Speed Optimization Tool

Speed Optimization Tool for Marine Voyages

The Speed Optimization Tool helps ship operators, engineers, and chartering teams determine the optimal vessel speed that minimizes overall voyage cost. It balances fuel consumption against time-related costs using a physics-based power model and realistic operational inputs. This makes it suitable for slow steaming analysis, charter party planning, and operational efficiency studies.

What the tool calculates

For each candidate speed within the selected range, the calculator evaluates:

• Voyage time from distance and speed
• Main engine power using a scaling law (P ∝ Vⁿ)
• Total power demand including sea margin and auxiliary load
• Fuel consumption using SFOC
• Fuel cost from fuel price
• Time cost from daily operational or charter cost
• Total cost = fuel cost + time cost

The result is a full cost–speed curve, from which the tool identifies both the cost-optimal speed and the fuel-optimal speed.

Underlying model & assumptions

The exponent n typically lies between 2.7 and 3.5 for displacement vessels, with n ≈ 3 commonly used as a first approximation. You may adjust it to reflect hull form, loading condition, or empirical trial data.

Cost-optimal vs fuel-optimal speed

This tool deliberately distinguishes between two important operational speeds:

• Fuel-optimal speed: The speed that minimizes total fuel consumption, usually the lowest practical speed.
• Cost-optimal speed: The speed that minimizes total cost, where higher fuel burn may be justified by reduced voyage duration and lower time-based costs.

In tramp and time-charter operations, the cost-optimal speed is often more relevant than the fuel-optimal one. In liner or emission-constrained operations, fuel-optimal or emission-optimal speeds may take priority.

How to use the Speed Optimization Tool

1. Enter the voyage distance and economic parameters (fuel price, time cost, currency).
2. Define the reference speed and power, SFOC, sea margin, and auxiliary load.
3. Select a realistic speed range and step size.
4. Run the optimization to generate the cost curve and optimal speeds.
5. Export the result as PNG or PDF for reporting or comparison.

Typical use cases

Limitations & good practice

• This is a steady-state model; acceleration, currents, and heavy weather effects are not explicitly modeled.
• Results depend strongly on SFOC and time cost—use realistic values.
• Use consistent assumptions when comparing multiple voyages or vessels.
• For regulatory work, combine this tool with emissions and efficiency indicators such as EEOI or CII.

Related calculators

The Speed Optimization Tool is most powerful when used together with the following calculators:

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