TOEIC Link Vocabulary Cluster — Bunker Survey: The Report Lexicon for Determining Fuel Oil Quantity On Board

When a ship takes on fuel, or when it changes hands on a charter, the exact quantity of oil in its tanks becomes a figure worth arguing over. Nobody drains the tanks to weigh the oil; instead a surveyor measures the empty space above the oil in each tank, converts that to a volume, corrects the volume for temperature, and turns the corrected volume into a weight. That indirect, correction-heavy method — the bunker survey — is one of the most report-dense operations in ship husbandry, which is why it recurs as a source domain for TOEIC Link marine and logistics reading passages. The workflow is fixed: the surveyor takes an ullage in each tank, reads the oil temperature, applies the volume correction factor, converts to weight in vacuum, and reconciles the total against the delivery note. That sequence generates a stable cluster of roughly forty terms. A candidate who owns the cluster reads the passage at native speed; a candidate who does not stalls on the load-bearing nouns and loses the passage's argument.

This guide isolates the cluster, groups it by survey stage, and maps each term to its native collocation and register tier, because TOEIC Link scores writing as well as reading. Pair it with the writing vocabulary precision and collocation discipline guide for the skill of choosing the exact term, and with the writing tone and register control guide for matching a term to the formality of the survey report around it.

Why this cluster rewards study

A bunker-survey passage assumes its vocabulary the way a draft-survey or tank-calibration passage does. If a reader decodes ullage, volume correction factor, and weight in vacuum one word at a time, the attention the module intends for the inferential questions is consumed by decoding. Learning the cluster converts those stalls to zero and frees the reader to answer what the passage actually asks — why the surveyed quantity is short of the delivery figure, what the temperature correction depends on, and where the disputed volume lies.

Stage 1 — Gauging the tank

The survey opens with the physical measurement of each fuel tank.

Ullage — the empty distance from the tank top down to the oil surface, the primary gauged figure. Collocation: an ullage is taken at the gauging point; the ullage is read with a tape.
Sounding — the alternative measurement from the tank bottom up to the oil surface. Collocation: a sounding is taken; sounding and ullage sum to the tank depth.
Reference height — the fixed tank depth against which ullage and sounding are checked. Collocation: the reference height is verified before gauging.
Water dip — the check for water beneath the oil using water-finding paste. Collocation: a water dip is taken at the tank bottom; free water is deducted.
Trim and list correction — the adjustment to a gauged figure for the vessel's attitude at the time of survey. Collocation: the ullage is corrected for trim and list.

Stage 2 — From ullage to observed volume

This stage carries the cluster's most discriminating vocabulary — the conversion of a measured depth into a volume the ship's tables can report.

Tank calibration table or sounding table — the ship's book relating ullage or sounding to a volume for each tank. Collocation: the volume is taken from the calibration table.
Observed volume — the raw volume at the tank's actual temperature, before correction. Collocation: the observed volume is read against the ullage.
Trim correction table — the interpolation table adjusting the tabulated volume for the vessel's trim. Collocation: the figure is interpolated for the observed trim.
Gauging point — the fixed reference position at which every ullage is taken. Collocation: the ullage is taken at the marked gauging point.
Free water — water settled below the oil, subtracted to leave the net oil. Collocation: free water is deducted from the observed volume.

Stage 3 — Temperature and density correction

The report converts an observed volume at tank temperature into a standardized quantity, and this is where the arithmetic gets contested.

Oil temperature — the average temperature of the oil in the tank, read at several depths. Collocation: the temperature is measured at upper, middle, and lower levels.
Volume correction factor (VCF) — the factor that reduces the observed volume to the standard 15°C reference. Collocation: the volume is corrected by the VCF.
Standard volume — the volume at 15°C after the VCF is applied. Collocation: the observed volume is reduced to standard volume.
Density at 15°C — the reference density from the bunker delivery note used to convert volume to weight. Collocation: the standard volume is multiplied by the density.
Weight correction factor (WCF) — the factor converting density in air to density in vacuum for the final weight. Collocation: the weight is corrected to vacuum.

Stage 4 — The quantity on board

The survey's deliverable is a weight, and TOEIC Link questions target these terms for procedural inference.

Remaining on board (ROB) — the quantity of fuel already aboard before a delivery. Collocation: the ROB is surveyed before bunkering.
Metric tonnes in vacuum — the standard unit in which bunker quantity is reported. Collocation: the quantity is stated in metric tonnes in vacuum.
Weight in vacuum — the final weight after the WCF, the figure the parties settle on. Collocation: the quantity is expressed as weight in vacuum.
Before and after survey — the two ROB surveys bracketing the delivery, whose difference is the fuel received. Collocation: the delivered quantity is the difference between surveys.
Bunker delivery note (BDN) — the supplier's declared quantity the survey is checked against. Collocation: the surveyed figure is reconciled with the BDN.

Stage 5 — Reconciling and reporting

The survey closes with the comparison and any dispute.

Delivered quantity — the fuel actually received, by survey difference rather than by the supplier's meter. Collocation: the delivered quantity is determined by the before-and-after difference.
Shortage or discrepancy — the gap between the surveyed and the declared quantity. Collocation: a shortage is identified against the BDN.
Cappuccino effect — aerated fuel that inflates the volume and masks a genuine shortage, a term surveyors flag explicitly. Collocation: the cappuccino effect is suspected where readings are unstable.
Letter of protest — the formal note issued when the survey and the BDN diverge. Collocation: a letter of protest is issued over the shortage.
Survey report — the signed statement of ROB, corrections, and reconciled quantity. Collocation: the figures are certified in the survey report.

Register tiers within the cluster

The cluster splits cleanly across the register tiers TOEIC Link rewards a candidate for controlling. Ullage, volume correction factor, weight in vacuum, and remaining on board are high-technical nouns that carry the report's argument and should be produced exactly. Observed volume, free water, and density at 15°C are mid-tier operational terms. Gauged, corrected, and reconciled are the plain verbs any reader must map instantly. A candidate who can move a finding up the register — reporting "the observed volume, reduced to standard by the VCF and converted to weight in vacuum, leaves the delivered quantity short of the bunker delivery note" rather than "there was less fuel than they said" — demonstrates exactly the control the writing module scores.

How to drill the cluster

Read one real bunker-survey report or fuel-quantity survey summary and mark every term above as you meet it; the density will surprise you. Then write a three-sentence determination that (1) states the ullage and the temperature used, (2) names the VCF and the weight in vacuum, and (3) issues the delivered quantity and its agreement with the delivery note. Producing that paragraph from memory is the fastest way to convert a passive reading acquaintance with the cluster into the active control TOEIC Link measures. For the weight-by-displacement counterpart aboard the same vessel, the tank calibration and volumetric strapping survey cluster shares this report's correction vocabulary.

For the writing-side skills this cluster feeds, continue with the writing vocabulary precision and collocation discipline guide and the writing tone and register control guide.