Evidence Desk - AIS-proven port-call timelines for laytime discussions
The Evidence Desk reconstructs a vessel's port call from her tracked AIS positions and lays it out as a timestamped timeline: when she arrived at the waiting area, when she went alongside, when she sailed. When a demurrage or despatch discussion lands on your desk, the argument is almost always about when things actually happened - and this page gives you an independent, position-based record to hold the paperwork against. It supports the discussion; it does not replace the Statement of Facts, and it is not legal advice.
What the Evidence Desk is
Most laytime disputes are settled on documents the counterparty produced: the agent's Statement of Facts, the terminal's log, the master's notices. The Evidence Desk adds a source none of the parties wrote - the vessel's own tracked movements. From the positions shipdata.net has recorded, it rebuilds the port call as a sequence of observable events: arrival at the anchorage or waiting area, the shift to berth, time alongside, and departure.
That makes it useful in three moments: before you claim (does the timeline actually support the numbers you are about to send?), when a claim arrives (does the counterparty's SOF match what the ship physically did?), and when deciding whether to fight or settle (is the disputed window real, and how well-evidenced is it?).
How to read the timeline
The timeline shows the port call as AIS saw it, oldest event first:
- Anchorage arrival. The moment the vessel stopped in the port's waiting area. In many charterparties this is close to the moment Notice of Readiness could have been tendered, so treat it as a practical proxy for the start of the waiting clock - always subject to your CP's actual wording on when NOR may be given and when laytime starts to count.
- Berth. When the vessel went alongside. The gap between anchorage arrival and berthing is the waiting time - usually the contested part of any demurrage discussion.
- Time alongside. How long the vessel sat at the berth, which brackets the cargo operation.
- Sail. Departure from the port, closing the call.
Each event carries its timestamp and position, so you can check any single line of an SOF against where the ship physically was at that hour.
The confidence badge
Every timeline carries a plain-language confidence badge, and it is there for a reason: AIS coverage is not uniform. Near major ports, receiver density is high and events are pinned tightly; in remote anchorages, crowded radio environments or satellite-only stretches, there can be gaps between received positions, which means an event's true moment sits somewhere inside a window rather than on an exact minute.
The badge tells you, honestly, how tight that window is for this particular call. That honesty is the point. A timeline you present as minute-perfect and cannot defend is worse than no timeline at all - the first gap the counterparty finds discredits the rest. Lead with the well-evidenced events, and treat low-confidence ones as questions to verify against the ship's own records, not as facts to assert.
Queue context: port-wide congestion or vessel-specific delay
A long wait at anchor has two very different explanations, and they lead to very different conversations. If the whole port was backed up, every vessel in the queue waited - the delay is systemic, visible, and easy to corroborate. If the port was moving normally and only your vessel sat, the delay is specific: a terminal issue, a documentation problem, a cargo not ready.
The Evidence Desk shows the queue as it stood when your vessel arrived - how many ships were waiting, and how that compares with what is normal for that port. That single piece of context often reframes the discussion before it hardens into a dispute: a claim that blames the vessel for a wait the entire anchorage shared reads very differently once the queue is on the table.
The laytime calculator: your terms, your browser
Once the timeline is on screen, you can run the numbers against your own fixture. You enter the commercial terms as your charterparty states them - allowed laytime, the demurrage and despatch rates, and how you read the exceptions - and the calculator works the AIS timeline through them to an indicative demurrage or despatch position.
One design decision matters here: everything you type stays in your browser. The terms of your fixture are commercially sensitive, so the calculation runs on your side of the screen and nothing you enter is stored on, or sent to, the server. Close the page and it is gone. The output is a working figure for your negotiation, built on the AIS events - not a formal laytime statement.
Weather windows, where available
Many charterparties count laytime in weather working days, so hours lost to weather can fall outside the clock. Where marine sea-state data is available for the port and the period of the call, the Evidence Desk shows the weather context alongside the timeline - so you can see whether a stretch of the wait coincided with conditions that plausibly stopped work.
Weather context comes from two places. A live archive accrues as ships steam and wait, and for a specific call the desk can also recall historical reanalysis weather for the port and the period of that call, where data allows - so an older call is no longer blank by default. Reanalysis is modelled weather, and the page labels it as indicative rather than observed. Coverage still varies by port and period, and the page says so plainly when no weather context can be shown for a call.
As with everything else on this page, it is context for the discussion: whether a given day actually counted as a weather working day is a matter of the CP wording and the records kept at the port, and certified weather reports govern.
The archive: evidence accrues forward
The Evidence Desk is built from positions shipdata.net has itself recorded, and that history only grows in one direction. Calls that happened after tracking of a vessel began are in the archive and stay there; calls that predate coverage cannot be reconstructed, because there is no free global store of historical AIS to reach back into.
The practical consequence: the archive deepens every day, and the earlier you look, the more of your trade it will already cover. If a fixture looks like it might turn contentious, open the vessel's timeline while the call is happening or soon after - do not wait for the claim to arrive months later.
What this is, and what it is not
Be clear-eyed about the standing of this evidence. The Evidence Desk is supporting evidence: an independent, position-based record that helps you test a claim, prepare questions, and decide your position. It is not a Statement of Facts, it does not replace the master's log, the agent's reports, NOR tenders or terminal tallies, and nothing on the page is legal advice - how events map onto laytime is governed by your charterparty and, where it gets that far, by lawyers and arbitrators.
Used that way, it earns its keep: most demurrage discussions never reach a tribunal, and the side that arrives with a coherent, independently sourced timeline - stated with honest confidence - tends to settle on better terms. Start from the ship page of the vessel in question, and see the ports and congestion guide for the queue data behind the context view.