list of acronyms we've been guilty of using in the past. If there are other marine abbreviations you need an explanation for, or some you think we should include, email us and we'll do our best to answer or get them on the list. Magazine@BoatUS.com

ACR: An automatic charge relay is a one-way gate for voltage that allows the second battery in a system to be charged when the motor is feeding the system via the alternator without having to select "both" on your battery selector switch.

AIS: Automatic Identification System (displays real-time ship and marine traffic positions). For more on AIS see, "Collision Avoidance 2.0".

APP: Not strictly an acronym, but shorthand for application (for mobile phones and tablets). Download the free BoatUS App.

AWA: Anchor Watch Alarm

CPA: Closest Point of Approach, the predicted minimum distance between your vessel and a target on radar or AIS if you both continue at present course and speed

DSC: Digital Selective Calling (allows a distress signal to be sent from a VHF)

DSM: Digital Sounder Module, also called a black box in some cases, a microprocessor dedicated to interpreting and improving sonar displays on your fishfinder

EBL: Electronic Bearing Line, bearing to a target as displayed on a radar screen OR Exposed Location Buoy if you're talking aids to navigation

EPIRB: Emergency Position Indicating Radio Beacon (used to alert services in an emergency)

IP: Internet Protocol, just a name for how devices speak to each other

LED: Short for Light Emitting Diode, a form of semiconductor that gives off light when an electrical current is applied. Far more efficient than incandescent bulbs, they also have a longer lifespan (when fed proper voltage) because there's no filament to break or burn up. For more on LED lighting for your boat see, "Let There Be LEDs".

LCD: Liquid crystal display, just another way of making images appear on a screen

MFD: Multifunction display. Your chartplotter, can do more than show you charts, hence the "multi" part

MFI: Depending on where you see it, it could be Made for Apple (iPhone, iPad, etc) or Multi-port fuel injection, if you're talking engines

MMSI: Maritime Mobile Service Identity (the number that identifies your boat. Important in an emergency. Register your MMSI number here.

MOB: Man Overboard

NMEA: National Marine Electronics Association

PLB: Personal Locator Beacon (portable transmitter capable of sending an emergency distress signal)

RTE: Route, in shorthand, or Radar Target Enhancer if you are being fancy with your radar reflector

VHF: Very High Frequency, the designation for the frequency bandwidth that marine radios operate on. Specifically from 156-163 MHz. Distinct from UHF (Ultra High Frequency) where cordless phones and baby monitors work

VRM: Variable Range Marker, the rings on a radar display that indicate distances from your vessel at the center.