WATERLINE
A line painted on a hull which shows the point to which a ship sinks when it is properly trimmed

WAY
Movement of a ship through water such as headway, sternway or leeway

WCCON
Whether Customs Cleared Or Not

WEATHER PERMITTING
The term used in voyage charter language to signify that laytime does not count when weather conditions do not allow cargo operations to be carried out.
WIBON
Whether In Berth Or Not

WIFPON
Whether In Free Pratique Or Not

WINDWARD
Toward the direction from which the wind is coming

WIPON
Whether In Port Or Not

WLTOHC
Water Line-To-Hatch Coaming

WOG
Without Guarantee

WP
Weather Permitting. That time during which weather prevents working shall not count as laytime

WPD
Weather Permitting Day

WWD
Weather Working Day

WRIC
Wire Rods In Collis

WWR
When, Where Ready

WWWW
Wibon, Wccon, Wifpon, Wipon

YAR
York Antwerp Rules A set of rules, agreed upon and amended at several international conventions, which governs general average, what losses are allowable, who is required to contribute and the method of calculating the loss. Although these rules do not necessarily have the force of law, often they are incorporated into many contracts of carriage by agreement of the parties.

YAW
To swing or steer off course, as when running with a quartering sea

Z
UTC = GMT

ZONE TIME
The local time zone for any longitude, as opposed to and usually expressed as a deviation from Greenwich Mean time (+3, -6 etc.).