Voyage optimization for charterparty voyages: does it make sense?

Can a voyage still be optimized when the vessel is operating according to charterparty speed and consumption requirements?

The answer is yes.

A charterparty may define the commercial and operational framework for a voyage, but it does not remove the impact of weather, route selection, engine load or daily operational decisions.

Even when the vessel is operating against an agreed consumption target, voyage optimization can help reduce weather exposure, improve achievable speed, provide greater ETA certainty and support a better documented voyage outcome.

What does charterparty optimization mean?

Voyage optimization under charterparty does not mean disregarding the agreed performance terms. It means identifying the safest and most efficient way to operate within them.

Depending on the charterparty and voyage instructions, the analysis may consider:

• Specified speed and consumption
• Daily fuel consumption targets
• Vessel condition and draft
• Weather and sea conditions
• Required or expected arrival time
• Engine load
• Navigational limitations
• Relevant operational restrictions

The objective is to account for the conditions the vessel will actually encounter and determine how the voyage can be completed as efficiently as possible within the agreed framework.

The same consumption does not always produce the same speed

A vessel's achievable speed is affected by wind, waves, swell and currents.

At the same engine load or daily fuel consumption, a vessel sailing through adverse conditions may achieve a considerably lower speed than a vessel operating in more favourable weather. This means that maintaining the same daily consumption throughout a voyage does not automatically produce a predictable ETA.

Route selection remains important. By reducing exposure to adverse conditions, the vessel may be able to maintain a higher achievable speed for the same consumption target. In other circumstances, the vessel may safely reduce speed or engine load without compromising the required arrival time.

The optimum decision depends on the weather, the vessel and the commercial requirements of the voyage.

Why the shortest route may not deliver the best outcome

The shortest geographical route is not necessarily the most efficient route under charterparty. A shorter route exposed to strong headwinds, adverse currents or high waves may result in:

• Increased resistance
• Reduced achievable speed
• Greater fuel consumption
• A less reliable ETA
• Increased weather exposure
• A higher risk of operational disputes

A slightly longer route through more favourable conditions may improve speed performance and deliver a more predictable voyage outcome.

The purpose of optimization is therefore not simply to reduce distance. It is to identify the best route and operating strategy within the vessel's contractual and operational requirements.

Daily optimization provides a more accurate ETA

Weather forecasts change throughout a voyage. The vessel's position, speed, operational instructions and expected arrival conditions may also change. A route and ETA calculated before departure can therefore become outdated as the voyage progresses.

Daily optimization reassesses the remaining voyage using:

• The vessel's latest position
• Updated weather forecasts
• Current voyage progress
• Latest operational instructions
• Remaining fuel and time requirements

The recommended speed can then be calibrated for the expected weather impact. This gives both the vessel and the operations team a clearer view of the weather-corrected ETA and the expected outcome for the remainder of the voyage.

Charterparty optimization supports the master

The purpose of voyage optimization is not to override the master's authority or navigational judgment. It is to provide additional decision support.

The master receives updated information on the expected route, weather conditions, achievable speed and ETA. The shore-based operations team receives a clearer commercial overview of the voyage and the potential consequences of alternative decisions.

Technology performs the extensive route and performance calculations. The master remains in control of the vessel.

"A charterparty sets the operating framework. It does not remove the opportunity to improve the voyage through better routing, weather awareness and daily decision-making."

Martin Hjorth Simonsen, CEO and Co-founder of Optimum Voyage

Understanding voyage underperformance

When a vessel appears to be underperforming, the final numbers alone rarely explain the complete voyage. A thorough voyage analysis should consider:

• Weather encountered
• Direction of wind and waves
• Ocean currents
• Ordered and achieved speed
• Reported fuel consumption
• Vessel condition and draft
• Route sailed
• Operational instructions
• Relevant periods of the voyage

This provides a more complete basis for understanding whether the result was caused by vessel performance, weather exposure, route selection or operational circumstances.

Daily optimization also creates a clearer record of the information available during the voyage and the recommendations provided. This documentation can be valuable when reviewing the voyage or responding to a potential performance claim.

What happens when the vessel overperforms?

Charterparty optimization can also reveal when a vessel is consistently performing better than the specified speed and consumption figures. In that situation, continuing to operate only against the charterparty target may leave additional savings unrealized.

Where the commercial circumstances allow, the operator can consider moving from charterparty-based optimization to minimum-cost optimization. Minimum-cost optimization evaluates the combined cost of fuel and time. It can identify whether a different speed, engine load or arrival time would improve the complete commercial outcome.

The charterparty target can therefore serve as the operating baseline, while voyage optimization identifies whether further value is available.

From contractual compliance to commercial insight

Charterparty voyages are sometimes viewed as having limited optimization potential because the performance parameters have already been agreed. In practice, those parameters do not determine:

• Which weather the vessel will encounter
• How much resistance the vessel will experience
• Which route will produce the most reliable outcome
• How conditions will develop during the voyage
• Whether the vessel is underperforming or overperforming
• Whether a different operating strategy could create additional value

Voyage optimization turns these variables into practical operational and commercial information. It helps the vessel and shore-based team understand not only whether the charterparty requirements are being followed, but how the complete voyage can be improved within those requirements.

Does optimization for charterparty voyages make sense?

Absolutely.

The charterparty defines the framework. Weather and vessel performance determine how the voyage develops within it.

By combining vessel-specific performance, daily weather updates, route selection, speed guidance, ETA analysis and post-voyage documentation, charterparty optimization can support:

• Safer routing
• More reliable arrival planning
• Improved achievable speed
• Controlled fuel consumption
• Greater operational transparency
• Better voyage analysis
• Stronger claims documentation
• Improved commercial outcomes

Charterparty operation and voyage optimization are not competing approaches. Optimization helps the vessel operate more effectively within the charterparty framework.

Every voyage. Optimized.