Review planned versus actual voyage fuel
A practical post-voyage review that separates route, time, consumption and price differences before changing the next estimate.
Keep the original plan
Save the assumptions used before departure. Overwriting them with the actual result makes the estimate look better without explaining the difference. Keep the route distance, expected hours, burn rate, fuel quantity and price timestamp together.
Separate quantity from price
A higher final bill can come from more fuel, a higher unit price or additional delivery charges. Review those differences separately. Compare the same units and make clear whether the figure is fuel consumed, fuel purchased or a tank-level estimate. Purchases and consumption are not interchangeable.
Use a short variance table
Record planned and actual distance, underway hours and fuel quantity in adjacent columns. For a teaching example, 500 litres planned and 550 litres actually used is a 50-litre difference, or 10% of the plan. It says nothing by itself about the cause. Check whether the route or waiting time changed before concluding the vessel burned more at the same operating point.
Write an explanation that can be checked
Note detours, time at anchor, generator loads and observed conditions, with the log entry or invoice supporting each explanation. If the source is uncertain, label it uncertain. A plausible story is not a measured cause.
Change one assumption at a time
Update a vessel burn-rate assumption only when comparable observations support it. Preserve unusual voyages as useful exceptions rather than silently making them the new baseline. Use SeaWise for the next estimate with the revised, documented inputs and keep a separate operational record wherever your vessel requires one.