Never Wait at Anchorage Again: How Much Fuel Could Just-in-Time Arrival Actually Save?
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How Much Fuel Is Hidden in Anchorage Waiting?
A new Japan-linked project will combine VDES, live AIS and port information to keep updating when a ship should arrive. The prize is simple: stop burning fuel to reach a berth that is not ready.
A ship can be perfectly on schedule and still arrive ten hours too early. If the berth is occupied, the result is one of shipping's least efficient operating patterns: maintain voyage speed, reach port, drop anchor and wait.
PASUVO is being developed to move that waiting time backward into the voyage. VDES will support ship-to-port information exchange, live and historical AIS data will help estimate vessel movement, and port conditions will continuously alter the target arrival time.
The fuel saving does not come from VDES itself. It comes from learning about the delay early enough that the ship can turn hours of expected anchorage into hours of slower steaming.
The fuel problem is not anchoring. It starts hundreds of miles earlier.
Hurry up
The ship protects the published ETA because the berth situation is uncertain or the revised information arrives too late to change the voyage economically.
Wait
Main propulsion savings begin only after the high-speed portion of the voyage has already been completed.
Receive the delay early
A trusted berth-readiness update gives the vessel permission to use part of the expected waiting time before reaching port.
Slow down
The ship arrives closer to the time the berth, fairway and required nautical services are actually available.
PASUVO is trying to turn port readiness into a live speed instruction
The project joins Sternula, Sternula Japan and Tokyo University of Marine Science and Technology. Its architecture combines ship-port communications with historical and live vessel data and data-driven optimization.
The arrival-information loop
Port state → vessel actionPort changes
Berth, service or vessel conditions alter the realistic arrival window.
AIS updates
Historical and live vessel movement helps describe the evolving traffic situation.
Target recalculated
Route, speed and arrival timing are optimized around the new conditions.
VDES sends
The updated arrival information can move between ship and port digitally.
Ship adjusts
The vessel changes speed while sufficient distance remains to create savings.
Repeat
The target continues to move as port and voyage conditions change.
How early the ship learns about the delay changes the value dramatically
Optimize the whole voyage
IMO's global containership analysis found the largest average saving when JIT speed optimization could begin across the full voyage.
Final 24 hours
Even one day of useful advance information captured a meaningful portion of the available efficiency.
Final 12 hours
The study still found material average savings when the speed change began only half a day before arrival.
A few knots matter because propulsion power does not fall linearly with speed
Slow steaming attacks the high-energy part of the voyage
For displacement ships in a suitable operating range, required propulsion power often changes roughly with the cube of speed. Real vessels depart from that simplified relationship because of weather, hull condition, propeller performance, engine limits and auxiliary loads, but the curve explains why early speed reduction can be much more valuable than simply eliminating fuel consumed at anchor.
The berth forecast does not need to be perfect. It does need to be trusted.
A vessel cannot safely convert every predicted hour of delay into slower steaming if the berth could suddenly become available again. The useful variable is therefore not simply “expected waiting time.” It is the amount of waiting time the operator is confident enough to use.
High-confidence delay
Most of the expected waiting window can potentially be converted into additional sailing time while retaining a small recovery buffer.
Uncertain berth
Slow down, but preserve enough speed margin to recover if the preceding vessel leaves earlier than expected.
Weak forecast
A large theoretical delay may produce little practical JIT opportunity if the master cannot rely on it.
Three different savings are hiding inside one JIT voyage
| Mechanism | What changes | Fuel effect | What limits it | JIT value |
|---|---|---|---|---|
| Lower voyage speed | Waiting time is converted into additional sailing time. | Main-engine power demand falls. | Minimum economical speed, schedule and weather. | Largest lever |
| Less anchorage | Ship reaches port closer to berth availability. | Auxiliary and hotel-load fuel at anchor is reduced. | Some final waiting may remain unavoidable. | Direct saving |
| Less arrival maneuvering | Less low-speed circulation or repositioning while waiting. | Can reduce inefficient maneuvering consumption. | Port layout and traffic conditions. | Secondary |
| Better berth utilization | Arrivals align more closely with actual terminal capacity. | Fleet-level efficiency rather than one simple fuel line. | Requires port-side participation and reliable timestamps. | System benefit |
| Over-slowing | Ship reduces speed below an efficient or recoverable range. | Theoretical savings may not materialize as modeled. | Engine load, fouling, weather and berth uncertainty. | Control needed |
VDES is the nervous system, not the fuel-saving device
Beyond AIS position reports
VDES expands the maritime VHF data environment with higher-capacity digital channels suitable for structured ship-to-shore and shore-to-ship information exchange.
Port can talk back
The JIT problem requires more than knowing where the vessel is. Port readiness and revised targets must also reach the ship in a machine-readable operational workflow.
Moving into SOLAS
IMO adopted the VDES regulatory framework in 2026, with the relevant new provisions expected to enter into force in January 2028.
“Never wait at anchor” is the goal, not a realistic guarantee
Berths move
Cargo operations can finish earlier or later than forecast. A JIT plan needs recovery margin when the berth-ready target changes.
Weather moves
Wind, waves, current and route restrictions can alter the speed required to protect the new arrival target.
Ships have speed floors
The mathematically ideal JIT speed may be below the practical operating range of the main engine or incompatible with other voyage constraints.
Ports need more than a berth
Pilotage, tugs, fairway access, linesmen and terminal services also have to align with the arrival window.
Contracts still matter
Charter-party obligations and commercial incentives can determine whether the party controlling speed actually benefits from slowing down.
Late information has less value
A six-hour delay discovered 1,500 miles out is a speed opportunity. The same delay discovered twenty miles from the pilot station is mostly still waiting time.
Just-in-Time Fuel Savings Simulator
Give the ship a distance to go, current planned speed and expected berth delay. Then change how trustworthy the port forecast is. The model calculates how much of the waiting can be absorbed at sea and how much fuel might be avoided.
How much is an early berth-delay message worth?
The model compares “rush and wait” against a JIT case using a simplified propulsion-power curve, a minimum operating speed and a confidence-adjusted arrival target.
Most of the expected anchorage delay can be converted into slower steaming while retaining a recovery margin.
Enough distance remains to absorb a large share of the expected delay without reaching the model's minimum speed.