Freight Planning — Lead Times, Buffers and Shipment Rhythm That Survive a Bad Month

Work backwards from the date the goods must be usable, not the date you would like them to arrive. Add installation or re-work time, then delivery, then customs clearance, then ocean or air transit, then origin collection and consolidation, then production lead time. Then add a contingency buffer sized to the reliability of the lane. For an Asian sea freight lane that typically means placing the order 10 to 14 weeks before you need the goods; for Europe, 14 to 20 weeks.

Enough to absorb one bad event, not one bad day. On a reliable North Asian lane, 7 to 10 days of buffer covers most single failures. On a lane with transhipment — Europe, India, eastern Vietnam — allow 14 to 21 days. During peak season, or where a biosecurity inspection is likely because of the commodity, increase it. If the consequence of being late is a markdown or a stopped production line, buffer generously; that buffer is cheaper than the consequence.

In rough order of frequency: the supplier ships late; documents are incomplete or inconsistent; the vessel is rolled to a later sailing; funds for duty, GST and charges are not ready when the vessel berths; the container is directed for a biosecurity or customs examination; and no delivery slot was booked before release. Only one of those is genuinely outside anyone’s control.

Balance freight cost per unit against inventory holding cost and the risk of a stock-out or markdown. Larger, less frequent shipments lower the unit freight cost but tie up working capital and concentrate risk. More frequent shipments cost more per unit but reduce both. If your product is seasonal or perishable, or if a stock-out costs a customer relationship, err towards more frequent. Calculate it rather than inheriting it.

Usually safety stock, because sea freight is dramatically cheaper than air freight and warehousing is cheaper than either freight premium. The exception is high value per kilogram goods, where holding stock ties up more capital than the air freight premium costs, and critical spares, where the cost of downtime dwarfs both. The right answer is often a mix: sea freight the bulk into local warehousing, with air freight reserved for genuine exceptions.

A roll-over is when the carrier does not load your container on the booked vessel, usually because the ship is full or the terminal cut-off was missed. It typically costs a week. You cannot prevent it, but you reduce the risk by booking earlier, avoiding the last sailing before a peak or a factory shutdown, ensuring cargo and documents are ready well before the cut-off, and not routing through congested transhipment hubs when a direct service exists.

Assume a factory closure of one to three weeks, plus reduced output for two weeks before as workers leave and two to four weeks after as staff return and quality stabilises. Practically, treat it as a six to eight week disruption rather than a two week holiday. Cargo needed in the first quarter should be produced and shipped well before the closure, and space should be booked early because everyone else is trying to ship before it too.

Per unit of freight, yes. In total cost, frequently no. Shipping less often increases inventory holding cost, increases working capital tied up in stock on the water, increases obsolescence and markdown risk, and concentrates your exposure so that a single delayed shipment becomes a stock-out. Freight cost per unit is the easiest number to see and rarely the most important one.