Why 19th-century sailing routes might matter again for fresh produce

Your carrier’s sustainability slide deck has a ship with sails on it, and your buyer has started asking what the emissions on your programme look like. The question underneath both, if you are the one who has to land the fruit, is narrower than both of those: does this cost me days?

No. Wind-assisted ships keep their schedules, because the engine is still there and still guarantees the ETA. The interesting part is the second-order effect, and it takes a while to arrive: wind changes the route. Where the wind is has not moved since the age of sail. Tell route-planning software that wind is worth money, and it gives you back something that looks unnervingly like a 19th-century chart.

A wind-assisted ship is not a sailing ship #

The photographs are what confuse people. A wind-assisted vessel is an ordinary motor ship with a wind device bolted to the deck. That device is one of four things: a rotor sail (a spinning cylinder that makes thrust across the wind), a rigid wing sail, a suction sail, or a towing kite. The engine does not go away; it supplies whatever power the wind does not. Wind saves fuel when it is there; diesel guarantees the arrival date. Nobody is asking a reefer importer to go back to arriving “sometime in March”.

The savings are real and modest. Published figures fall in a 5–30% band. That spread is not marketing noise: it is the difference between a purpose-built ship on a windy route and a retrofit on a poor one. The Maersk Pelican, the first tanker retrofitted with rotor sails, was independently confirmed at 8.2%.

The growth rate is the number to remember. There were 21 large merchant ships carrying wind propulsion in May 2022. There were more than 100 by 2026, and the trade association expects roughly 200 by the middle of 2027. Against a world merchant fleet of tens of thousands of ships, that is still a rounding error, too small to change the total. But it is a rounding error that has doubled roughly every two years, and is expected to double again.

The savings are geography, not equipment #

A rotor sail on a windless route saves nothing. The same rotor saves a great deal on a beam reach in the south-east trade winds — that is, with the wind coming from the side. So for the first time in about 150 years, the fuel-optimal route and the shortest route are different questions, and the difference is worth money.

Great-circle routing — the shortest path over a curved earth — won because distance was the only variable that mattered once you had an engine. Weather routing adjusted that route at the edges, to avoid heavy seas or ride a current, but the great circle stayed the basic shape. Give the router a ship that makes thrust from wind and that basic shape changes. The published work is explicit: for such a ship, the shortest path is no longer the cheapest one.

And the wind has not moved. The trade winds, the westerlies, the South Atlantic high — three wind systems the sailing fleets mapped over three centuries, because their livelihoods depended on it.

The dashed line is the standard homeward passage from the Cape under sail. It runs north on the south-east trade winds past St Helena and Ascension, then across the doldrums — the belt of calm near the equator — well to the west. From there it takes a long board — a single long leg sailed at an angle to the wind — out toward the Azores, to pick up the westerlies home. The solid line is roughly what a container service sails today. The sailing route is far longer, and it was the fast one, because it was the only one with wind in it the whole way.

Nobody is going to sail that route again. But a ship earning a tenth of its thrust from wind has a reason to bend a few hundred miles toward the wind. A ship earning a third has a stronger reason. Routes will not return to that old corridor. But they will start leaning toward it.

Which produce lanes have good wind #

Some of the trade routes that carry fruit run across the best wind geography on the planet. That is no coincidence: those are the corridors the sailing ships used, and the ports grew up on them. South Africa to Europe is the clearest case. Cape Town to Rotterdam and Cape Town to the UK run straight up the old Cape route, crossing every wind belt in the Atlantic in turn.

Peru and Chile are the instructive contrast, because “South America to Europe” sounds like a single voyage, and it is not. Both lanes transit the Panama Canal. Their Atlantic leg therefore begins in the Caribbean, and stays in the northern half of the ocean the whole way. That means north-east trade winds, then the Azores high, then the westerlies. They never meet the south-east trade winds at all. The routing that does meet them is the south-about one: around Cape Horn or through the Strait of Magellan, south of the continent instead of through the canal. Today that is the contingency for when canal capacity is short. It is also, almost exactly, the corridor the sailing fleets used.

That is the discipline this whole subject needs. Good wind is not a fact about a country; it is a fact about a route, and two lanes out of the same port can have different answers.

Morocco often comes up in this conversation, but it does not really belong. Most Moroccan produce reaches Europe by truck and ferry rather than in a deep-sea container, so the wind question barely touches it.

Then there is the problem with all of this.

Your fruit is on the worst ship for it #

Count the fleet by what the ships carry, and the problem becomes obvious. As of June 2026 it was 37 tankers, 24 bulk carriers, 24 ro-ro and ro-pax vessels (vehicle carriers, and vehicle-and-passenger ferries), and 19 general cargo ships. That is the whole hundred. Container ships are essentially absent from that list — and container ships are where your reefers are.

There are two reasons, and neither is about to disappear. Deck space: a rotor needs open deck space and undisturbed airflow, and a container ship’s deck is where the boxes go and where the cranes reach. And speed: a fast ship makes its own headwind. The faster it goes, the further forward the apparent wind swings, and the less any wind device can do with it. (Apparent wind is the wind the ship actually feels, once its own speed is added in.) Container services run faster than bulkers, so they get less from the same equipment.

There is engineering work on both — rotors that tilt or retract, mountings that lift them above the stacks — but be honest about where things stand today. This arrives on the ships carrying ore and crude oil first. It reaches the reefer lanes later.

Does the wind power the cold chain? #

This is the question worth asking about perishables specifically, because a reefer’s cooling is an electrical load rather than a propulsion one and it runs the whole voyage. A reefer-heavy service draws something like 5–10 MW for it, and up to 15–20 MW on the largest ships at maximum reefer count. A ship under sail could in principle regenerate power, by spinning a shaft generator from a propeller the wind is turning. If that worked, the cold chain’s power bill is the obvious place to aim it.

We could not find published pilot data showing that done for reefer loads, and today the numbers work against it. A rotor sail is driven by an electric motor, around 90 kW per rotor, from the same plant the reefers draw on. It is a debit, not a credit. It is also trivially small: a handful of rotors against a plant measured in megawatts is noise, and the propulsive return is several times the electrical input. But that return arrives as fuel saved by the main engine, not as free power for your boxes.

Regeneration under sail is real in principle, and shaft generators can already work in both directions, taking power as well as giving it. Treat “wind runs the reefers” as unproven until somebody publishes numbers from a ship doing it.

What actually reaches your invoice #

Not a shorter transit. The saving shows up on the emissions line.

Shipping sits inside the EU Emissions Trading System, and carriers pass the cost of allowances through as a surcharge on European trade lanes, so less fuel means fewer allowances. Separately, FuelEU Maritime prices the greenhouse-gas intensity of the energy a ship uses. Wind is the only technology in that regulation with a reward factor of its own. A vessel drawing 15% or more of its propulsive power from wind gets up to a 5% reduction on its calculated intensity. That is on top of the fuel it did not burn.

So the honest version is a slightly smaller surcharge and a slightly better reported footprint, on the same transit time. That is a small number today. It is also the only framing a perishables buyer should accept. A pitch that offers wind savings in exchange for schedule flexibility is asking you to pay in the one currency your cargo cannot spare.

What changes on your tracking page first #

Long before this changes your costs, it changes something you look at every week.

A tracking page draws the route the bill of lading describes — origin, transshipment, destination, joined up. A wind-routed vessel is not on that line. It is west of it, sometimes by hundreds of miles, because a router decided the wind out there was worth the distance. All of this looks exactly like a problem: the marker sits off-route, the drawn line and the AIS track disagree, and nothing on the page says why. We have written about why tracking positions are wrong for the ordinary reasons; this adds one that is not a fault at all.

The practical consequence is about what you do with the alarm. A vessel that is off the drawn route because of weather routing is fine and needs nothing from you. A vessel that is off it because it missed a connection is a problem, but one you usually have days to fix. Those two look identical on a map and completely different on a schedule. The way to tell them apart is to watch the ETA rather than the position. That is the job Trackberry does on the containers you already have on the water.

FAQ #

Do wind-assisted ships take longer than conventional ships? #

No. A wind-assisted vessel is a motor ship with a wind device added, and the engine makes up whatever the wind does not supply, so it holds the same schedule. Voyage optimisation for these ships is run against a fixed arrival time — the saving is taken as fuel burned rather than as time. Any proposal that asks a perishables shipper to accept schedule flexibility in exchange for wind savings is a different offer altogether, and a much worse one.

Are there wind-assisted container ships? #

Essentially none. Of the hundred-odd large vessels carrying wind propulsion in mid-2026, 37 were tankers, 24 bulk carriers, 24 ro-ro or ro-pax (vehicle carriers, and vehicle-and-passenger ferries), and 19 general cargo ships. Container ships are absent for two reasons. Their deck is occupied by cargo and served by cranes. And they run fast enough that the apparent wind swings forward, which gives a wind device less to work with. (Apparent wind is the wind the ship actually feels, once its own speed is added in.) Retractable and elevated mountings are being developed for exactly this reason, but reefer cargo will see this later than the bulk lanes do.

Does wind-assisted propulsion power the reefer containers? #

Not on any published evidence. Cooling is an electrical load supplied by the ship’s generators, and a rotor sail actually consumes electricity — roughly 90 kW per rotor — from that same plant. The consumption is small against a reefer plant drawing 5–10 MW on a reefer-heavy service, and the propulsive return is worth several times the input. But the benefit arrives as less fuel burned by the main engine, rather than as free power for your boxes.

How much fuel do wind-assisted ships actually save? #

Published figures fall in a 5–30% band, and where a given ship falls within it depends far more on its route than on its equipment. The Maersk Pelican rotor-sail retrofit was independently verified at 8.2%. Purpose-built vessels achieve more. A retrofit on a route with poor wind achieves very little, which is why these systems are specified against a trade route rather than against a ship.

Will wind-assisted shipping reduce what I pay for freight? #

Marginally, and through the emissions line rather than the base rate. Less fuel burned means fewer EU ETS allowances surrendered on European trade lanes. FuelEU Maritime also gives wind propulsion a reward factor worth up to 5% off a vessel’s calculated greenhouse-gas intensity. Expect that to show up as a slightly smaller surcharge and a better reported footprint, not as a cheaper box or a faster transit.