BUNKER QUANTITY SURVEY IN SPAIN
Independent bunker fuel measurements and Remaining On Board calculations for commercial vessels.
VALENCIA Marine Services provides independent Bunker Quantity Survey Spain services for shipowners, charterers, operators, managers, and other maritime stakeholders who need an objective determination of fuel quantities on board commercial vessels.
A bunker survey typically involves measuring relevant fuel tanks, reviewing available tank calibration information, applying temperature, density, and vessel-condition corrections, and calculating the Remaining On Board (ROB) quantity at the time of attendance.
Bunker quantity surveys can be performed as an independent service or incorporated into an On-Hire / Off-Hire Survey.
WHAT IS A BUNKER SURVEY?
A bunker quantity survey is an independent measurement and calculation of the fuel quantity in a vessel's bunker tanks at a specified time.
Depending on the assignment, the survey may involve:
tank soundings;
tank ullages;
fuel temperatures;
density information;
tank calibration tables;
vessel trim;
vessel list;
volume corrections;
fuel quantity calculations;
bunker documentation;
Remaining On Board calculations.
WHAT DOES A BUNKER QUANTITY SURVEY INCLUDE?
The exact scope depends on vessel configuration, available documentation and client instructions.
A typical survey may include the following stages.
IDENTIFICATION OF BUNKER TANKS
Relevant tanks may include, depending on vessel configuration:
fuel oil tanks;
marine diesel oil tanks;
marine gas oil tanks;
settling tanks;
service tanks;
storage tanks;
other fuel tanks included within the appointment.
The surveyor establishes which tanks form part of the required calculation.
TANK SOUNDINGS AND ULLAGES
Fuel level measurements are taken using the appropriate sounding or ullage arrangements available on board.
The observed measurement is then compared with the corresponding vessel tank calibration table.
Depending on the tank arrangement, measurements may be obtained using:
sounding tape;
ullage tape;
approved vessel gauging arrangements;
other suitable measurement methods available for the assignment.
Record the measurement method used in the survey documentation.
FUEL TEMPERATURE
Fuel temperature is relevant because the volume of petroleum products varies with temperature.
Where required and practicable, record representative temperatures for the applicable bunker tanks.
Temperature data is used with the relevant density information and correction methodology when calculating bunker quantities.
FUEL DENSITY
Density information may be obtained from relevant available documentation such as:
bunker delivery documentation;
fuel documentation;
laboratory information supplied;
other suitable records made available to the surveyor.
The report should identify the source of the density used for the calculations.
A bunker quantity survey does not automatically determine fuel density through laboratory analysis.
VESSEL TRIM AND LIST
Vessel attitude can affect tank quantities.
Where relevant, calculations may consider:
vessel trim;
vessel list;
applicable tank correction tables;
sounding or ullage corrections.
The methodology depends on the tank tables and information available for the vessel.
TANK CALIBRATION TABLES
Accurate tank calibration information is fundamental to bunker quantity calculations.
The surveyor may use vessel-provided:
sounding tables;
ullage tables;
calibration tables;
trim correction tables;
other relevant tank data.
The calculation depends on the accuracy and applicability of the information supplied for the vessel.
REMAINING ON BOARD — ROB
One of the most common purposes of a bunker survey is to determine the quantity of fuel Remaining On Board (ROB).
ROB quantities may be required for:
vessel delivery;
vessel redelivery;
commencement of charter;
completion of charter;
vessel sale;
commercial disputes;
operational control;
bunker reconciliation.
The survey provides an independent calculation of the bunker quantities determined at the specific time of attendance.
ON-HIRE VS OFF HIRE BUNKER SURVEY
ON-HIRE BUNKER SURVEY
At the commencement of a charter period, bunker quantities may need to be established as part of vessel delivery.
The survey can determine the fuel ROB quantities at the relevant delivery point.
OFF-HIRE BUNKER SURVEY
At redelivery, bunker quantities may again be measured and calculated.
This provides an independent record of the fuel remaining on board at completion of the charter period.
Where earlier bunker data is available, the measurements can be considered within the context of the specific assignment.
BUNKER SURVEY PROCEDURE
1. APPOINTMENT
The client provides:
vessel name;
IMO number;
vessel type;
port;
ETA;
requested survey date;
survey purpose.
2. VESSEL ATTENDANCE
The marine surveyor attends the vessel at the agreed location.
3. DOCUMENT REVIEW
The marine surveyor reviews relevant bunker and tank documentation, where available.
4. . TANK IDENTIFICATION
The tanks included within the survey are identified.
5. SOUNDING OR ULLAGE MEASUREMENTS
Actual observed tank levels are recorded.
6. TEMPERATURE RECORDING
Obtain relevant bunker temperatures where required.
7. VESSEL CONDITION
Consider trim and list where applicable.
8. QUANTITY CALCULATION
Measured levels are converted to volumes using the applicable tank calibration data and corrections.
9. ROB DETERMINATION
The calculated quantities are consolidated into the final Remaining On Board result.
10. REPORTING
A bunker survey report is prepared where included in the appointment.
HOW ARE BUNKER QUANTITIES CALCULATED?
In simplified terms, the calculation process follows:
Observed tank level → tank calibration volume → corrections → corrected volume → density application → calculated fuel mass
The actual procedure depends on:
tank configuration;
calibration tables;
temperature;
density;
trim;
list;
measurement method;
available vessel documentation.
The report should retain sufficient calculation information to make the result technically traceable.
BUNKER SURVEY REPORT
A professional bunker quantity report may include:
vessel name;
IMO number;
vessel type;
port;
date and time of attendance;
appointing party;
purpose of survey;
vessel draft where relevant;
vessel trim;
vessel list;
tank identification;
measured soundings or ullages;
bunker temperatures;
density data;
tank table volumes;
correction data;
individual tank quantities;
total ROB quantities;
documents reviewed;
calculation notes;
survey limitations.
The objective is to provide a clear and auditable record of how the reported quantities were determined.
BUNKER QUANTITY VS BUNKER QUALITY
BUNKER QUANTITY SURVEY
Determines how much fuel is on board.
BUNKER QUALITY ANALYSIS
Determines fuel characteristics through appropriate sampling and laboratory testing.
A standard bunker quantity survey does not automatically include:
fuel sampling;
laboratory analysis;
viscosity analysis;
sulphur testing;
flash-point testing;
water-content testing;
fuel-quality certification.
These require a separate scope when requested.
BUNKER QUANTITY VS BUNKER DELIVERY SURVEY
A bunker ROB survey and a bunker delivery survey are also different assignments.
ROB SURVEY
Determines fuel already present on board at a specific time.
BUNKER DELIVERY SURVEY
Focuses on fuel delivered during a bunkering operation and may require a different measurement and documentation procedure.
The assignment should therefore define precisely which service is required.
MEASUREMENT DISCREPANCIES
Differences in calculated bunker quantities can arise from several technical factors, including:
inaccurate tank calibration data;
vessel trim;
vessel list;
temperature variation;
density information;
sounding measurement;
inaccessible tanks;
tank geometry;
measurement timing;
fuel movement between tanks.
Where relevant discrepancies are observed, they should be documented rather than concealed by adjusting results without technical justification.
BUNKER DOCUMENTATION REVIEW
Relevant documents may include:
tank calibration tables;
bunker delivery notes;
fuel documentation;
previous bunker survey reports;
vessel tank plans;
sounding records;
engine-room records;
density information.
Documentation is reviewed within the limitations of the survey appointment.
SURVEY LIMITATIONS
The accuracy of a bunker quantity calculation depends on several inputs that may be outside the surveyor's direct control.
These can include:
accuracy of tank calibration tables;
accessibility of measuring points;
accuracy of onboard documentation;
vessel movement;
weather conditions;
trim and list;
tank geometry;
fuel condition;
ability to obtain representative temperatures.
The final report should record material limitations affecting the calculation.
WHAT A BUNKER SURVEY DOES NOT AUTOMATICALLY INCLUDE
Unless specifically agreed, the service does not automatically include:
bunker fuel laboratory analysis;
fuel-quality certification;
machinery fuel-consumption analysis;
verification of historical consumption;
flow-meter calibration;
statutory inspection;
Classification Society certification;
determination of contractual liability.
Any additional service should be included expressly in the agreed scope.
BUNKER SURVEY VS DRAFT SURVEY
Both involve technical measurement and calculation, but their objectives differ completely.
BUNKER SURVEY
Determines fuel quantities on board.
DRAFT SURVEY
Determines cargo quantity from the change in vessel displacement.
BUNKER SURVEY AND ON-HIRE / OFF-HIRE SURVEYS
Bunker ROB measurements are frequently carried out together with charter delivery and redelivery inspections.
Where both vessel condition and bunker quantities are required, the assignment can incorporate:
On-Hire condition;
Off-Hire condition;
visible damage documentation;
bunker tank measurements;
ROB calculations.
COMMERCIAL VESSELS
Bunker quantity surveys may be arranged for:
bulk carriers;
general cargo ships;
container vessels;
tankers;
Ro-Ro vessels;
multipurpose ships;
offshore vessels;
support vessels;
other suitable commercial vessels.
The measurement methodology is adapted to the vessel's tank arrangements and available documentation.
BUNKER SURVEY SERVICES AT SPANISH PORTS
VALENCIA Marine Services provides bunker survey attendance at major Spanish commercial ports.
Regular coverage includes:
Valencia • Sagunto • Castellón • Alicante • Cartagena • Tarragona • Barcelona • Algeciras
Other Spanish ports can be considered subject to vessel location, schedule and surveyor availability.
WHY APPOINT VALENCIA MARINE SERVICES
INDEPENDENT MEASUREMENTS
Observed tank measurements are independently recorded during survey attendance.
TRACEABLE CALCULATIONS
Tank data, measurements, and documented calculation inputs support the quantity determination.
COMMERCIAL VESSEL EXPERIENCE
The service is structured for merchant vessels and commercial maritime operations.
NAVAL ARCHITECTURE & MARINE ENGINEERING
The assignment is approached from a technical marine engineering perspective.
CLEAR REPORTING
We present measured data, calculations, and relevant limitations in a structured report.
INTEGRATED SURVEY SERVICES
Where required, bunker surveys can be combined with related On-Hire or Off-Hire vessel inspections.
EXPERIENCED MARINE SURVEYOR
Carlos Montamarta is a Naval Architect & Marine Engineer with more than 20 years of professional experience in marine surveying and ship inspection.
His marine survey assignments combine extensive practical vessel inspection experience with technical expertise in ship structures, marine machinery, marine engineering, technical measurements and professional reporting.
Professional marine surveying services are provided through VALENCIA Marine Services SLU.
INDEPENDENT • DISCREET • PROFESSIONAL
FREQUENTLY ASKED QUESTIONS
WHAT IS A BUNKER SURVEY?
A bunker quantity survey independently measures and calculates the fuel quantity in a commercial vessel's bunker tanks at a specified time.
WHAT DOES ROB MEAN IN A BUNKER SURVEY?
ROB means Remaining On Board and refers to the calculated quantity of bunker fuel remaining on the vessel at the time of survey.
HOW ARE BUNKER QUANTITIES MEASURED?
Tank soundings or ullages are recorded and converted to volume using the vessel's applicable tank calibration tables. Temperature, density, trim, list and other relevant corrections may then be applied.
CAN A BUNKER SURVEY BE INCLUDED IN AN ON-HIRE SURVEY?
Yes. Bunker ROB quantities are frequently determined as part of On-Hire and Off-Hire vessel surveys.
DOES A BUNKER SURVEY INCLUDE ALL FUEL TANKS?
The tanks included depend on the agreed scope and vessel configuration. The relevant bunker tanks should be identified before or during attendance.
IS FUEL QUALITY INCLUDED IN A BUNKER SURVEY?
No. A bunker quantity survey determines fuel quantity. Fuel quality requires appropriate sampling and laboratory analysis under a separate scope.
CAN YOU PERFORM AN OFF-HIRE BUNKER SURVEY?
Yes. Fuel quantities can be measured and calculated at vessel redelivery according to the agreed appointment.
DOES VESSEL TRIM AFFECT BUNKER CALCULATIONS?
It can. Where applicable, consider vessel trim and list using the relevant vessel tank correction information.
DO YOU PROVIDE A BUNKER SURVEY REPORT?
Where reporting is included, the report can document measurements, tank quantities, calculation inputs, total ROB and relevant survey limitations.
CAN YOU ATTEND ON SHORT NOTICE?
Urgent bunker survey attendance can be considered, subject to vessel location, port access, schedule and surveyor availability.
REQUEST A BUNKER SURVEY IN SPAIN
For rapid quotation and attendance, provide:
vessel name;
IMO number;
vessel type;
port;
berth or terminal;
ETA;
expected survey date and time;
On-Hire, Off-Hire or independent bunker survey;
fuel grades to be measured;
relevant client instructions;
required reporting format.
Urgent attendance requests are welcome, subject to surveyor availability.
NEED A MARINE SURVEYOR IN SPAIN?
Independent marine surveying services for shipowners, operators, charterers, insurers and maritime stakeholders throughout Spain.
© 2026 VALENCIA Marine Services SLU · VAT No. ESB06827356 │ Mercantile Registry of Valencia: Volume 11011, Sheet 122, │ Section GNE, Entry 198596
SERVICES
COMMERCIAL VESSELS
CONTACT
VALENCIA Marine Services SLU
Independent marine surveying, vessel inspection, maritime auditing and technical consultancy services for commercial vessels in Spain.
INDEPENDENT • DISCREET • PROFESSIONAL
Marine survey attendance in Spanish ports and shipyards.
Real Club Náutico de Valencia - Camino del Canal 91 - Bloque 3 Local 21 - Valenciac 46024, Spain
Office +34 96 13 050 13
Mobile/WhatsAp: +34 644 70 90 38
Base : Port of Valencia, Spain
Urgent attendance requests are welcome, subject to surveyor availability.