In the shipping industry, a significant share of the commercial disputes arising under time charter contracts stems from disagreements over bunker quantities and vessel condition at the delivery and redelivery stages.

Accurately determining the fuel on board at the moment the vessel is delivered to the charterer, and formally recording her physical condition, can prevent disputes worth millions of dollars.

For this reason, On-Hire and Off-Hire Bunker & Condition Survey services are widely used around the world by shipowners, charterers, ship operators and P&I representatives.

In this guide, we address in detail the 20 most frequently asked questions about On-Hire / Off-Hire bunker and condition surveys.

What Is an On-Hire Bunker and Condition Survey, and Why Is It Carried Out?

An On-Hire Survey is an independent inspection carried out at the moment the vessel is taken over by the charterer.

Its purpose is to:

Determine the quantity of bunkers on board,
Record the physical condition of the vessel,
Document existing damage,
Establish a reference point before the charter period begins,
Prevent disputes that may arise in the future.

The report produced as a result of this survey is treated as the starting point of the charter period.

What Is an Off-Hire Bunker and Condition Survey, and When Is It Required?

An Off-Hire Survey is the inspection carried out at the end of the charter period, before the vessel is redelivered to the owner.

During this survey:

The remaining bunker quantity is determined,
The condition of the vessel is assessed,
Any damage that occurred during the charter period is identified,
A comparison is made against the condition recorded at delivery.

The Off-Hire Survey is particularly important as a commercial safeguard in time charter contracts.

What Are the Differences Between On-Hire and Off-Hire Surveys?

The fundamental difference lies in their purpose.

On-Hire

Establishes the initial reference.
Records the current condition.

Off-Hire

Provides an assessment at the end of the charter period.
Reveals the changes and damage that have occurred.

When both reports are considered together, the changes that took place over the course of the charter period can be seen clearly.

Why Is a Bunker Survey Important in Time Charter Operations?

Bunker costs are one of the largest items in a vessel’s operating expenses.

An incorrect bunker assessment can lead to:

Fuel cost disputes,
Unjustified payment claims,
Legal proceedings,
Commercial losses.

For this reason, measurements carried out by an independent bunker surveyor provide the parties with a reliable reference.

Which Fuel Measurements Are Taken During an On-Hire Bunker Survey?

During the survey, the following are generally measured:

HFO (Heavy Fuel Oil)
VLSFO (Very Low Sulphur Fuel Oil)
MGO (Marine Gas Oil)
MDO (Marine Diesel Oil)
Lubricating Oils

Based on these measurements, the volume and weight are calculated for each tank.

How Is Fuel Quantity Determined in an Off-Hire Bunker Survey?

The surveyor:

Takes tank sounding measurements,
Checks ullage values,
Measures the fuel temperature,
Uses the tank calibration tables,
Applies density corrections.

The remaining bunker quantity is then calculated using the data obtained.

Which Parts of the Vessel Are Inspected During a Condition Survey?

In condition surveys, the following areas are generally checked:

Hull condition
Deck equipment
Cargo holds
Tanks
Cranes
Hatch covers
Engine room
Accommodation spaces
Navigation equipment
Safety equipment

The aim is to document the current condition objectively.

What Information Should an On-Hire Condition Report Contain?

A high-quality report should include the following information:

Vessel particulars
Survey date
Port details
Fuel quantities
Photographic records
Damage findings
Equipment condition
Surveyor’s observations
Statements of the parties’ representatives

How Does an Off-Hire Survey Report Prevent Potential Disputes?

An Off-Hire report:

Provides objective evidence,
Ensures that damage is documented,
Reduces bunker disputes,
Supports the interpretation of the charter party,
Serves as evidence in insurance processes.

For this reason, it is frequently used as a reference document in legal disputes.

What Commercial Risks Arise from an Incorrect Bunker Assessment?

An incorrect determination of the bunker quantity can lead to serious consequences such as:

Incorrect invoicing,
Overpayment,
Underpayment,
Commercial objections,
Arbitration proceedings,
Legal disputes.

On large-tonnage vessels in particular, even a small percentage of error can result in a significant cost.

How Is a Bunker Survey Carried Out, and Which Methods Are Used?

The bunker survey process generally consists of the following stages:

Review of documents
Verification of tank plans
Sounding measurements
Temperature measurements
Density verification
Calculations
Reporting

This process is conducted in accordance with internationally accepted survey practices.

How Are Fuel Tank Measurements (Tank Sounding) Carried Out?

During the tank sounding operation:

A sounding tape is used,
Tank levels are measured,
The presence of water is checked,
The temperature is recorded,
Calibration tables are used.

This data forms the basis of the tonnage calculation.

What Does a Bunker Surveyor Do, and What Are Their Responsibilities?

A Bunker Surveyor:

Verifies the fuel quantity,
Carries out the measurements,
Performs the calculations,
Prepares an impartial report,
Reduces the risk of commercial disputes.

Their role is to provide an entirely independent and objective assessment.

Why Are Photographic and Video Records Important in a Condition Survey?

Visual records:

Serve as evidence,
Enable damage to be verified,
Are used in dispute resolution,
Provide supporting evidence in court and arbitration proceedings.

A good condition report can contain hundreds of photographs.

How Are On-Hire/Off-Hire Reports Used in Charter Party Disputes?

These reports are used as important technical evidence in:

Damage claims,
Fuel disputes,
Delivery/redelivery processes,
Arbitration files,
Insurance assessments.

Which Documents Are Required for Bunker and Condition Surveys?

The following documents are generally reviewed:

Charter Party
Bunker Declaration
Tank Capacity Tables
Stability Booklet
Noon Reports
Engine Log Book
Oil Record Book
Ship’s certificates

How Long Do On-Hire and Off-Hire Surveys Take, and How Is the Cost Determined?

Factors that affect the duration:

Vessel size
Number of tanks
Port conditions
Fuel types
Scope of the survey

While simple operations may take a few hours, comprehensive inspections can extend beyond a full day.

What Are the Advantages of Using an Independent Surveyor?

Using an independent surveyor:

Ensures impartiality,
Produces a reliable report,
Reduces the risk of disputes,
Supports insurance processes,
Builds trust between the parties.

For this reason, an independent surveyor is preferred in many charter contracts.

What Are the Most Common Mistakes in On-Hire/Off-Hire Surveys?

The most common mistakes are:

Incomplete sounding measurements
Use of the wrong tank tables
Incorrect temperature correction
Missing photographic records
Incorrect bunker calculation
Inadequate reporting

These mistakes can lead to serious commercial consequences.

What Should You Look for When Engaging a Professional On-Hire / Off-Hire Bunker and Condition Survey Service?

When selecting a service provider, the following should be evaluated:

The surveyor’s experience,
Level of technical knowledge,
Familiarity with international practice,
Report quality,
References,
Impartiality,
Capacity for prompt reporting.

Reports prepared by an experienced surveyor play a critical role in preventing potential disputes and protecting commercial rights.

Conclusion

On-Hire and Off-Hire Bunker & Condition Survey services are not merely a technical check in modern shipping operations; they are also one of the fundamental tools of commercial risk management.

Accurately conducted bunker measurements and comprehensive condition assessments can protect shipowners, charterers and ship operators from disputes worth millions of dollars. In time charter operations in particular, independent and professional survey services provide transparency between the parties and help ensure that operations are carried out with confidence.

Orionis Shipping, with its experienced survey team, provides On-Hire / Off-Hire Bunker and Condition Survey services at ports worldwide, offering its clients reliable, impartial technical support in line with international standards.