Bunker Surveys in East Africa: A 510+ Vessel Study

Independent bunker quantity assurance across Djibouti, Kenya, Tanzania and Mozambique

Marine fuel is one of the most valuable consumables carried aboard a vessel. A relatively small difference between the quantity declared, physically measured, delivered or remaining on board can materially affect bunker settlements, charter-party accounts, voyage results, supplier reconciliation and subsequent claims.

A bunker survey is therefore more than a set of tank soundings. It is an independent reconciliation of physical quantities, vessel condition, fuel grades, temperature, density, trim, list, tank calibration data, transfers, consumption and documentary evidence at a defined commercial or operational time.

Observater Surveys and Services Group has conducted bunker quantity surveys, bunker delivery surveys, remaining-on-board surveys, on-hire and off-hire bunker surveys, sampling, bunker discrepancy investigations and vessel-performance reviews across the East African coast for several years.

Our regional service coverage includes:

• Djibouti Port and Doraleh;
• Mombasa, Kenya;
• Dar es Salaam, Tanga and Mtwara in Tanzania; and
• Nacala, Beira, Pemba and Maputo in Mozambique.

This publication draws on multi-year operational experience and an anonymized Observater review involving more than 110 vessels. It examines how independent bunker measurements can support commercial settlements while also providing valuable information about vessel consumption, hull condition, maintenance scheduling, machinery reliability and documentary control.

The strongest bunker evidence connects physical quantity, vessel operations, maintenance information and documentary records at one clearly defined moment.

What does an independent bunker survey establish?

A properly conducted bunker survey establishes or verifies the quantity of marine fuel physically present aboard a vessel or transferred during a bunkering operation.

Depending on the appointment, the survey may include:

• bunker quantity surveys;
• bunker delivery surveys;
• on-hire bunker surveys;
• off-hire bunker surveys;
• remaining-on-board surveys;
• delivery and redelivery bunker calculations;
• bunker detective surveys;
• fuel sampling and sample-seal control;
• bunker discrepancy investigations;
• consumption analysis;
• hull and propeller performance reviews; and
• combined bunker and vessel-condition surveys.

The surveyor measures the relevant tanks, records tank temperatures, confirms vessel trim and list, reviews applicable calibration tables and applies the agreed density and correction basis. The resulting quantities are then reconciled with bunker delivery notes, transfer records, engine-room logs, tank movement records and reported consumption.

Where measurements, records or operational events do not reconcile, the survey provides an independent evidence trail for further review.

Why timing matters in a bunker survey

A bunker quantity is only commercially meaningful when it is connected to a clearly defined time.

This is particularly important during:

• vessel delivery or redelivery;
• commencement or completion of charter;
• bunker transfer;
• change of vessel ownership or management;
• voyage completion;
• machinery breakdown;
• bunker consumption dispute;
• suspected short delivery; or
• investigation of an unexplained inventory difference.

A vessel may continue consuming fuel while measurements are being taken. Fuel may also be transferred between storage, settling, service, overflow or drain tanks. Cargo operations, auxiliary engines, boilers, deck machinery and other equipment may remain in operation during the survey.

The appointment should therefore define the contractual or operational cut-off time and explain how consumption and transfers occurring between that time and the physical measurement will be treated.

What our review of more than 510 vessels examined

Observater’s operational review considered more than 510 vessels attended over several years. Repeated attendances aboard feeder vessels created an opportunity to compare the same vessel with itself at different stages of its operating and maintenance cycle.

Where appropriate records were available, our surveyors considered bunker and consumption information alongside:

• vessel speed;
• draft and trim;
• voyage duration;
• operating pattern;
• weather and current;
• auxiliary-engine demand;
• boiler consumption;
• hull-cleaning dates;
• propeller-polishing dates;
• machinery maintenance;
• tank-gauge reliability;
• sounding and calibration information;
• internal tank transfers;
• engine-room orderliness; and
• the completeness of bunker and maintenance records.

The vessel-specific approach was important. Different vessels have different hull forms, engines, coatings, propellers, trading patterns, power requirements and maintenance histories. The most dependable performance comparison is therefore usually between the same vessel’s present and previous operating data under sufficiently comparable conditions.

Hull cleanliness and fuel consumption

A vessel’s underwater hull and propeller must overcome hydrodynamic resistance. Marine growth, surface roughness and propeller fouling can increase resistance and alter the power required to maintain a particular speed.

Across suitable repeated-vessel attendances, post-cleaning voyages frequently provided a stronger operating baseline. As the operating cycle continued, some vessels showed gradual consumption drift that became more meaningful when considered alongside hull-cleaning dates, propeller condition and other maintenance events.

The commercial relevance is significant. Increased consumption may initially appear to be:

• an ROB measurement problem;
• a bunker shortage;
• inaccurate engine-room records;
• excessive consumption;
• adverse weather;
• machinery inefficiency; or
• deterioration in hull and propeller performance.

A physical bunker survey answers the inventory question. A wider consumption and vessel-performance review helps determine which technical or operational factors deserve further investigation.

A useful performance assessment compares:

1. the vessel’s operating data before cleaning;
2. the first suitable voyages following hull cleaning;
3. subsequent voyages as the operating cycle develops; and
4. the next maintenance or cleaning event.

The information should be normalized as far as practicable for speed, draft, trim, weather, current, voyage duration and machinery demand. The resulting vessel-specific direction provides technical managers with a stronger basis for assessing cleaning results and planning the next intervention.

Maintenance scheduling and bunker reliability

Planned maintenance affects more than machinery availability. It also influences the reliability of bunker measurements and consumption records.

Sounding equipment, remote gauges, temperature sensors, valves, pumps, alarms, tank-identification systems and record-keeping processes all depend on effective maintenance.

Our surveyors have found value in comparing bunker and consumption information with maintenance events such as:

• hull cleaning;
• propeller polishing;
• dry-docking;
• coating repair;
• main-engine overhaul;
• turbocharger cleaning;
• fuel-injector maintenance;
• purifier maintenance;
• economizer and boiler maintenance;
• flow-meter calibration;
• tank-gauge calibration;
• speed-log maintenance; and
• changes in fuel-treatment procedures.

When maintenance dates are recorded against consumption data, technical managers can identify whether a performance change followed a particular intervention. Without those dates, a chart may show that consumption changed without explaining why.

Tidiness, housekeeping and evidence quality

A tidy engine room does not, by itself, prove that bunker figures are accurate. Physical measurements, calculations and supporting records remain necessary.

However, orderly machinery spaces and bunker stations can strengthen the measurement process. Clearly identified tanks, accessible sounding points, clean measuring equipment, labelled sample bottles and organized records reduce the possibility of avoidable errors and delays.

The practical question is not whether a vessel appears generally tidy. The relevant question is whether the physical or documentary condition affected:

• access to a tank;
• identification of a sounding point;
• cleanliness of measuring equipment;
• integrity of a sample;
• availability of correction data;
• tracking of internal transfers; or
• timely reconciliation of the final figures.

This connection provides vessel managers with an actionable control finding while keeping the survey focused on observable evidence.

Djibouti bunker survey case study: an additional 46.601 MT identified

In a recent bunker survey at Djibouti Port, Observater’s independent measurement and reconciliation identified additional quantities of:

• +35.729 MT of VLSFO;
• +10.872 MT of LSMGO;
• producing a combined difference of +46.601 MT.

The commercial importance of the attendance was not limited to the numerical difference. Independent verification materially changed the quantity evidence available to the parties.

The survey demonstrated the importance of:

• measuring every relevant bunker tank;
• separating different fuel grades;
• confirming temperature and density inputs;
• reviewing trim and list;
• using the correct tank calibration data;
• establishing the condition of service and settling tanks;
• recording consumption during the survey window;
• reviewing internal transfers; and
• reconciling the physical findings before documentation is finalized.

A quantity difference does not, on its own, determine misconduct, fault or liability. Establishing the cause may require further review of tank movements, earlier measurements, consumption, calibration data and supporting records.

What the survey provided was a stronger independently supported quantity position for commercial reconciliation and any subsequent investigation.

Bunker surveys at Djibouti Port and Doraleh

Djibouti occupies an important position on the shipping route connecting the Red Sea, Gulf of Aden and Indian Ocean. Its operations also support the Ethiopia–Djibouti trade corridor.

Bunker survey appointments at Djibouti Port and Doraleh may involve vessels alongside, at anchorage or operating within tightly controlled port schedules. Effective attendance depends on early coordination with the vessel, agent and relevant operational parties.

The survey scope should confirm:

• vessel location;
• expected boarding arrangements;
• survey time;
• fuel grades;
• nominated or declared quantities;
• transfer method;
• tank plan;
• access requirements; and
• whether the supplying side will also be measured.

Observater provides bunker quantity surveys, on-hire and off-hire ROB surveys, sampling, condition surveys, cargo surveys and claims support in Djibouti.

Bunker surveys at Mombasa, Kenya

Mombasa is a major East African gateway serving a wide range of vessel and cargo operations. Bunker survey attendance may need to be coordinated with cargo work, terminal activity, stores, pilotage, sailing schedules and other simultaneous operations.

The strongest protection is achieved when the surveyor is nominated before the supplier arrives or before the contractual delivery or redelivery time.

For bunker surveys at Mombasa, our recurring measurement priorities include:

• verifying the complete tank list;
• recording port and auxiliary consumption;
• checking internal tank transfers;
• confirming line clearing;
• separating cargo and bunker event times;
• preserving sample and seal records; and
• issuing preliminary figures promptly where sailing time is limited.

Bunker surveys in Tanzania

Observater coordinates bunker and charter survey attendance at Dar es Salaam, Tanga and Mtwara.

Dar es Salaam

At Dar es Salaam, survey planning should account for vessel schedule, berth operations and simultaneous cargo or technical activities. A clear written purpose helps distinguish a delivery survey, ROB survey, charter survey or consumption investigation.

Tanga

Early coordination is particularly valuable where local deployment, launch arrangements or anchorage attendance may be required. The opening measurement baseline should be preserved before transfers, consumption or tank changes alter the physical condition.

Mtwara

Mtwara may involve vessels with project, offshore, construction or specialized operating profiles. Main-engine status, auxiliaries, boilers, deck machinery and other significant fuel consumers should be recorded where they affect the survey interval.

Bunker surveys in Mozambique

Observater provides bunker-survey coverage at Nacala, Beira, Pemba and Maputo.

Nacala

Appointments benefit from early notice, clear access arrangements and confirmation of whether the survey covers the receiving vessel, supplying unit or both. Trim, grade segregation and tank movements require careful treatment.

Beira

Vessel schedules, boarding information and operational timing should be kept current. Stable final measurements, correct temperature and density inputs, documented line clearing and prompt notification of unresolved differences strengthen the evidence.

Pemba

Offshore-support and project vessels may have variable operating loads and frequent internal transfers. The survey scope should identify the vessel’s operational mode and the equipment expected to consume fuel during the survey window.

Maputo

The transfer location, supplying unit, product grade and delivery arrangement should be reconfirmed for every call. Where several grades are carried, tank allocation, density inputs and segregation require particular attention.

Who benefits from independent bunker surveys?

Shipowners and vessel managers

Independent surveys help owners and managers establish physical inventory, verify delivery, monitor repeated discrepancies and connect bunker records with maintenance and vessel-performance information.

Charterers

On-hire and off-hire ROB surveys provide evidence at the contractual transition. They also help distinguish physical inventory differences from consumption occurring between the contractual time and actual measurement.

Bunker buyers and traders

Delivery oversight protects quantity records, sample evidence, transfer chronology and subsequent reconciliation with suppliers.

Bunker suppliers

An impartial survey can document that the transfer was independently measured, sampled and reconciled using an agreed procedure.

P&I Clubs, insurers and claims teams

Early attendance preserves measurements, samples, photographs, logs, signed reservations and other contemporaneous evidence before tanks are used, mixed or transferred.

Technical and efficiency managers

Repeated ROB checkpoints can strengthen consumption analysis, maintenance assessment, hull-performance review and the underlying vessel-data chain.

When should a bunker surveyor be appointed?

The surveyor should be appointed before the bunker transfer begins or before the contractual delivery or redelivery event.

Early nomination allows sufficient time to obtain:

• vessel and agent details;
• tank tables;
• bunker plan;
• expected quantities;
• fuel grades;
• density information;
• sampling instructions;
• contractual survey time;
• access arrangements; and
• reporting requirements.

Late attendance may prevent the surveyor from independently verifying the opening condition.

Information required to appoint Observater

To arrange a bunker survey, provide:

• vessel name and IMO number;
• vessel type and flag;
• port, berth or anchorage;
• ETA and expected survey time;
• agent’s contact details;
• required survey type;
• contractual delivery or redelivery time;
• fuel grades and expected quantities;
• transfer method;
• supplier or bunker-barge details;
• sampling requirements;
• parties to be copied;
• preliminary-report deadline; and
• any known access, discrepancy or protest concern.

Download the complete white paper

The complete Observater white paper includes the detailed 110+ vessel review, bunker measurement methodology, stakeholder guidance, regional port-planning matrix, survey-readiness checklist, service matrix, FAQs and technical references.

Download: Bunker Surveys on the East African Coast — Complete White Paper

Appoint Observater for a bunker survey

Observater Surveys and Services Group provides independent bunker surveys, marine surveys, cargo inspections, vessel-condition surveys and claims support across the East African coast and wider African region.

For urgent attendance, send the vessel name, port, ETA, agent’s details and required survey type.

Website: https://observater.com
Regional operations: surveys@observater.com
Operations support: ops@observater.com
Group operations telephone: +254 776 960 820
Djibouti telephone: +253 77 19 65 48
Djibouti information: Observater Djibouti

Observater Surveys and Services Group
Independent Bunker Surveyors, Marine Surveyors, Cargo Inspectors and Claims Specialists