Boating-Related Abbreviations and Acronyms

What do they all mean?

Edited by Brian Gordon, Last updated: 12/21/2018

When shopping on or while thumbing through one of our periodic sales fliers, have you ever stumbled across an acronym or abbreviation that you did not understand? For example, what does “CARB” mean? OK, for many of us that’s easy—California Air Resources Board, right? What about “GRS” or “HEI”? Are those a bit tougher? For answers, check the list below, which was compiled by Dr. Charles Fuller, who while proofreading various West Marine publications, has made demystifying a plethora of these a personal crusade. Have you seen a boating-related acronym or abbreviation that is not on the list? Please click here to suggest what we need to add.

Abbreviations and Acronyms

ABS acrylonitrile butadiene styrene
ABYC American Boat and Yacht Council
AC alternating current
ACR automatic charging relay
ACU Antenna Control Unit
AGC automotive glass cartridge
AGM absorbent glass mat (battery technology)
AIS automatic identification system
ANSI American National Standards Institute
API American Petroleum Institute
ASA acrylonitrile styrene acrylate (type of plastic)
ASTM American Society for Testing and Materials
ATF automatic transmission fluid
AWG American Wire Gauge
BGAN Broadband Global Area Network
BNC Bayonet Neill-Concelman (coaxial cable connector)
BTW below the waterline
BRP Bombardier Recreational Products
BSP British standard pipe
CAN Controller Area Network
CARB California Air Resources Board
CASE compact air survival equipment
CB captive ball; captive ball bearing (traveler), captive bearing
CCA cold cranking amps
CCR California Code of Regulations
CE Certification Mark (European Economic Area/EEA)
CFC chlorofluorocarbon
CFR Code of Federal Regulations
CG Coast Guard
CHIRP Compressed High-Intensity Radiated Pulse
CNC computer numerical controlled
CNG compressed natural gas
COHb carboxyhemoglobin
CPE copolyester
CPR cardiopulmonary resuscitation
cSt centi-Stoke (measure of viscosity)
D depth
DAR diameter area ratio
dB decibels
DC direct current
DFI direct fuel injection
DIN Deutsches Institut für Normung (German national organization for standardization)
DIY do it yourself
DSC digital selective calling
DOT Department of Transportation
EIRP equivalent isotropically radiated power
ELCI equipment leakage circuit interrupter
ELT emergency locator transmitters
EMI electromagnetic interference
EN ENs, European Standards
EPA Environmental Protection Agency
EPDM ethylene propylene diene monomer (rubber)
EPIRB emergency position indicating radio beacon
ES emergency shutdown
ESP elegant simple product (e.g., Harken Cruising ESP Block)
FAA Federal Aviation Administration
FDA Food and Drug Administration
FDV fuel demand valve
FH flush-head (fasteners), flathead
FHMS flathead machine screw
FIP female iron pipe
FMCW Frequency Modulated Continuous Wave 
FNPS female national pipe straight
FNPT female national pipe thread
FPT female pipe thread
FRS Family Radio Service
FNPS female national pipe straight
GAWR gross axle weight rating
GC(V)W gross combined (vehicle) weight
GCWR gross combination weight rating
GFCI ground-fault circuit interrupter
GHT garden hose thread
GLONASS Global Navigation Satellite System (Russian)
GMDSS Global Maritime Distress Safety System
gph gallons per hour
gpm gallons per minute
GPS global positioning system
GRIB GRIdded Binary, or General Regularly-distributed Information in Binary form
GRS glass-reinforced surface
GTW gross trailer weight
GVW(R) gross vehicle weight (rating)
GWP global warming potential
HD high definition
HDPE high-density polyethylene
HEI high-energy ignition
HELP Heat Escape Lessening Posture
HL high load
HP high performance
HPU hydraulic power unit
IB inboard
IBA Inflatable Boat Association
ID internal diameter
IERCC The GEOS International Emergency Response Coordination Center
IF Intermediate Frequency
IMO International Maritime Organization
IPS In-plane switching
IO inboard/outboard (engines)
IoT the Internet of Things
IP (either) International Protection Marking or Ingress Protection Marking
ISAF International Sailing Federation
ISO International Organization for Standardization
JASO Japanese Automotive Standards Organization
KDF kinetic degradation fluxion
LAT/LON latitude/longitude
LCD liquid-crystal display
LH left hand
LOA length overall
LED light-emitting diode
LP linear polyurethane
LPG liquified petroleum gas
LWL load waterline length
MCA marine cranking amps
MED (European Union) Marine Equipment Directive
MEK methyl ethyl ketone
MEO Medium Earth Orbit
MFP multi-filament polypropylene
MGHT male garden hose thread
MHz megahertz
mil one thousandths of an inch (1/1000in)
MIM multi-satellite interface module
MIP male iron pipe
MMSI Maritime Mobile Service Identity (a unique nine-digit number)
MOB man overboard
MOLLE (pronounced MOLLY) MOdular Lightweight Load-Carrying Equipment
MPS multi-purpose spinnaker
MPT male pipe thread
MRT metal replacement technology
MSA master service agreement
MSD marine sanitation device
MSW modified sine wave
MTC Monitoring, Tracking and Control system
MWL maximum working load
NBR nitrile rubber
NC numerical controlled
NDRS National Distress and Response System
NDZ no discharge zone
NEXRAD Next-Generation Radar
NFB no feed back
NH National Hose
NIOSH National Institute for Occupational Safety and Health
Nm Newton meter (measure of torque)
NMEA National Marine Electronics Association
NMMA National Marine Manufacturers Association
NOAA National Oceanic and Atmospheric Administration
NPSM National Pipe Straight Mechanical
NPTF National Pipe Taper (fuel)
NPS National Pipe Straight
NPT National Pipe Thread, National Pipe Taper
NSF National Sanitation Foundation
OB outboard
OD outer diameter
OE original equipment
OEM original equipment manufacturer
OMC Outboard Marine Corporation (1929–2000)
ORBIT Omnidirectional Rotating Base Installation Technology
OSR Offshore Special Regulations
PBO polybenzoxazole
PE polyethylene
PFD personal floatation device
PLB personal locator beacon
PH precipitation hardening (e.g., 17-4 PH stainless steel)
POAT poly organic acid technology
PPE personal protective equipment
PRV poly reinforced vinyl
PSS Packless Sealing System
PSW pure sine wave
PTFE polytetrafluoroethylene
PTT Push to Talk
PU polyurethane
PVA polyvinyl alcohol
PVC polyvinyl chloride
PWC personal watercraft
RF radio frequency
RFI radio frequency interference
RH right hand, round head
RHMS round head machine screw
RMS root mean square
RTV room temperature vulcanizing (silicone)
SAE Society of Automotive Engineers
SAME Specific Area Message Encoding
SAR Specific Absorption Rate
SBD (Iridium) Short Burst DataSD secure digital
SLT self-leveling tabs
SMS Short Message Service
SOG speed over ground
SOLAS The International Convention for the Safety of Life at Sea
SPOT (French) Satellite Pour l’Observation de la Terre (Satellite for observation of Earth)
SS stainless steel
SSB single-sideband modulation
ST special trailer (tires)
SUP Stand Up Paddle Boarding
SVR sealed valve regulated (batteries)
SYIS Singles Yarn Impregnation System
THD total harmonic distortion
TFT thin film transistor
THV polymer comprised of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride
TPPL thin plate pure lead (batteries)
TN Twisted Nematic
TW tongue weight (trailers)
TWA time weighted average
UHMW ultra-high molecular weight polyethylene
UL underwriters laboratories
ULC ultralight composite (bearing system, Harken)
UN United Nations
UNC united coarse pitch threads
UNEF united extra fine pitch threads
UNF united fine pitch threads
UNS united special threads
USA United States of America
USCG United States Coast Guard
UV ultraviolet
VHF very high frequency
VMG velocity made good
VMS Vessel Monitoring System
WAAS Wide Area Augmentation System
WC weight carrying, water closet (Europe)
WD weight distributing
WEST Wood Epoxy Saturation Technique (West System company)
XD extreme duty
WOT wide open throttle
ZDDP zinc dialkyldithiophosphates