IMO Ship Routeing Measures: A Port Supplier's Guide

IMO ship routing is the set of internationally agreed routeing measures, chiefly traffic separation schemes, that tell vessels which lane to use in busy or constrained waters. When a routeing measure changes, the effect for suppliers is a change in which ports, anchorages and approach channels see calls.

That link between a lane on a chart and a purchase order for fresh provisions or a bunker stem is easy to miss. It is also where a lot of avoidable lost business sits.

What IMO routeing measures actually are

Routeing measures are adopted through the International Maritime Organization and charted so that ships follow an agreed pattern in waters where free routing creates collision risk. The core instruments are traffic separation schemes (TSS), precautionary areas and inshore traffic zones.

A 2024 study in the Journal of ETA Maritime Science modelled a proposed TSS between the Sunda Strait and the Java Sea using the Formal Safety Assessment method. It recommended a traffic separation scheme, a precautionary area with a recommended counterclockwise route and inshore traffic zones, and reported a 54% reduction in collision frequency compared with existing conditions under its preferred option (Journal of ETA Maritime Science).

The study also found that collision frequency remained intolerable even after the improvement, which is a useful reminder: a routeing measure reduces risk, it does not remove the need for careful navigation or for a port to manage its own approach traffic.

Why routeing measures matter to a chandler or bunker supplier

Most of the world's ocean area has no regulated route at all. A 2022 paper in IEEE Access notes that regulated routes such as traffic separation schemes exist in ocean areas adjacent to coasts, while most ocean areas do not have such routes (IEEE Access).

Where a scheme does exist, it concentrates traffic. Ships funnel into a defined lane, a pilot station and usually a single approach channel. That concentration is what makes a port predictable enough to sell into.

The same research shows how analysts reconstruct those lanes from AIS data. A 2020 paper in IEEE Access describes a pipeline that derives maritime traffic patterns from large volumes of AIS vessel tracking data without relying on extra information sources, processing more than a terabyte of non-uniform spatial data in under three hours (IEEE Access).

For a supplier, that is the technical basis for asking a sharper question than "which ships are near me?". The better question is which vessels are being pushed through my approach lane, and when.

What a routeing change does to port calls

A routeing change rarely closes a port. It changes the timing, the approach and sometimes the port of first call, and each of those changes the commercial calendar.

• Arrival windows move. A longer or shorter lane changes ETA accuracy, which changes when a chandler needs stores ready on the quay.
• Anchorages fill differently. Precautionary areas and waiting zones absorb vessels that cannot enter immediately, and anchored ships still buy bunkers, water and spares.
• Port rotation shifts. When a carrier redraws a loop, a port can gain or lose a call outright.
• Husbandry workload changes. Agents see the effect first, in PDA requests, crew changes and last-minute documentation.

The carrier side of that equation is visible in the trade press. According to The Loadstar (October 2026), Gemini Cooperation partners Maersk and Hapag-Lloyd relaunched their Far East-Middle East loop while dropping the Jebel Ali call (The Loadstar).

One dropped call on one loop is a small event. Multiplied across services and seasons, it is the difference between a busy month and a quiet one for every supplier in that port.

Routeing pressure is not only about safety

Commercial and regulatory pressure can redirect traffic in ways no chart shows. British ports have challenged European Union claims that lines are diverting container traffic to the UK to escape carbon charges, with the British Ports Association rejecting findings linking rising UK container activity to ETS avoidance (Splash247, October 2026).

Whatever the merits of that dispute, the operational point stands. A change in effective routing, whether from a TSS, a carbon cost or a carrier decision, moves hulls between ports. Suppliers who track only their own quay learn about it late.

Fuel regulation is another slow-moving routing force. According to MarineLink (October 2026), shippers' appetite for lower-carbon marine fuels weakened this year as the fate of an IMO emissions framework remained cloudy, with some using carbon credits instead (MarineLink).

Bunker demand follows those decisions. A fleet that delays fuel purchases or changes its stem port changes which bunker suppliers get the enquiry.

A practical check for suppliers when a routeing measure changes

Treat a routeing change as a sales event with a checklist, not a notice to file.

1. Confirm the geometry. Which lane, precautionary area or inshore zone changed, and which approach channel feeds your berths?
2. Re-baseline arrival expectations. Watch ETAs for a few weeks rather than assuming the old pattern holds.
3. Map the decision-makers. For each vessel type now using the lane, identify the technical manager, purchasing superintendent and operations contact behind it.
4. Adjust your outreach timing. A vessel on a longer approach gives more notice; a shorter one gives less.
5. Watch the carriers, not only the chart. A loop change can move more cargo than a lane change.

Port calls themselves are the unit to track. As Hellenic Shipping News puts it in its guide to port calls, a port call is a berth booking for a port authority and a service opportunity for a ship agent (Hellenic Shipping News, October 2026).

Where the demand signal shows up first

Newbuild and fleet shifts often reach a port before any routeing notice does. According to MarineLink (October 2026), Anglo-Eastern detailed its role in preparing CMB.TECH's Mineral Europa, a 210,000 dwt Newcastlemax described as the world's first ammonia-powered dry bulk carrier, which has begun its maiden voyage (MarineLink).

Such a vessel needs familiar port services plus fuel and technical support suited to a new fuel. A supplier that knows the ship is coming, and who manages it, gets the first conversation.

How VesselReach helps

VesselReach turns routeing and schedule changes into named conversations before the vessel arrives.

• Vessel intelligence on your chosen ports. VesselReach shows vessels near your selected ports plus scheduled and expected arrivals, which means your team can prepare stores, stems or repair slots while the ship is still on approach.
• AI company targeting and decision-maker discovery. VesselReach identifies the relevant company behind each vessel and finds operations, chartering, procurement and technical superintendent contacts, which means your outreach reaches the person who actually approves the order.
• Staged email, WhatsApp and phone outreach with AI enquiry handling. VesselReach runs personalised sequences across three channels and answers routine enquiries from approved information, escalating to a human on the Android or iOS app when needed, which means fewer missed enquiries during a busy arrival window.

Book a VesselReach demo and see your own ports on the map.