The Sole Cargo module in Marine Solver is designed for pre-fixture voyage planning where one or several vessels must be matched with available cargo opportunities under real commercial and operational constraints.
The task may look simple when viewed as a single voyage: a vessel is open, several cargoes are available, and one of them has to be selected. In practice, however, the decision is rarely isolated. Choosing one cargo changes the vessel's next position, availability date, future market access, fuel consumption, regulatory exposure, and the feasibility of every cargo that could follow.
For this reason, Sole Cargo does not treat voyage evaluation as a sequence of independent calculations. It considers the complete decision structure simultaneously.
From a Single Voyage to a Voyage Chain
A voyage is not only a movement between a loading and discharge port. It is also a transition from one commercial position to another.
A cargo that looks attractive by itself may leave the vessel in an inconvenient region, create a long ballast leg before the next employment, or make a later cargo impossible because of its laycan. Another cargo may produce a weaker immediate result but create a stronger voyage chain.
Sole Cargo therefore allows planning either a single employment or a sequence of cargoes. The optimization model evaluates how individual decisions interact over the full planning horizon rather than selecting each voyage independently.
One Vessel or Several Vessels at Once
The same logic becomes even more important in multi-vessel planning.
When several vessels compete for the same cargo market, optimizing them one by one can produce a poor fleet-level result. The cargo that appears best for Vessel A may be the only commercially realistic option for Vessel B. Assigning it too early can therefore reduce the quality of the overall deployment.
Marine Solver evaluates vessel and cargo combinations as one optimization problem. The objective is not simply to find a good voyage for every ship, but to identify a stronger allocation for the fleet as a whole.
Commercial Constraints Are Part of the Model
Real chartering decisions are shaped by restrictions that cannot be separated from the economic calculation. Sole Cargo incorporates these conditions directly into the optimization model.
Depending on the task, users can define:
- Laycan windows and planning horizons.
- Strict, deviation-based or flexible timing logic according to the planning objective.
- Safety buffers for arrival planning.
- Fixed cargoes that must remain in the voyage plan.
- Specific vessel-cargo assignments where a particular cargo must be carried by a particular vessel.
- Exclusions and compatibility restrictions between vessels and cargoes.
- Freight basis including per metric ton, per cubic meter and lumpsum structures.
- Exit Point or Exit Region requirements for the end of the planned voyage chain.
These are not filters applied after the calculation. They form part of the feasible decision space itself.
Position Is Part of Commercial Value
Vessel positioning is one of the most important elements of pre-fixture planning.
The economic result of a cargo cannot be separated from the ballast required to reach it, and the value of a completed voyage cannot be separated from the position in which the vessel becomes open afterwards.
This is why Marine Solver includes the vessel's initial open position and can also account for a desired final position or region. The model can therefore evaluate not only the direct economics of employment, but also how the voyage contributes to a broader deployment plan.
Economics, Time and Environmental Exposure in One Calculation
Pre-fixture comparison increasingly requires more than freight income and bunker cost.
Sole Cargo combines commercial, operational and environmental components within the same calculation. These include sailing and port time, fuel consumption, port costs, canal costs and waiting, as well as regulatory and environmental metrics such as EU ETS exposure, CII/AER assessment and FuelEU Maritime planning indicators.
SECA and ECA exposure, fuel choices and voyage geography are reflected in the same voyage structure rather than calculated as a separate environmental layer after the commercial result has already been selected.
This matters because the commercially strongest voyage, the fastest voyage and the voyage with the lowest emissions may be different solutions.
Different Objectives Produce Different Fleet Decisions
There is no universal definition of the best voyage.
One operator may be interested in minimum cost. Another may prioritize profitability. In a tight market, reducing non-productive time may become more important. In another planning context, emissions may be the governing constraint.
Sole Cargo allows the same vessel and cargo set to be evaluated under different optimization objectives, including:
- Minimum operating cost.
- Maximum profitability.
- Minimum non-productive time.
- Minimum emissions.
The resulting voyage chains can be structurally different even though the original market data remains unchanged.
Several Feasible Scenarios Instead of One Black-Box Answer
Commercial shipping decisions rarely reduce to one unquestionable optimum.
Two solutions can be close economically while producing very different vessel positions, time structures or regulatory exposure. A planner may reasonably prefer the second-ranked mathematical solution because it fits a wider commercial strategy better.
For this reason, Marine Solver can return several alternative scenarios rather than presenting one result as the only possible answer. The scenarios can then be compared through voyage timelines, operational breakdowns, financial metrics and environmental indicators.
The purpose is not to hide the decision inside an optimization engine. It is to make the decision space visible.
Pre-Fixture Decision Support, Not Voyage Execution
Sole Cargo is intentionally positioned at the pre-fixture stage.
Its role is to answer questions such as: Which cargo should this vessel take? Which vessel should take this cargo? Is a voyage chain stronger than a single employment? What happens to the rest of the fleet if this opportunity is fixed? Where should the vessel ideally finish the chain?
Detailed voyage execution, exact routing and operational optimization after fixture belong to a different stage. Marine Solver focuses on the commercial decision that comes before them.
Conclusion
Sole Cargo treats voyage planning as a connected optimization problem rather than a collection of individual voyage calculations.
By considering cargo selection, vessel availability, laycan constraints, fleet positioning, voyage chains, costs and environmental exposure within one model, it helps planners evaluate not only whether a voyage works, but whether it is the right voyage within the wider decision structure.
That distinction is important. In pre-fixture planning, the strongest decision is often not the voyage with the best isolated result. It is the voyage that leaves the strongest set of options afterwards.
Explore other Marine Solver planning models:
For multi-parcel and onboard cargo scenarios, see the
Part Cargo Module.
For transportation planning under contractual lifting obligations, explore
COA Cargo Optimization.
For fleet-level transportation program coverage, read about
Trader Fleet.