Estimating MR Voyage Duration Across a Product Delivery Sequence

Overview

Build the estimate around clearly defined milestones and current information from the owner, terminals, and cargo parties. The result should help the distributor understand which commitment changes when a particular assumption moves.

Key takeaways

• Give each receiver a distinct delivery milestone.
• Track the effect of an earlier call on later commitments.
• Separate proposed sequence changes from confirmed programmes.
• Use scenario branches instead of an artificial average itinerary.

Define the sequence before estimating its duration

List the firm loading and discharge calls in the intended order. Identify optional calls separately and state who will decide whether they occur. An estimate cannot reliably support customer commitments if the itinerary itself remains ambiguous.

For each receiver, ask which event matters: arrival, intended receipt, discharge completion, or availability under its own process. Use those definitions consistently. A distribution planner may need a different endpoint from the local agent coordinating the vessel's approach.

At the loading end, record whether every parcel is ready or whether a component remains conditional. The departure assumption should reflect the assembled programme rather than the status of only the largest allocation.

Do not assume that deleting an optional call leaves every other milestone unchanged. Obtain the relevant revised outlook from the owner and receiving channels. The relationship may depend on the current programme, not simply on the distance removed.

Give each input a source and status

The owner's authorised channel supplies the relevant vessel and passage information. The terminal or receiver supplies its own programme. The cargo desk identifies sales and allocation decisions. The schedule coordinator aligns these inputs without claiming authority over the underlying operations.

Label each milestone as actual, forecast, conditional, or awaiting information. This prevents a confirmed first departure from making all later receiving assumptions appear firm. A multi-call itinerary can contain several levels of certainty at the same time.

IMO's Just In Time portal discusses information exchange and common data structures for port-call coordination. Consistent terminology helps teams interpret the same event in the same way. See the IMO portal.

Retain the last update and source for each material input. A freshly circulated schedule may still contain an old receiving assumption, so the document date alone is not sufficient evidence of currency.

Use a sequence sensitivity table

An illustrative qualitative table can show how a change propagates through the programme without inventing port statistics or vessel performance. The aim is to identify decisions, not to simulate technical operations.

Some changes can be absorbed by the existing programme; others can affect several buyers. The coordinator should ask the responsible sources rather than apply the same generic delay to every later milestone.

Where information remains incomplete, show the base sequence and a conditional branch. A single average date between two different itineraries can describe neither realistic outcome and may mislead every receiver.

Communicate impact customer by customer

A useful update identifies the affected parcel and receiver, not just the vessel's overall position. Explain whether the change affects that customer's expected receipt, a later delivery, or the final completion of the programme.

Avoid forwarding every operational message directly to every customer without context. The commercial coordinator should preserve the factual source while explaining the relevant consequence and the status of any revised forecast.

If the sales team wants to make a new commitment, identify which schedule assumptions support it. A receiver may be willing to accept a range, but that agreement should come from the appropriate commercial discussion rather than be assumed by the chartering desk.

Set a review point before each important customer decision. The purpose is to obtain the information that can change the action, such as whether to adjust onward distribution or evaluate another supply arrangement. Routine updates alone may not align with those decision deadlines.

Fictional case: a first-call change reaches the last customer late

A fictional distributor uses an MR tanker to deliver product to several customers. The first receiver changes its programme, and the chartering desk updates the expected first-call completion. The last customer's sales planner continues using the original delivery forecast.

The coordinator rebuilds the schedule with explicit dependencies between calls. The owner supplies a revised outlook for the remaining employment, and each receiver confirms its own programme through the appropriate channel. The last customer's planning milestone is now visible separately from the vessel's final voyage completion.

The distributor communicates the changed assumption and its effect to the affected customer before making further supply promises. Other customers receive only the relevant update rather than an unexplained new final date.

The lesson is that sequence information needs a defined path through the commercial organisation. A correct local update is insufficient if the later customer decision still relies on an obsolete assumption.

Preserve the distinction between forecast and instruction

The itinerary is a commercial planning tool. It should not contain improvised directions about vessel speed, cargo-handling methods, or technical sequencing. Communicate the required customer outcomes and obtain assessments from the responsible professionals.

If the revised forecast no longer fits the sales programme, escalate the mismatch. The cargo desk may need to discuss timing with a receiver, change an allocation, or consider another commercially permitted option. Each response requires its own authority and confirmation.

Keep a history of material revisions. This makes it possible to explain which information was available when a customer commitment was made. It also supports a fair review after the voyage without rewriting the past to match the final outcome.

At completion, examine where the programme lost clarity. If milestone terminology caused confusion, improve definitions. If an optional call was not communicated, improve change control. If the information simply did not exist earlier, record that limitation rather than invent a procedural failure.

Common mistakes

Using one final date for a multi-receiver shipment hides parcel-specific obligations. Another mistake is assuming that the effect of an early call change is identical for every later customer.

Avoid averaging mutually exclusive itineraries into a single apparently precise forecast. Show the decision branches and explain what activates them.

Do not treat a customer-facing forecast as an instruction to the vessel. Operational assessment and commercial promises must remain connected through authorised channels, with their different responsibilities intact.

Where Zeaclub fits

Zeaclub supports agentic, AI-assisted operations with a human in control.

Zeaclub provides a multi-party shared workspace for owners, charterers, brokers and port agents.

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