© 2026 Observater Surveys and Services Group. All rights reserved.
Observater Surveys and Services Group · Mombasa, Kenya
Bunkers are the largest variable cost on a charter, and every tonne of them can be argued: at delivery, at on-hire, at off-hire, at redelivery, and in the consumption figures in between. One party’s numbers become the record unless independent figures exist. Our bunker surveyors put those figures on your side: every tank sounded, temperatures and densities taken, calibration tables applied, and the arithmetic shown, at the berth, at anchorage by launch, in Mombasa, Lamu, and across East African ports, around the clock. If the stem is tomorrow or the dispute is already running, the second best time to instruct is now.
Get a Bunker Surveyor Moving Email the InstructionA few percent short on a full stem is real money, gone quietly. Short delivery rarely announces itself: it hides in temperature, in foam, in a gauge read generously. Without an independent survey at delivery, the bunker delivery note becomes the truth, and the invoice follows the note.
At redelivery, both sides are certain and one of them is paying. Owner and charterer each hold a figure they believe. The party without an independent sounding record argues from memory against paper. Hire and bunker accounts settle on the record that exists.
Consumption disputes grow in the dark. A vessel that burns more than the charter party says eats the margin voyage after voyage, and the log abstracts alone will not settle whether the cause is the ship, the fuel, or the figures. Unexamined, the overconsumption simply continues.
The supplier surveyed. Did you? If the other side attended the transfer and you did not, the only measured record is theirs, taken by a party paid to protect the sale. Your surveyor puts a second file on the table and tests theirs against the tanks.
Bunkers are most often the single largest drain on a ship’s operating cost, with the power to erase a voyage’s profit for owners and charterers alike. Determining the accurate quantity of bunkers on board at delivery, at redelivery, and at any point in between is what keeps that cost from turning into a dispute, and what wins the dispute when it comes anyway.
The determination is only worth the independence and the discipline behind it, and every step taken in determining the quantity of bunkers on board is taken with care and attention, because a careless reading costs someone real money. Our surveyors work to one standard on every attendance: check and understand the vessel’s general and tank arrangement plans first, sound every tank on the plan, apply measured temperatures and densities, work the calibration tables, and show the arithmetic, so the certified figure can be tested by anyone who needs to test it, including the party who dislikes it.
Attendance runs around the clock at Mombasa and Lamu, at the berth and at anchorage by launch, across East African ports through the group, and at other ports across Africa and beyond, on instruction, with attendance confirmed before work begins.
The delivery is where the money moves and where it goes missing. Our BQS attendance covers both sides of the transfer: the barge or shore tanks gauged before and after, the receiving vessel sounded before and after, meters read where fitted, temperatures taken on both sides, and the two records reconciled on the spot, so a difference is raised while the barge is still alongside instead of in a letter two weeks later.
Attended at the berth and at anchorage by launch, day and night, because stems do not wait for office hours. Experience is applied to uncover the trade tricks that shave a stem: aeration that inflates a sounding, temperatures declared warmer than measured, gauge readings taken at a helpful trim, and tapes that read what the reader wants. Each is checked, and what is found is recorded.
A charter begins and ends with the same two questions: how much fuel is on board, and what condition is the ship in. Answer either one loosely and the argument arrives at redelivery with interest. Our on-hire and off-hire attendances settle both at once: all bunker tanks sounded and quantities certified, and the vessel’s condition recorded compartment by compartment, holds, hatch covers and coamings, decks, and cargo-relevant fittings, with hold cleanliness inspected and reported for the trade intended.
In Mombasa these surveys are most often performed combined, and often jointly: one surveyor appointed by owners, another by charterers, attending together as second or even third parties. We act for either side, or attend jointly with the other party’s surveyor, under the conflict rule that governs everything we do: one interest per matter. Vessel condition, machinery, and certificates are inspected as part of the attendance, with certificates verified current and in use.
Waiting for redelivery to discover a bunker problem is choosing to discover it at the most expensive possible moment. Intermediate bunker inspections put a measured checkpoint in the middle of the charter: tanks sounded, ROB certified, consumption to date reconciled against log abstracts and delivery notes, so a drift between the ship’s figures and the measured figures is caught while it is still small, still explainable, and still correctable.
Charterers use them before sub-letting, owners use them when the noon reports stop adding up, and traders use them whenever fuel on board is part of a deal. One attendance, one certified snapshot, and the rest of the charter runs on a figure both sides watched being taken.
Remaining-on-board is the number that closes the account, and it is argued harder than any other figure in the charter. Our redelivery attendances certify ROB tank by tank, with the same discipline as on-hire, so the final bunker statement reconciles against the first one and the difference is consumption, not confusion.
ROB surveys also stand alone: before dry docking and repairs, before a sale or handover, before a lay-up, and whenever an owner, buyer, financier, or insurer needs the fuel on board fixed as a measured fact rather than a declared one. The certificate states what was sounded, at what temperature, against which tables, and the calculation sheets travel with it. The same surveyors carry out ship pre-purchase surveys and damage inspections, so a buyer’s bunker figure, condition record, and damage picture arrive in one file.
When the delivered figure and the invoiced figure disagree, somebody is paying for fuel that is not in the tanks. Shortage investigation follows the arithmetic to where the missing tonnes went: the barge figures, the vessel figures, the temperatures used on each side, the tables applied, the timing of each reading, and the paper trail between them, until the difference has a cause and the cause has an address.
The investigation works whether we attended the original transfer or not: a late file built from the documents and a fresh sounding still narrows the dispute to its facts. Suppliers instruct us to defend a delivery as often as receivers instruct us to challenge one, one interest per matter.
A vessel that burns more than the charter party warranted is a dispute measured in dollars per day, and it is rarely settled by the log book alone. Our consumption investigations put the whole record on one table: log abstracts, noon reports, bunker delivery notes, sounding records, and performance data, reviewed line by line against a physical survey of the tanks, so the argument runs on reconciled figures rather than rival estimates.
Our bunker surveyors review documents after a dispute has started, audit consumption across a period on standing instruction, and attend physically wherever the vessel is, so an overconsumption claim, a performance claim, or a quiet suspicion gets the same treatment: measured, reconciled, and reported in a form owners, charterers, and their clubs can act on.
Quantity is half the bunker argument; quality is the half that can damage an engine. Our attendances witness sampling at the manifold, seal and label the splits, retain custody records, and route sealed samples to accredited laboratories under chain of custody, with MARPOL sample handling witnessed and recorded. When a quality dispute surfaces weeks later, the sealed retained sample and its unbroken custody record are what make the laboratory result usable.
Barge tank inspections and bunker escort attendances complete the service: the barge gauged and inspected before it comes alongside, and the transfer watched end to end where the stakes justify it.
The vessel’s general and tank arrangement plans are checked first, and every tank on the plan is sounded: bunker tanks, sludge and lube tanks, bilges, cofferdams, and deep tanks in investigative work, so nothing sits uncounted where fuel could sit. Gauges are checked against alteration, gauged tanks are sounded anyway, and our own calibrated temperature instruments and kink-free tapes are used and verified.
Measured temperatures and densities are applied, the vessel’s calibration tables are worked, trim and list corrections made, and the calculation sheets are annexed to the certificate, so the figure can be tested by anyone who needs to test it. Where experience says a figure is being helped along, the trade tricks are checked one by one and the findings recorded.
Our highly trained bunker surveyors carry out all types of bunker surveys in Mombasa and across Kenya: bunker quantity surveys (BQS) at Mombasa Port, at the Kilindini berths and at Mombasa anchorage by launch; on-hire and off-hire bunker and condition surveys at Lamu Port; ROB and redelivery surveys wherever the vessel lies; intermediate bunker surveys mid-charter; bunker shortage investigations and consumption audits after the figures stop agreeing; and sampling and MARPOL attendances on every stem that needs them. Vessels calling Kenyan ports, transiting the coast, or bunkering at anchorage get the same standard from the same surveyors: a bunker surveyor in Mombasa or Lamu is a phone call away, day and night, and the certificate that comes back reads the same wherever it was earned.
On-hire and redelivery protection, consumption audits when noon reports drift, ROB before yard periods and sales, and condition records that close charter arguments before they open.
Independent delivery figures on every stem, intermediate checkpoints mid-charter, and off-hire files that settle the bunker account on measurements rather than negotiation.
A delivery defended is a customer kept: independent attendance that protects a legitimate stem against a challenge, and sampling custody that protects the quality side of the sale.
Bunker and condition attendance for members and assureds, casualty-linked ROB, and consumption investigations reported to the standard adjusters apply.
Pre-purchase bunker verification and ROB certification, so the fuel in the deal is a measured asset, not a represented one.
Late-stage document review and reconciliation in bunker disputes: the file examined, the figures re-run, and the findings stated in a form proceedings can use.
Where we attend
Our bunker surveyors attend at the Port of Mombasa, Kilindini Harbour, and Mombasa anchorage around the clock, at the berth and by launch, and at Lamu Port at Manda Bay for vessels on the northern coast. East African ports are served through the group: Dar es Salaam, Zanzibar, Tanga, and Djibouti through our own companies. At other bunkering ports across Africa and beyond, instructions are taken and attendance is confirmed before work begins, usually within hours. If the stem is somewhere we have not named, ask anyway; reaching the transfer is usually our logistics problem, not yours.
WhatsApp a Bunker Surveyor ops@observater.comA bunker survey is an independent measurement of the fuel on board a ship: every bunker tank is sounded, temperatures and densities are taken, the vessel’s calibration tables are applied, and the quantity is certified in writing, so owners, charterers, and suppliers settle on a measured figure instead of a declared one.
Bunkers are usually the largest variable cost on a charter, and every handover of fuel is a chance for money to go missing quietly. An independent bunker survey fixes the quantity at delivery, on-hire, off-hire, and redelivery, which prevents disputes, and wins them when they come anyway.
A bunker quantity survey measures the fuel actually transferred during bunkering: the barge or shore tanks are gauged before and after, the receiving vessel is sounded before and after, and the two records are reconciled, so a short delivery is caught while the barge is still alongside.
ROB means remaining on board: the measured quantity of fuel in a vessel’s tanks at a given moment. ROB surveys certify that figure at redelivery, before dry docking or repairs, before a sale, and whenever fuel on board must be a measured fact rather than a declared one.
An on-hire bunker survey fixes the fuel quantity and vessel condition at the start of a charter; an off-hire survey does the same at its end. Together they make the bunker account and condition claims settle on measurements taken at both ends rather than on argument.
An intermediate bunker survey is a measured checkpoint taken mid-charter: tanks sounded, ROB certified, and consumption to date reconciled against log abstracts and delivery notes, so a drift between the ship’s figures and the measured figures is caught while it is still small and correctable.
Shipowners and managers at on-hire, redelivery, and yard periods; charterers and operators on every stem and off-hire; bunker suppliers and traders defending deliveries; P&I clubs and insurers on member matters; buyers before a purchase; and lawyers in bunker disputes. One firm serves each, one interest per matter.
Most bunker surveys are completed within a few hours on board, depending on the number of tanks and the operation attended, with figures available on completion and the certificate and calculation sheets following promptly. Attendance in Mombasa and Lamu is confirmed before work begins, usually within hours of instruction.
The attendance line runs 24/7 and stems rarely give notice, so our bunker surveyors work at short notice as standard: who attends, when, and on what basis is confirmed before work begins, usually within hours, at the berth or by launch to the anchorage.
Yes, and in Mombasa joint on-hire and off-hire attendances are common: one surveyor for owners, one for charterers, sounding together. We act for either side under one rule: one interest per matter; if the other side of the same matter calls afterward, they are referred to a different firm.
A bunker survey certificate with quantities by tank, the temperatures and densities applied, and the calculation sheets annexed; condition findings where the attendance includes them; and sampling and custody records where samples are drawn. The arithmetic is shown so the figure can be tested.
Yes. A late file built from the delivery notes, log abstracts, sounding records, and a fresh physical survey still narrows the dispute to its facts. The advantage of early attendance is real, but it has never been the verdict; the argument settles on the better file.
Yes: sampling witnessed at the manifold, sealed splits with custody records, MARPOL sample handling, and sealed samples routed to accredited laboratories, with the custody chain that makes the result stand up.
Soundings, transfers, holds, hatch covers, and samples: the work as it actually looks, from files our bunker surveyors have attended.
The next stem will not wait
Every unattended stem, handover, and redelivery settles on the other party’s figures. Tell us the vessel, the port, and the timing, and our bunker surveyors confirm who attends, when, and on what basis, in writing, before anything starts.
Get a Bunker Surveyor Moving Email the InstructionMarine Surveyors in Mombasa, determined at taking careful measurement of all bunkers onboard/ supplied and condition surveys that examine risks onboard, enabling ship owners and charterers to take sound risk management measures. Safety to the ship, cargo, and seafarers is the first priority in every ship condition survey, with findings reported so clients can remain in compliance with flag and class rules.
Observater Surveys and Services Ltd · HQ: Amir Suites, 1st Floor Room B6, Sauti ya Kenya Road, Mombasa · Tel/WhatsApp +254 776 960 820 · ops@observater.com · All attendances are performed under our standard terms of business, available on request.
The same bunker desk that works Mombasa’s berths and anchorage attends the Port of Lamu and every Kenyan anchorage where fuel changes hands: bunker quantity surveys at the LAPSSET berths, ROB surveys where charters begin and end at Lamu, stem attendance on vessels fuelling on the coast, and sampling sealed and split to the same standard wherever the barge comes alongside. As traffic grows on the northern corridor, the custody questions travel with it — and the desk that answers them is the one already answering at Mombasa, on one instruction line from the head office.
Instructing for Lamu is the same as instructing for Mombasa: name the vessel, the operation, and the time, and the surveyor’s name, scope, and fee come back in writing before attendance — ops@observater.com or WhatsApp +254 776 960 820, answered around the clock.
When precision matters, Observater Surveys Group is your Partner of Choice
© 2026 Observater Surveys and Services Group. All rights reserved.