Speed and consumption claims: how performance disputes are won and lost

Atlas Claims InsightsPublished 27 October 2026 · 8 min read

Speed and consumption claims are among the most common disputes under time charters, and among the most technical. A charterer who believes the vessel was slow or used too much fuel will want to deduct the cost from hire. An owner will point to weather, currents, orders and fouling. Both sides usually rely on experts. Knowing how the claim is built makes it easier to settle on sensible terms.

The performance warranty

Time charters such as the NYPE forms usually describe the vessel as capable of a certain speed on a certain daily consumption, often in laden and ballast conditions and sometimes at several speeds, for example “about 13.5 knots on about 28 mt VLSFO, in good weather conditions”. The questions to answer first are:

• When does the warranty apply? Some descriptions apply only at delivery. Others are continuing warranties that apply throughout the charter. The wording decides.
• Is it qualified? Words such as “about”, “without guarantee” or “WOG” reduce or remove the owners’ commitment.
• What counts as good weather? Many charters define it, for example by reference to a maximum Beaufort wind force and Douglas sea state, and exclude adverse currents.
• Which fuels are covered? Main engine fuel, auxiliary consumption, boilers and gasoil may be treated separately.

What “about” means

In English arbitration practice, “about” has commonly been read as allowing a margin of around 0.5 knot on speed and 5% on consumption. This is a guide rather than a rule of law: tribunals look at the vessel’s type and the charter as a whole, and many charters now state the tolerance expressly or exclude it. Whether the allowance is deducted from the warranted figure before calculating a claim, or only used to decide whether there was a breach, is itself something the charter may address.

How claims are calculated

The usual approach, often called the good-weather method, has three steps.

1. Identify the good-weather periods, usually whole days from noon to noon, in which conditions met the charter definition.
2. Measure performance in those periods: the distance sailed, the time taken and the fuel consumed.
3. Compare with the warranty: the time the vessel should have taken at the warranted speed, less any allowance, and the fuel it should have used, plus any allowance.

The time lost is usually valued at the hire rate and the excess fuel at the bunker price. Tribunals have often accepted that good-weather performance is a fair guide to performance throughout the passage, so the results are commonly extrapolated to the whole voyage, pro rata to steaming time. Whether the allowed fuel is measured over the actual good-weather time or over the time the vessel should have taken can change the figure, and is a frequent point of argument. Our speed and consumption claim calculator shows the effect of each approach.

The evidence

• Noon reports and deck logs from the vessel, giving position, distance, speed, consumption, weather and sea state.
• Weather routing or performance reports from independent providers, usually based on satellite, model or hindcast data.
• Engine and fuel data, such as flow meter records, RPM, slip and bunker delivery notes.
• Voyage orders and instructions, including any orders to steam at economical or reduced speed.

Where the ship’s records and the weather routing report disagree, tribunals do not automatically prefer either. They look at which is more reliable on the facts, how close the vessel was to the data points, and whether the analysis follows the charter definitions.

Owners’ defences

• Wrong good-weather days: days were included that did not meet the definition, for example because of swell or adverse current.
• Charterers’ orders: the vessel was told to slow steam, to proceed at economical speed, or to arrive at a particular time.
• Hull fouling caused by charterers’ trading: long periods idle in warm waters can foul the hull and reduce performance. Many charters now allocate this risk expressly, for example through BIMCO’s hull fouling clauses.
• Bunker quality: off-specification fuel supplied by charterers caused the problem.
• Safety and navigation: the master’s decisions to reduce speed for safety are usually protected.
• Exceptions and off-hire: time that was off-hire, or excluded by the charter, must not be counted twice.

Deductions from hire

Under English law, charterers may in some circumstances deduct a reasonably assessed performance claim from hire by way of equitable set-off. The deduction must be made in good faith and on reasonable grounds. Equitable set-off is clearest for time lost; whether a pure over-consumption claim can be deducted is less settled. An excessive or unsupported deduction may expose charterers to a claim for unpaid hire and, in serious cases, to withdrawal of the vessel. Many charters and their rider clauses limit or regulate deductions, so check them before deducting.

Managing the risk

• Agree clear performance wording, including the definition of good weather and how allowances work.
• Agree in advance which weather routing provider will be used, and how its data will be treated.
• Keep consistent noon reports and record the reasons for any speed changes.
• Raise concerns about performance early, while evidence is fresh, rather than at the end of the charter.
• Consider whether FD&D cover is available for the dispute; see our guide to FD&D cover.

This guide is general information about the law of England and Wales as at October 2026. It is not legal advice and may not cover your situation. Atlas Claims is not a law firm; for advice on your legal rights or on litigation, consult a qualified solicitor.