Ballast is the water that is taken on when a
vessel is empty or partly loaded to increase draft to
properly submerge the propeller and maintain stability,
trim and list.
Clingage is the cargo that adheres to all
surfaces of the emptied portion of the tank other than
Crude Oil Washing ( Go to Tank Washing)
Cargo Quantity Option Certificate is a certificate signed by the vessel and shore
representatives acknowledging the amount of cargo
intended to be loaded. Generally, most product
cargoes have a tolerance based on either supplier,
receiver or vessel capabilities. Each party
involved with the loading shall agree to the quantity to
Draft is the depth of a vessel below the water
line measured from the surface of the water to the
bottom of vessel's keel. The draft can be taken at
six positions (forward, amidships, aft - port and
starboard side). Deviations from measured and
calculated figures usually relate to deviations in the
known constant and hog/stress.
Free Water (FW) is the volume of sea water (or other water contamination) that is in
a container that is not in suspension in the contained
liquid (oil). See also definitions for sediment
Gross Observed Volume (GOV) (Go to Volumes)
Gross Standard Volume (GSV) (Go to Volumes)
Gross Observed Weight (GSW) is the total weight of all petroleum liquids and
sediment and water (if any), excluding free water, as
determined by applying the appropriate weight conversion
factors to the gross standard volume.
Indicated Volume (Go to Volumes)
Inerting is a procedure used to reduce the oxygen
content of a vessel's cargo spaces to 8 percent or less
by volume by introducing an inert gas such as nitrogen,
carbon dioxide or a mixture of gases such as boiler /
inert gas generator flue gas.
Innage gauge (dip sounding) is the measured distance from the surface of the liquid
to a fixed datum plate or to the bottom of the tank.
Letter of Protest (Notice of Apparent
Discrepancy) is a letter issued by any participant in
a custody transfer citing any or all the conditions of
dispute. This letter serves as a written record
that the particular action or finding was questioned at
the time of occurrence. The letter usually has a
paragraph reserving the issuer's right to refer to
matter at a later date.
Liquid volume is the measurable amount of material that is free flowing at the time
List (Heel) is the leaning or inclination of a vessel, expressed in degrees port
or starboard. If found to be other than zero, list
correction tables are to be used to correct the measured
ullage or sounding to compensate for the measured list.
See next paragraph.
List (Heel) correction is the correction applied to the observed gauge or
observed volume when a vessel is listing, provided that
the liquid is in contact with all the bulkheads in the
tank. Correction for list may be made by reference
to the vessel's list correction tables for each
individual tank or by mathematical calculations.
Load on Top is defined as both a procedure and a practice.
Procedure: Load on top is the shipboard procedure
of collecting the settling water and oil mixtures,
resulting from ballasting and tank cleaning operations
(usually in a special slop tank or tanks), and
subsequently loading cargo on top of the slops and
pumping the resultant mixture ashore at the discharge
Practice: Load on top is the act of commingling
onboard quantity with cargo being loaded. The
onboard quantity is the remnant of the previous cargo or
part load into the tank.
Multipoint gauging is the activity of measuring cargo in a vessel tank through two or
more openings in the top of the tank.
Net Standard Volume (NSV) (Go to Volumes)
Net Standard Weight (NSW) is the total weight of all petroleum liquids, excluding
sediment and water and free water, determined by
deducting the S&W weight from the Gross Standard Weight
Non-liquid volume is the measurable amount of material that is not free flowing at the
time of measurement. Non-liquid material may
include anyone or a combination of hydrocarbon waxes,
water/oil emulsions, sediment, or solidified cargo.
On-board quantity (OBQ) (Go to Volumes)