Aerial view of a tanker's deck and helideck

Key takeaways

  • Identify the delivery mode and location being assessed.
  • Confirm its fit with the vessel's wider call purpose and programme.
  • Recheck services, timing and price when the mode changes.
  • Leave navigation and transfer arrangements to the responsible qualified parties.

Gibraltar's published options are a starting point

Gibraltar Port Authority describes bunker delivery by barge at anchor and the possibility of supply alongside. GPA delivery information

That public information supports an enquiry about the available modes. It does not allocate an anchorage position or berth, confirm a supplier window or establish that the proposed delivery can occur during another activity.

For a current transaction, the accepted mode proposal is not provided; obtain current verified information. Record the authorised location, mode, period and remaining conditions, using the responsible parties' confirmations rather than a generic capability statement.

Begin with the purpose of the call

A vessel stopping solely for fuel may face a different commercial choice from one already alongside for another service. Identify the existing programme before asking which bunker mode appears less expensive.

The relevant comparison should include the extra activities and time created by each feasible proposition. Avoid charging one alternative with the entire cost of an existing visit while treating common expenses as absent from the other.

If the call's main purpose changes, revisit the fuel plan. A mode selected to fit an earlier programme may no longer offer the same practical or economic benefit.

Ask for a complete mode-specific offer

The supplier's response should identify the accepted fuel, quantity, delivery period and included service boundary for the proposed mode. Ask what must be reconfirmed if the vessel's location changes.

A unit-price indication may remain unchanged while the surrounding services differ. Preserve those differences in the total comparison rather than declaring the offers identical because the fuel line matches.

Do not assume that a quote for one mode includes a later switch. Obtain the revised terms and relevant acceptance before treating the changed arrangement as committed.

Establish the usable sequence through qualified confirmation

Ask the vessel, agent, supplier and relevant port-side parties to identify the feasible delivery opportunity within their responsibilities. The commercial desk needs the agreed sequence and conditions, not an independently invented operating plan.

If the proposed supply depends on completion of another activity, record that dependency. If an overlap is assessed as possible, preserve the specific acceptance rather than generalising it to future calls or other products.

The planning summary should identify the remaining decision and its owner. A broad statement that the vessel will bunker in Gibraltar is insufficient when the choice between modes remains unresolved.

Compare the modes through their commercial endpoint

Decision factorAnchor propositionAlongside proposition
LocationSpecific authorised opportunity requiredSpecific accepted berth context required
Call fitAssess additional steps within the programmeAssess fit with the existing alongside purpose
Supplier offerConfirm mode-specific window and inclusionsConfirm any different service boundary
Time consequenceUse the supported complete sequenceInclude any extension of the existing visit
Change exposureAsk what a location revision affectsAsk what a berth or programme revision affects
Final evidenceLink the completed event to the orderPreserve the same traceability for the actual event

The table does not rank the modes universally. It makes the buyer's actual trade-off visible for the particular call.

Fictional case: the berth plan changes after pricing

A fictional vessel is expected to visit Gibraltar alongside for a separate service, and its buyer seeks fuel that can fit the same programme. The supplier provides a conditional alongside proposition.

The other service is later cancelled. The desk does not simply retain the old fuel price and assume the vessel can receive the same supply at anchor. It obtains an assessed anchor proposition and asks the supplier to identify the commercial differences.

The buyer then compares a complete fuel-only call with its current alternatives. The earlier alongside offer remains useful context, but it is not presented as confirmation of the revised arrangement.

Preserve a fallback without promising its availability

Where one mode remains uncertain, ask whether another feasible proposition can be quoted and what deadline governs it. Record the fallback's conditions, including any additional expense or validity limit.

Do not describe the fallback as reserved unless the relevant parties have confirmed that commitment. An alternative that requires a new acceptance cannot be assumed immediately available when the first plan changes.

A clear fallback can still improve decision-making by showing what evidence and commercial response would be needed. Its value depends on being honestly described.

Close the change before issuing the final instruction

The final confirmation should identify the chosen mode, location, fuel scope and window. Retain the superseded proposal so the price or service change can be explained later.

Check the current text and obtain appropriate review where a changed mode affects cancellation, additional charges or other responsibilities. The commercial choice does not itself authorise the vessel's navigation or transfer activity.

Common mistakes

Do not treat anchor and alongside delivery as interchangeable or assume a public capability statement reserves either opportunity. Other errors include carrying service inclusions across modes, ignoring a cancelled main-call purpose and describing a conditional fallback as available. A matched fuel price can conceal a different complete call cost.

Where Zeaclub fits

Zeaclub supports agentic, AI-assisted operations with a human in control.

Zeaclub provides a multi-party shared workspace for owners, charterers, brokers and port agents.

Explore Zeaclub

Visit the Zeaclub website

Educational information only; not legal, financial or trading advice. Contract wording and applicable rules control. Verify current requirements and obtain qualified advice before acting.

Frequently asked questions

Is one delivery mode always less expensive?

No. Compare the complete feasible propositions within the vessel's actual programme.

Can a quoted alongside supply be moved to anchor automatically?

Obtain the relevant assessment and commercial reconfirmation rather than assuming the terms transfer.

Who determines operational feasibility?

The responsible vessel, supplier and port-side parties assess the arrangement within their roles.

What belongs in the mode-confirmation slot?

Record the accepted location, mode, period, source and any remaining condition or fallback limitation.

Primary sources