A quoted number of free days is not a delivery plan until the charge, clock, start event, calendar convention, equipment, location, payer and stop event are all identified.
A window container discharges on Friday before a public holiday. Customs needs a corrected document, the terminal appointment is full and the site cannot receive the glass racks until Tuesday. The team says it has 'seven free days', but nobody knows whether that phrase refers to carrier demurrage, detention, combined free time or terminal storage—or whether weekends count. A useful plan replaces shorthand with separate clocks tied to live tariffs, booking terms and physical events.
1. Separate every clock before counting a day
Create one row for each possible charge rather than one 'port cost' line. Carrier demurrage/detention or a combined product, terminal storage, rail or depot storage, chassis/equipment use, reefer-related charges if relevant, customs examination, documentation and appointment fees can have different owners and clocks. Use the exact labels in the governing shipment documents; do not impose a generic definition where the tariff uses another one.
For every clock, capture the start trigger, time zone, day-count convention, free-time allocation, tier changes, stop event, applicable equipment/location and evidence of each event. Distinguish vessel arrival, discharge, availability, notice, customs release, terminal release, gate-out, delivery, empty gate-in and acceptance of return. A planned date is not proof that an event occurred.
Check the tariff version and commercial basis that apply to the booking. The US Federal Maritime Commission's detention and demurrage rulemaking illustrates that billing, invoice content and incentive principles can be regulated, but it is not a universal tariff or conclusion for another jurisdiction. The live route documents and local advice control.
| Charge/clock | Start event and evidence | Counting rule/free-time field | Rate tiers/currency/tax | Stop event and evidence |
|---|---|---|---|---|
| Carrier demurrage | [exact event/source/time zone] | [calendar/working days; actual allowance] | [live tariff/quotation] | [event/source] |
| Carrier detention | [event/source] | [actual rule] | [live rate] | [empty accepted/event] |
| Combined carrier clock | [event/source] | [actual allocation] | [live rate] | [event/source] |
| Terminal storage | [event/source] | [terminal rule] | [terminal schedule] | [gate-out/event] |
| Other equipment/depot clock | [event/source] | [provider rule] | [provider schedule] | [event/source] |
2. Build a date-and-evidence critical path
Work backward from safe site receipt and empty return. Record vessel schedule uncertainty; discharge and availability; original/document release; import filing; duty/tax or guarantee steps; inspection or hold; terminal and carrier release; appointment; truck and any lifting equipment; route/access approval; unloading slot; product receiving; empty cleaning or condition process if required; depot nomination; return appointment and acceptance. Assign both action owner and evidence owner.
Add calendars, not just durations: destination holidays, customs and broker hours, terminal/depot shifts, appointment release windows, weekend rules, site closures and carrier cut-offs. Then model credible delay scenarios against each independent clock. A buffer is useful only when it sits before a charge trigger the team can influence.
Do not book delivery simply to stop one clock if the site, equipment or safe unloading method is not ready. Moving a container to an uncontrolled yard can exchange a visible terminal charge for detention, storage, extra handling, cargo damage or insurance gaps. Compare the complete authorised alternative.
| Event | Planned window | Actual evidence/time | Prerequisites and owner | Clock/cost consequence |
|---|---|---|---|---|
| Vessel arrival/discharge | [date range] | [source] | Carrier/terminal visibility | [affected clocks] |
| Cargo available | [date] | [notice/system record] | Documents/physical availability | [clock trigger?] |
| Customs/terminal/carrier released | [date] | [three separate records] | Broker/importer/payment | [consequence] |
| Gate-out/site delivery | [slot] | [EIR/gate evidence] | Truck/site/lift/access | [stop/start clocks] |
| Empty return accepted | [slot] | [depot receipt/EIR] | Depot nomination/condition | [clock stop? verify] |
3. Assign action, cash and contractual responsibility separately
For each event and cost, distinguish who performs or books the action, who supplies information, who pays the invoice initially, who bears cost under the signed arrangement, and who may approve an exception or mitigation. Incoterms rules address specified tasks, costs and risk between seller and buyer but do not replace carrier, terminal, customs, insurance or site contracts.
Record quote validity, currency, tax treatment, pass-through mark-up if contractually relevant, supporting invoice, dispute channel and approval authority. Never net several invoices into 'delay cost' before reconciling dates, units and responsible shipment. Estimate exposure as a range from live tiered schedules, clearly labelled—not as an accrued fact.
Keep operational mitigation separate from later allocation. The party best placed to obtain a slot or return equipment may need to act without conceding ultimate liability. Only authorised legal/commercial advisers should draft reservations or decide entitlement.
| Event/cost | Action owner | Information owner | Initial payer | Contractual allocation/authority |
|---|---|---|---|---|
| Document/customs release | [party] | [party] | [party] | [signed source/review] |
| Terminal appointment/storage | [party] | [party] | [party] | [source] |
| Carrier clock invoice | [party] | [party] | [party] | [source] |
| Trucking/redelivery/waiting | [party] | [party] | [party] | [source] |
| Empty return/depot exception | [party] | [party] | [party] | [source] |
4. Run a daily exception board until empty return
Start before arrival and refresh from primary records at a defined cadence. Show each clock's remaining verified allowance, next tier, blockers, evidence freshness, accountable owner and next decision time. Never let a green customs status imply carrier or terminal release; display them independently.
Escalate contradictory records: changed ETA, rolled vessel, unavailable cargo, customs hold, missing original/release, terminal closure, no appointments, port congestion, site refusal, equipment damage, alternate return depot or rejected empty. Record the source and time of every change and preserve the superseded instruction.
Close only after invoices and physical events are reconciled: cargo delivered, container/other equipment accepted at the authorised return point, condition exceptions documented, final carrier/terminal invoices checked against event evidence and open disputes assigned. A gate receipt can be strong event evidence but does not by itself settle charge validity or responsibility.
| Clock/milestone | Verified status and source time | Next deadline/tier | Blocker and owner | Decision/escalation |
|---|---|---|---|---|
| Availability/releases | [independent statuses] | [time] | [blocker/owner] | [action] |
| Terminal appointment | [status] | [time] | [blocker/owner] | [action] |
| Delivery/unloading | [status] | [time] | [blocker/owner] | [action] |
| Empty return | [depot/slot/status] | [time] | [blocker/owner] | [action] |
| Invoice reconciliation | [received/checked] | [time] | [exception owner] | [disposition] |
FAQ
Are demurrage, detention and port storage the same charge?
No universal answer applies. They may be separate or combined and their terminology varies. Identify each live tariff, clock, payer, location and event.
Do weekends and holidays count as free time?
Check the exact day-count convention in the applicable carrier and terminal documents. Never assume calendar or working days.
When does free time start?
Use the stated contractual/tariff trigger and authoritative event evidence. Arrival, discharge, availability and release are not automatically the same time.
Should a container be moved off terminal immediately to avoid storage?
Only after comparing all costs, safety, cargo protection, detention, site readiness, insurance and authorised handling consequences.
Does an Incoterms rule decide who pays every port delay cost?
No. Review the selected rule and named place together with the sales contract, carriage, terminal and other agreements and applicable law.
Continue the project review
Connect this guide with the proposed window and door systems, then review how Cavorlen approaches manufacturing and quality control. When your schedule is ready, send it through the project review form.
Official sources used
US Federal Maritime Commission — Detention and Demurrage ↗IMO — Facilitation (FAL Convention) ↗ICC — Incoterms rules ↗UNCTAD — Review of Maritime Transport ↗World Bank — Container Port Performance Index ↗Related buyer guides
This article is general logistics and procurement education, not carrier, terminal, customs, tax, legal, accounting, freight-forwarding, insurance or contract advice. It does not define demurrage, detention or storage for a particular contract; calculate or quote free time, rates, taxes, fees, liability, damages or savings; determine who must pay; prescribe customs or container-return actions; or state any Cavorlen route, volume, price, service or responsibility. Terminology and charging methods vary. Verify the actual booking, bill of lading or sea waybill, carrier tariff/quotation, terminal schedule, customs status, equipment provider terms, applicable law and authorised professional advice for the shipment.