Twenty-one metres wide, walls ninety metres high. A minehunter in the Corinth Canal

The Spanish minehunter Turia, serving in NATO's Standing Mine Countermeasures Group 2, has transited the Corinth Canal, the Spanish defence staff reports. The group operates in the Mediterranean and, in the Spanish wording, upholds freedom of navigation in areas of strategic interest. The photograph from the transit says more than the statement: a grey hull between two vertical walls of limestone, with a few metres of water on either side. Few warships in Europe can take this route, and it is worth knowing why.

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02 october 2026   |   23:54   |   Source: Gazeta Morska   |   Prepared by: Kamil Kusier   |   Print

fot. Sztab Generalny Obrony Hiszpanii

A trench that saves hundreds of miles

The Corinth Canal cuts through the Isthmus of Corinth, the narrow strip of land joining the Peloponnese to the rest of Greece. It is 6.3 kilometres long, which makes it one of the shortest ship canals in the world, and it is a trench dug through solid rock, without locks, at sea level. It is around 25 metres wide at the waterline and around 21 at the bottom, eight metres deep, and its walls rise in places to 90 metres. A ship passing through looks up as if from the floor of a gorge.

Thanks to the canal, a vessel sailing from the Ionian Sea to the Aegean, from Italy to Piraeus or to the Cyclades, for instance, does not have to round the Peloponnese. The saving is several hundred miles and one to two days at sea, depending on speed. In the age of sail that was an enormous shortcut; for today's container ship it is irrelevant, because a container ship cannot get through.

What fits and what does not

The canal is too narrow and too shallow for almost all modern merchant shipping. Vessels of up to roughly 18 metres in beam and about seven metres of draught can pass, in one-way convoys, with a pilot and often a tug at the bow, because in the narrow cut wind and current can push a hull onto the rock. The transit takes about an hour.

In practice three groups use it. The largest is yachts and small cruise ships, for which the canal is both a shortcut and an attraction; thousands of yachts a year pass from the Gulf of Corinth to the Saronic Gulf, Polish ones among them, because the route from the Adriatic and the Ionian to the Cyclades is one of the classic charter itineraries. The second is small cargo ships and ferries serving ports on both Greek coasts. The third is small warships: patrol vessels, cutters and, precisely, minehunters, which are a dozen or so metres wide and draw a few metres. For a NATO mine countermeasures group moving from the western Mediterranean to the Aegean the canal is the natural route, and the passage doubles as a ship-handling exercise.

The record belongs to the cruise ship Braemar, which transited in 2019 with a beam of over 22 metres, leaving about a metre of water on each side. Larger ships have had to turn back.

From Nero to a Hungarian engineer

The idea is two and a half thousand years older than the canal itself. As early as the sixth century BC the Corinthian tyrant Periander considered a cut, but built instead the diolkos, a paved trackway across the isthmus along which ships were hauled on trolleys from one gulf to the other; its remains are still visible beside the western entrance. Julius Caesar and Caligula returned to the plan, and in AD 67 Nero ordered digging to begin, symbolically turning the first sod himself; his death stopped the work. For the next eighteen centuries the isthmus stayed dry land.

The modern canal was built between 1881 and 1893, after Greece gained independence and the success of the Suez Canal proved such projects feasible. It was designed by the Hungarian engineers István Türr and Béla Gerster; the original French company went bankrupt and a Greek one finished the job. The digging went through limestone and soft marl, which was a problem from the start, because the walls have been sliding ever since.

A canal that closes every few years

Landslides are the chief worry of the operator, the state company AEDIK. After a series of collapses in 2021 the canal was closed for a year and a half, until mid-2022, and the stabilisation of the walls went on long afterwards; shorter closures had happened before. Every closure means yachts and small ships must round the Peloponnese, and the region loses the transit fees, which are charged by vessel length and run to a few hundred euros for a yacht and a few thousand for a ship.

Road and rail bridges cross the canal, and at both entrances submersible bridges sink below the water to let ships through, one of the sights of Isthmia. Tourists bungee-jump from the bridge in the middle and watch transits from above, where a whole ship can be seen at once. That is why the Spanish photograph from Turia's deck, taken at water level, is so unusual: it shows the canal from the side the tourist never sees.

Why it matters from Gdynia

Polish warships have rarely been in this canal, because the Polish Navy operates in the Baltic and ventures into the Mediterranean mainly within NATO groups. Poland's Kormoran-class minehunters, about 10 metres wide and drawing less than three, would fit with plenty of room, and if they were ever assigned to the southern mine countermeasures group rather than the northern one in which they serve today, the Corinth Canal would lie on their route. The Spanish Turia, built under British licence with a glass-reinforced plastic hull, is a ship of the same class as the Polish units that preceded Kormoran, so the photograph from the canal shows what ORP Flaming or ORP Czajka would look like in the same place.

The Corinth Canal matters nothing to world trade today and never did. It matters to those who fit through it: sailors, small shipowners and navies that know how to use a shortcut. For a hundred and thirty years it has stood as proof that the shortest way is not always the widest.

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Kanał Koryncki niszczyciel min Turia SNMCMG2 NATO Grecja Peloponez żegluga

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