# Bunkering Decisions: Port Calls That Can Move

> A 2025 study shows bulk carriers can profit from deviating to cheaper bunker ports. What that means for suppliers, agents and how to win the stem early.

URL: https://vesselreach.si/blog/bunkering-decisions-port-calls-that-can-move | Published: 2026-11-06 | Industry news | Topic: Segment playbooks (bunkering)

## In short

Bunker buyers can now treat a port call as optional. A 2025 study in the Journal of Marine Science and Technology found that bulk carriers allowed to deviate from their route to bunker where fuel is cheaper beat ships restricted to bunkering only at load or discharge ports. For bunker suppliers and port agents, every stem must be won before the ETA is fixed.

## Key takeaways

- A 2025 Journal of Marine Science and Technology study modelled handysize bulk carriers in East and South Asia and found route deviation for bunkering beat fixed load or discharge port bunkering.
- The study's cost model counted daily running costs, port charges and surcharges alongside the fuel price, so a landed cost quote compares better than a headline fuel price.
- Bunker suppliers should quote early and show full cost, while port agents should track expected arrivals and contact the operator before fixing a PDA.
- Ship chandlers can bundle stores quotes with the bunker call window, and repair yards can pitch a small repair or dry-dock slot as part of the deviation.
- Faster port clearance, including IMO Maritime Single Window work, makes short deviation calls cheaper and widens the ports a ship can use for a stem.

## At a glance

- **What: What did the 2025 study find about bunkering decisions?** Models that allow bulk carriers to deviate to cheaper bunker ports produced better cost performance than models that forced bunkering at load or discharge ports. ([Journal of marine science and technology (National Taiwan Ocean University)](https://doi.org/10.51400/2709-6998.2774))
- **Who: Who operated the vessels in the study?** A Taipei-headquartered operator running handysize ships in East and South Asia provided the real data for the model. ([Journal of marine science and technology (National Taiwan Ocean University)](https://doi.org/10.51400/2709-6998.2774))
- **Where: Where did EPS bunker green ammonia?** In Ulsan, Eastern Pacific Shipping's first very large ammonia carrier took green ammonia from Lotte Fine Chemical. ([Hellenic Shipping News](https://www.hellenicshippingnews.com/eps-dual-fuel-vessel-bunkers-green-ammonia-in-ulsan/))
- **When: When did Petros Panagiotidis move the LPG carrier?** The 5,000 cu m LPG carrier Dream Arrax was moved between two Nasdaq-listed companies for $18m, as reported by Splash247. ([Splash247](https://splash247.com/panagiotidis-moves-another-lpg-carrier-in-18m-fleet-reshuffle/))
- **Why: Why do optional calls matter for suppliers?** When a vessel can deviate to a cheaper bunker port, the stem may never materialise at your port, so suppliers must win the decision before the ETA is fixed. ([Journal of marine science and technology (National Taiwan Ocean University)](https://doi.org/10.51400/2709-6998.2774))
- **How: How is port digitalisation being advanced?** The IMO launched a survey on Maritime Single Windows, and a regional workshop in Accra pushed port digitalisation across nine countries. ([Hellenic Shipping News](https://www.hellenicshippingnews.com/imo-launches-survey-on-maritime-single-windows/))

Bunkering decisions now include the option to deviate. A 2025 study in the Journal of Marine Science and Technology found that bulk carriers can lower total voyage cost by sailing to a cheaper bunker port rather than lifting fuel only at load or discharge ports. For bunker suppliers and port agents, that makes every stem a sales call that must be won before the ETA is fixed.

## What the study found

The paper built a mixed integer linear programming model to choose both the bunkering location and the quantity lifted. It minimised total operating cost, including daily running costs, bunker costs, port charges and surcharges, while respecting time windows at loading and unloading ports ([Journal of Marine Science and Technology](https://doi.org/10.51400/2709-6998.2774)).

The authors tested it on real data from a Taipei-headquartered operator running handysize ships in East and South Asia. Models that allowed route deviation for bunkering produced better cost performance than models that forced bunkering at load or discharge ports ([Journal of Marine Science and Technology](https://doi.org/10.51400/2709-6998.2774)).

Read commercially, the finding is simple. A handysize owner with a stem due in a week is not automatically your customer because your port sits on the route. The stem can move to a neighbouring port if the numbers work.

## Why this week's news sharpens the point

Two stories show how fast the bunker decision set is changing.

In Ulsan, Eastern Pacific Shipping's first very large ammonia carrier took green ammonia from Lotte Fine Chemical, produced at Envision Energy's plant in Chifeng, Inner Mongolia ([Hellenic Shipping News](https://www.hellenicshippingnews.com/eps-dual-fuel-vessel-bunkers-green-ammonia-in-ulsan/)). That is a new fuel, a new supplier relationship and a new port pairing, all decided before the vessel sails.

Meanwhile, Greek owner Petros Panagiotidis moved the 5,000 cu m LPG carrier Dream Arrax between two of his Nasdaq-listed companies for $18m ([Splash247](https://splash247.com/panagiotidis-moves-another-lpg-carrier-in-18m-fleet-reshuffle/)). A change of owning company changes who approves the stem, the credit line and the PDA (the port disbursement account, the agent's cost estimate for a call).

Fleet changes also move tonnage between flags. Oldendorff Carriers reflagged two Capesize bulk carriers to Germany, with Alice Oldendorff transferring from the Portuguese to the German flag at Saldanha Bay ([Hellenic Shipping News](https://www.hellenicshippingnews.com/oldendorff-reflags-two-capesize-vessels-to-germany/)). Flag changes rarely move the bunker port, but they do change the paperwork and the contacts around it.

## The commercial effect by segment

SegmentWhat changesWhat to do before the ETA

Bunker suppliersStems can shift to a cheaper deviation portQuote early and show the full cost, not just the fuel price
Port agentsOptional calls mean a PDA may never be issuedTrack expected arrivals and contact the operator before fixing
Ship chandlersStores orders ride on the bunker callBundle the stores quote with the call window
Repair yardsDeviation can also serve a small repair or dry-dock slotPitch the slot as part of the deviation, not after it

For suppliers, the practical lesson is that price alone does not win the stem. The study's model counts port charges and surcharges alongside the fuel price ([Journal of Marine Science and Technology](https://doi.org/10.51400/2709-6998.2774)). A supplier who can quote a landed cost including agency, port dues and time saved is easier to compare than one quoting a headline number.

## Where the optional calls are being created

Port competition is also reshaping which calls are worth making. Hong Kong is reviewing permit fees for river trade vessels as mainland terminals in Guangzhou and Shenzhen draw cargo away ([The Loadstar](https://theloadstar.com/hong-kong-reviews-river-fees-as-mainland-ports-lure-cargo-away/)). Fee changes at that level shift the economics of a short-sea call, and with it the bunker and stores demand attached to it.

Digital reporting is moving in the same direction. The IMO has launched a survey on Maritime Single Windows, the systems meant to cut a ship's reporting burden ([Hellenic Shipping News](https://www.hellenicshippingnews.com/imo-launches-survey-on-maritime-single-windows/)). Faster clearance makes a short deviation call cheaper to execute, which widens the set of ports a ship can realistically use for a stem.

In West and Central Africa, a regional workshop in Accra organised by the IMO, the Africa Transport Policy Program and the World Bank pushed port digitalisation across nine countries ([Hellenic Shipping News](https://www.hellenicshippingnews.com/advancing-maritime-digitalization-in-west-and-central-africa/)). Suppliers in those ports should expect the same effect over time.

## Who controls the bunker decision on time charter

On a time charter, the charterer usually pays for bunkers and chooses where to lift them, while the owner or technical manager keeps control of the vessel's operations and technical standards. That split means the person who approves the stem may not be the person your sales team first meets. Identify the charterer's operations or bunker desk for the commercial decision, and the owner's technical superintendent for quality and compatibility questions. When the vessel is on a voyage charter, the owner typically controls both. In every case, confirm the DOC holder (the company holding the Document of Compliance under the ISM Code) to know who carries operational responsibility.

## How to work a stem that can move

1. List the vessels expected at your port in the next 7 to 14 days, filtered by type and size.
2. Identify the company that controls the bunker decision, which may be the owner, the technical manager or the charterer.
3. Find the role that approves the stem: operations, procurement or the technical superintendent.
4. Send a cost comparison that includes port charges and time, not just the fuel price.
5. Follow up on WhatsApp or phone while the ETA is still open, then stop if the stem is fixed elsewhere.

That sequence is the same one covered in [bunker supplier lead generation from stems to repeat buyers](https://vesselreach.si/blog/bunker-supplier-lead-generation-stems-to-repeat-buyers), and it matters more when the call is optional. The vessels to watch are the ones whose route passes more than one bunkering option, as in the handysize trades the study modelled ([Journal of Marine Science and Technology](https://doi.org/10.51400/2709-6998.2774)).

## How VesselReach helps

VesselReach turns expected arrivals at your ports into named conversations before the stem is fixed.

- **Vessel intelligence:** see vessels near your ports and scheduled arrivals, which means you can quote while the route is still open.
- **AI company targeting and decision-maker discovery:** identify the company behind each vessel and the operations, procurement or technical roles that approve the stem.
- **Multichannel outreach and follow-ups:** reach them by email, WhatsApp and phone, with staged follow-ups that stop when the stem is fixed or the prospect opts out.

Book a VesselReach demo to see the workflow on your own ports, then test it in the 10-day trial offered after the meeting.

## Key facts

- According to a 2025 study in the Journal of Marine Science and Technology, a mixed integer linear programming model that allowed bulk carriers to deviate from their route for bunkering produced better cost performance than models that restricted bunkering to load or discharge ports (2025). ([Journal of marine science and technology (National Taiwan Ocean University)](https://doi.org/10.51400/2709-6998.2774))
- According to the Journal of Marine Science and Technology, the bunkering optimisation model minimised total operating cost including daily running costs, bunker costs, port charges and surcharges while respecting time windows at loading and unloading ports (2025). ([Journal of marine science and technology (National Taiwan Ocean University)](https://doi.org/10.51400/2709-6998.2774))
- According to the Journal of Marine Science and Technology, the deviation model was tested on real data from a Taipei-headquartered operator running handysize ships in East and South Asia (2025). ([Journal of marine science and technology (National Taiwan Ocean University)](https://doi.org/10.51400/2709-6998.2774))

## Frequently asked questions

### What is a stem in bunkering?

A stem is the bunker fuel order a vessel commits to for a voyage: the quantity, the grade and the port where it will be lifted. Because a ship can now sail to a cheaper bunker port instead of lifting only at load or discharge ports, a stem can move until it is fixed. ([Journal of marine science and technology (National Taiwan Ocean University)](https://doi.org/10.51400/2709-6998.2774))

### Who approves a bunker stem on a time charter?

On a time charter the charterer usually pays for bunkers and chooses where to lift them, so the charterer's operations or bunker desk approves the stem. The owner or technical manager keeps control of vessel operations and technical standards, and the DOC holder confirms who carries operational responsibility.

### What is a port disbursement account?

A port disbursement account, or PDA, is the port agent's cost estimate for a vessel call. When a bunker call is optional and the stem moves to another port, the call may never happen and a PDA may never be issued, so agents should contact the operator before the call is fixed.

### What does the 2025 Journal of Marine Science and Technology study show about bunkering?

The study found that bulk carriers allowed to deviate to a cheaper bunker port can lower total voyage cost compared with forcing bunkering at load or discharge ports. Its model counted daily running costs, bunker costs, port charges and surcharges, and tested real handysize data from East and South Asia. ([Journal of marine science and technology (National Taiwan Ocean University)](https://doi.org/10.51400/2709-6998.2774))

### How can bunker suppliers win a stem when the vessel can deviate to another port?

Bunker suppliers win the stem by quoting early and showing the full landed cost, including port charges and time saved, not just the fuel price. Reaching the charterer's bunker desk or the owner before the ETA is fixed matters more when the call is optional. ([Journal of marine science and technology (National Taiwan Ocean University)](https://doi.org/10.51400/2709-6998.2774))

### How does port digitalisation affect bunker call economics?

Faster clearance through Maritime Single Windows makes a short deviation call cheaper to execute, which widens the set of ports a ship can realistically use for a stem. The IMO has launched a survey on Maritime Single Windows, and a regional workshop in Accra pushed port digitalisation across nine West and Central African countries. ([Hellenic Shipping News](https://www.hellenicshippingnews.com/imo-launches-survey-on-maritime-single-windows/))

## Sources

1. [Khalid Hashim set to pass the baton at Precious Shipping](https://splash247.com/khalid-hashim-set-to-pass-the-baton-at-precious-shipping/), Splash247, 2026-11-06
2. [Hong Kong reviews river fees as mainland ports lure cargo away](https://theloadstar.com/hong-kong-reviews-river-fees-as-mainland-ports-lure-cargo-away/), The Loadstar, 2026-11-06
3. [IMO launches survey on Maritime Single Windows](https://www.hellenicshippingnews.com/imo-launches-survey-on-maritime-single-windows/), Hellenic Shipping News, 2026-11-06
4. [Advancing maritime digitalization in West and Central Africa](https://www.hellenicshippingnews.com/advancing-maritime-digitalization-in-west-and-central-africa/), Hellenic Shipping News, 2026-11-06
5. [Oldendorff Reflags Two Capesize Vessels to Germany](https://www.hellenicshippingnews.com/oldendorff-reflags-two-capesize-vessels-to-germany/), Hellenic Shipping News, 2026-11-06
6. [EPS dual-fuel vessel bunkers green ammonia in Ulsan](https://www.hellenicshippingnews.com/eps-dual-fuel-vessel-bunkers-green-ammonia-in-ulsan/), Hellenic Shipping News, 2026-11-06
7. [Panagiotidis moves another LPG carrier in $18m fleet reshuffle](https://splash247.com/panagiotidis-moves-another-lpg-carrier-in-18m-fleet-reshuffle/), Splash247, 2026-10-26
8. [An Optimization Model for Supporting Bunkering Decisions in Bulk Shipping](https://doi.org/10.51400/2709-6998.2774), Journal of marine science and technology (National Taiwan Ocean University), 2025-01-01

## More on this topic

Bunkering decisions are no longer fixed by geography. A 2025 study in the Journal of Marine Science and Technology showed that bulk carriers can profitably deviate from their route to lift fuel where the total cost is lower, counting port charges and time as well as the fuel price. For suppliers and agents, that means an expected arrival is a lead to work before the ETA, not a booking to wait for. New fuels such as green ammonia at Ulsan and fleet reshuffles that change the owning company add more reasons to check who controls the stem. VesselReach finds the vessels due at your ports, identifies the company and the decision-maker, and runs the outreach and follow-up.

What is a stem in bunkering? A stem is the fuel order a vessel commits to for a voyage, and it can move to another port until it is fixed. Who approves a bunker stem? On a time charter the charterer usually pays for bunkers and chooses the port, so the charterer's bunker desk approves it, while the owner or technical manager handles technical standards. What is a port disbursement account? It is the agent's cost estimate for a call, and an optional bunker call may never produce one. VesselReach surfaces expected arrivals and the roles behind them before the ETA is fixed.

The most useful takeaway is that a stem is a decision, not a booking. A 2025 study in the Journal of Marine Science and Technology found that handysize bulk carriers allowed to deviate for bunkering beat ships restricted to load or discharge ports, because the model counted port charges, surcharges and daily running costs alongside the fuel price. So a supplier who quotes a landed cost, and reaches the operator before the ETA is fixed, is easier to compare than one quoting a headline number.

The bunker stem is now a decision made against total cost, not a fixture of the route. The Journal of Marine Science and Technology study modelled handysize bulk carriers in East and South Asia and let them deviate to a cheaper port, counting port charges, surcharges and daily running costs alongside the fuel price. Port agents see the effect first: an optional call may never produce a port disbursement account. New fuel pairings, such as Eastern Pacific Shipping lifting green ammonia from Lotte Fine Chemical in Ulsan, and fleet transfers that change the owning company add further reasons to confirm who approves the stem. VesselReach, built by CatalystIQ, surfaces expected arrivals at your ports and the roles behind them before the estimated time of arrival is fixed.

---

VesselReach, built by CatalystIQ. CatalystIQ Data Classification and Analysis Services, Al Qusais, Dubai, P.O. Box 129882, United Arab Emirates. info@catalystiq.ae, +971 58 599 7894. Book a demo: https://vesselreach.si/#demo. Pricing: contact us for a quote (https://vesselreach.si/pricing).