Tell a shipowner you cut 12.4% of a voyage's fuel, and the first question is always the same: what did you give up? A slower speed? A shorter route? Something usually has to pay for it.
On a recent crossing from Guadeloupe to France, a container vessel did exactly that. Around 12 days at sea, and it gave up nothing. So here's exactly what happened, and how we know.
The table reads in one line: fuel dropped 12.4% (133.2 → 116.8 mt), while distance and duration barely moved. That's the result - but a number only counts once you know what it's measured against.
A saving only means something once you know what it's compared to.
The reference here is the route the vessel was set to sail before we routed it: its own planned voyage. Syroco's digital twin rebuilds both that reference and the route actually sailed, and compares them between the same two ports. Because both run through the same model, the comparison is like-for-like.
That also means the 12.4% is an estimate, not a meter reading - a reference voyage never physically happened, so it has to be modelled. Which is why the method matters more than the number. DNV independently reviewed and verified that method: how Syroco builds the reference and compares it to the real one. Not this specific figure - the method behind it.
The saving, split by cause. From distance: 0%.
None of it came from distance - the two routes are the same length. It came from what the ship met along the way: wind (~6.8%), sea state (~5.0%) and current (~0.6%).
Think of two swimmers crossing the same river at the same pace - one with the current, the other one against it. Same distance, right? But very different effort. A ship is not different: at a given speed, fuel is burned by resistance, not by distance.
So our routing looks for the crossing where the ocean works with the ship. Same length on the chart - less fuel in the tank.
The number will move from one voyage to the next. The method won't. That's the whole point.
One crossing is a case study. Across a fleet, over a year, it's a strategy.