Abbreviation

Represents

2/M

Second Mate

3/M

Third Mate

AB

Able Seaman

C/M

Chief Mate

COLREGS

International Rules of the Road

FIV

Fishing Industry Vessel

GL

Great Lakes

GL & I

Great Lakes and Inland

GRT

Gross Registered Tonnage

GT

Gross Tons (ITC Tonnage)

INL

Inland

ITC

International Tonnage Convention

LB

Lifeboatman

M

Master

MODU

Mobile Offshore Drilling Unit

MT

Mate

NC

Near Coastal

NMT

Not More Than

O

Oceans

OI

Original Issue

OICNW

Officer in Charge of a Navigational Watch

OIM

Offshore Installation Manager

OSV

Offshore Supply Vessel

RFPNW

Rating Forming Part of a Navigational Watch

RIG

Raise in Grade

ROR

Rules of the Road

ROTWR

Rivers Other Than Western Rivers

STCW

Standards of Training, Certification and Watchkeeping

WR

Western Rivers