Abbreviations & Definitions
By letter: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | 0-9
Y/A  York/Antwerp (rules) 
Yacht  A non cargo carrying vessel normally used for Leisure 
Yacht Carrier, semi submersible  A semi submersible heavy load carrier specifically arranged for the carriage of yachts 
YAR  York-Antwerp Rules 
Yard  Shipyard at which vessels are built. 
Yaw  A temporary swing off course by a vessel, usually because of waves, but may be caused by poor steering, currents, or wind. The horizontal angular deviation of a vessel’s longitudinal axis from the desired line of track. The angular, oscillatory motion (rotation) about the ship vertical axis; to alternately swing to and fro off course, usually by wave action (EM 1110-2-1613). 
Yawing  Ship Stability: is when the vessel rotates about the vertical (up-down) axis 
YB  Yellow Book - onboard the ships on management  
YC  Your Cable 
YDAY  Yesterday 
Yield  The quantity andor quality of derivatives a process can make, or actually makes, from a feedstock or raw material. The industry speaks of gasoline yields from CRUDE; ethylene yields from naphtha, VGO yields from long residue, light products yields from cat cracking, and so forth. 
Yield slate  The breakdown of various derivatives from processing a feedstock or raw material. Typical yield slates could list the quantities of various fuels made from a grade of crude in a certain type of refinery, or basic petrochemicals from steam cracking a particular ethylene feedstock. 
YR  Your of Year 
YUGO  Yugoslavia