Learn how tanker crews prepare and verify a cargo valve line-up before loading on a tanker ship, coordinate between deck and CCR, establish initial flow, and prevent wrong-tank loading and pressure surge.
A successful tanker loading operation begins before cargo reaches the manifold. The crew must create a clear route from the shore connection to the intended cargo tanks, verify each valve in that route, and make sure the tanks can safely receive the agreed flow.
An incorrect line-up can send cargo to the wrong tank, mix grades, pressurise a closed section of pipe or cause an overflow. A disciplined process brings together the cargo plan, piping diagram, local checks, cargo control room (CCR) indications and clear ship–shore communication.
This article explains the principles behind the valve line-up shown in the training video. The vessel’s approved cargo plan, cargo operations manual and terminal agreement determine its actual valve numbers and operating sequence.
Begin with the loading plan
The chief officer’s plan should identify the cargo grade, receiving tanks, loading sequence, initial and maximum rates, tank-level limits and any restrictions needed for stability, stress or cargo segregation. The team then uses the ship’s cargo line diagram to trace the intended route:
Shore connection → ship’s manifold → cargo main → selected branch lines → designated cargo tanks
Before moving a valve, the operator should understand what that valve connects and what could happen if it is opened or left open. Pay particular attention to crossovers, common lines, pump-room connections where fitted, unused manifolds and connections to tanks carrying another grade.
ISGOTT 6 identifies the setting of cargo lines and valves, valve operation, pressure surges and loading procedures as distinct cargo-operation topics. Its ship–shore checklist also calls for agreed handling procedures and transfer controls. ocimf.org
Assign positions and establish communication
The chief officer or designated loading officer directs the line-up. The CCR operator tracks remote valves, tank levels and alarms. Deck personnel verify the manifold and locally operated valves. A pump-room assignment, if relevant to that ship’s loading route, must follow the vessel’s access and safety procedures.
Everyone needs the same version of the plan. Before the line-up begins, agree on:
- The valve identification system used onboard
- Who may order a valve movement
- Who will operate and independently verify it
- How completion will be reported to the CCR
- How a doubtful position or conflicting indication will be handled
Use closed-loop communication. The person receiving an order repeats the valve identification and requested action; after operating and checking it, they report its actual position. This is especially valuable where similar valve names appear on different tanks or lines.
Example: “Open No. 2 port tank filling valve, tag 2P-14.”
“Opening 2P-14, No. 2 port tank filling valve.”
“2P-14 checked open.”
The example is illustrative; the crew must use its own ship’s valve tags and company communication standard.
Does “zero start” mean closing every valve?
Some training procedures use a zero start or known closed baseline: the team checks that valves in the cargo route are closed before building the planned line-up. This can make an unexpected open crossover easier to find.
It should not be interpreted as a universal order to shut every cargo-system valve on the ship. Some valves serve other active operations or safety functions, and a line must never be left blocked while the terminal is instructed to pump into it. The starting configuration must come from the ship’s approved plan.
A useful zero-start check therefore asks: What is the confirmed status of every valve that could affect this loading route? Record any required exception and resolve unexplained positions before proceeding.
Step-by-step: building the cargo loading line-up
1. Verify the manifold and intended cargo main
Identify the correct manifold connection and cargo grade. Check the connection, unused manifold valves and blanks, containment arrangements, and the line leading from the manifold. Confirm that the designated shore line and ship line match the loading agreement.
The ISGOTT ship–shore checklist includes checks for properly connected manifolds, unused connections, spill equipment and cargo-system sea connections. www.ocimf.org
2. Set segregation and crossovers
Check valves that could divert cargo into another cargo main, another grade’s system or an unintended tank. Their required positions must be verified against the piping diagram. A crossover left open can defeat an otherwise correct set of tank filling valves.
If loading several grades, identify where the systems share pipes or valves and apply the segregation arrangements in the cargo plan. Do not infer separation solely from labels on the CCR display.
3. Open the planned receiving route
Operate the selected tank filling valves in the order specified by the ship’s procedure. One-by-one operation makes each movement easier to identify and verify, but it does not mean starting shore flow with only one tank open in every case. The minimum number of receiving tanks needed at each rate is part of the ship–shore pressure-surge agreement.
After each movement, the operator reports the valve tag and confirmed position. The CCR operator marks progress on the line-up sheet, mimic panel or electronic record used onboard. That mark records a completed check; it does not replace verification of the valve itself.
4. Check tank readiness
Confirm the designated tanks’ current contents and available capacity. Check level indication and high-level alarms, and identify which tank will receive cargo first. Verify the planned tank-atmosphere and venting arrangements. Where inert gas is used, follow the ship’s requirements for atmosphere control and pressure monitoring.
A receiving tank needs both liquid capacity and a suitable route for displaced vapour or gas. ISGOTT’s checklist addresses tank venting, closed-operation procedures, inert-gas arrangements and cargo tank high-level alarms. www.ocimf.org
5. Carry out an independent route check
Before requesting cargo, trace the complete line again from manifold to each initially receiving tank. Compare:
- The approved cargo plan
- The piping diagram and valve list
- CCR indications
- Reports from local operators
Resolve any mismatch. In particular, ask whether a closed valve could trap incoming cargo and whether an open valve could send it somewhere unintended.
6. Confirm readiness with shore and begin at the agreed initial rate
The ship and terminal should agree that the line-up is complete before shore starts pumping. Confirm communications, emergency-stop signals, the initial rate and pressure limits.
Begin at the agreed initial rate. The CCR monitors manifold pressure and checks that the intended tank levels rise. Deck personnel watch accessible connections and lines for leaks. Confirm with the terminal that its delivered quantity and the ship’s received quantity are consistent. Only then increase loading in the planned stages. ISGOTT’s ship–shore agreements explicitly include maximum rates, manifold pressure and pressure-surge controls. www.ocimf.org
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Why a correct line-up can become unsafe later
Valve verification continues throughout loading. As tanks fill, the crew will change receiving tanks and eventually reduce rate for topping off. Closing a tank valve too early, opening the next one too late or reducing the number of open tanks below the agreed minimum can raise pressure and increase surge risk.
A blocked-in section may also retain liquid after a valve change. The crew must follow the ship’s procedures for draining, pressure relief and avoiding liquid trapped between closed valves; they should never assume a line is empty or depressurised because transfer has stopped.
Before every tank switch, identify the next route, confirm its capacity and valve positions, communicate the change to shore when required, and monitor pressures and tank levels during the transition.
If the indications do not agree
Pause the operation and use the agreed ship–shore stop procedure if cargo appears to be entering the wrong tank, manifold pressure rises unexpectedly, a level fails to change as expected, or a leak is found. Do not continue loading while the team tries to explain an uncertain flow path.
| Indication | Immediate question |
|---|---|
| Wrong tank level rising | Which crossover or filling valve is open? |
| Intended tank level unchanged | Is its route actually open, and where is cargo going? |
| Rapid pressure rise | Is the receiving path restricted or closing? |
| Unexpected grade interface | Has cargo entered a shared line or wrong system? |
| Leak at manifold or deck line | Has transfer been stopped and containment started? |
If oil is released, follow the ship’s emergency and spill-response plan. MARPOL Annex I addresses prevention of oil pollution from operational and accidental causes; it does not supply a vessel-specific valve line-up. www.imo.org
Key lessons for cadets and junior officers
- Trace the full route. A tank valve position makes sense only in the context of the manifold, cargo main and crossovers.
- Use exact valve identification. Repeat orders and report the position actually checked.
- Treat the CCR display as one source of evidence. Reconcile it with the plan and required local checks.
- Establish a receiving path before flow starts. Confirm the minimum number of open tanks for the agreed rate.
- Verify the first cargo movement. Initial pressure, tank-level change and shore quantity should support the same conclusion.
- Recheck during tank changes. A line-up is maintained throughout loading, not completed once at the beginning.
Frequently asked questions
Do tanker cargo pumps normally run during shore loading?
Loading is commonly driven by the terminal’s pumps. The ship’s cargo pumps are operated only if the vessel’s particular loading arrangement and approved procedure require them. The line-up must therefore be based on the actual piping route, rather than an assumption that cargo passes through a running shipboard pump.
Why open receiving-tank valves one by one?
It helps the team identify and verify each valve movement. Before loading begins, however, the complete initial receiving path and the agreed minimum number of open tanks must be established.
Is an “all valves closed” rule always safe?
No. A known closed baseline may be useful for selected cargo routes, but valve status across the ship must follow the approved operational plan. Never start incoming flow toward a closed route.
What matters most when changing tanks?
Maintain a confirmed path for the incoming cargo, comply with the agreed rate and minimum number of open tanks, and monitor manifold pressure and tank levels through the change.
Final takeaway
Safe cargo loading relies on a line-up that the whole team can trace, name and verify. Start with the cargo plan, confirm every relevant valve, establish receiving and venting capacity, and begin flow only after the ship and terminal agree they are ready. Continue checking the route as tanks are switched and topped off.
For more maritime training articles, visit MaritimEducation. Further industry guidance is available from ISGOTT 6 and its ship–shore checklists.