Cruising: Sailing in Nero's wake

The SeaDream in the Corinth Canal. Photo / Supplied

Ewan McDonald writes a letter from the Corinthians' canal, an emperor's project two millennia in the making.

Here's how it goes with ships and the sea, in my admittedly limited experience. Boat, passengers, crew, pretty much alone in the universe. Vast expanse of deep blue below (the watery bit); lighter blue everywhere else (the sky). I'm not the first to notice this: poets have waxed nautical about the limitless and empty ocean since Homer started scribbling on his wax tablet.

I am standing on the - forgive the ignorance of maritime terms - front bit of SeaDream I (which is, technically and legally, a yacht and not a ship). Sheer cliffs, eight or nine storeys high, are just a metre on either side of the technical and legal vessel thing, and not too much water is underneath its keel as we inch through a passage that is not vast, limitless or empty.

Sipping champagne and chatting with fellow travellers, it feels this is somewhere a ship - or a yacht - shouldn't be. Hemmed in by land. No place to go but straight ahead. Not under its own power: a tug is pulling it. Not under its master and commander: he has had to give the bridge to a local pilot.

SeaDream is navigating one of human engineering's more whimsical endeavours, one that owes its existence to four megalomaniacs who were determined to best nature and the gods: the Corinth Canal.

About an hour ago we rock'n'rolled up to the canal entrance, which looks like an everyday European harbour, sea walls on either side. A pilot boat heaved to, or hoved to, or did some kind of maritime manoeuvre, off to the right. I mean starboard. Ropes were thrown. Then they were thrown again and this time caught by the crew.

The pilot came aboard. We knew he was the pilot because he wore blue overalls and a captain's hat from the 2-euro shop that said PILOT in gold braid.

Entering the canal has been described as "being swallowed by the earth". On either side are 90m high sandy cliffs. There is 8m of water below us; pretty much what SeaDream needs to stay afloat. It is just over 18m wide; at its widest the canal is 24m wide, mostly its 20m.

Bridges are above us: a railway line, a provincial road, a motorway. Sometimes people bungy off them. It's school holidays in Greece; children point and giggle. Cars cross the motorway bridge high above. Fishermen harrumph as the wake scares the fish.

The cliffs are striped, dark here, ochre there: that strata might mark Caligula's time, or Caesar's; perhaps that dark line was when Alexander the Great passed by.

Greece. Centre of the known universe, civilisation, philosophy in about 1000BC. Hard to voyage around the islands and mainland. Three-headed dog-god things and women whose hair was made out of snakes guarded the really cool resorts from unwanted tourists.

There's one place where two seas almost meet: the Aegean and the Adriatic. The waves of one sea crash on to its shore at Corinth; the waves of the other lap on the sun-loungers and ice-cream stalls on the other side of the peninsula. As the seagull flies, they're only 6km apart. The way the land lies, you have to sail 343km around the pointy bit to get from here to there.

Smart people, the Greeks. They did all that mathematical stuff where you work out that a+b = a way shorter route around the peninsula if you cut a canal through the middle.

Unfortunately there's always one grumpy old bugger in the way of progress and in this case it may have been Poseidon, god of the seas, who was a really angry god and thought it was a bad idea to interfere with nature. Legend (and they're really big on legends in this part of the world) has it that he cursed anyone who dared interfere with the way of the universe.

The slightly nasty tyrant Periander of Corinth got the message and abandoned his attempt to build a canal in 700-ish BC. He chose to build a stone carriageway so ships could be towed across land. Two and a bit millennia later, the remains are still visible.

Three of the darker souls who've drawn breath on this planet riffed on the idea: Julius Caesar, Nero and Caligula. Nero turned the first sod with a golden hoe in AD67 - 6000 slaves died within weeks. Assassinations, landslips, bankruptcies, plagues of frogs, games of thrones: over the next couple of thousand years, they all got in the way of the project.

Then in the mid-19th century a British consortium thought: We can make a quid here. Construction got under way in 1881 but was hampered by geological and financial problems that bankrupted the company. It was completed in 1893 but experienced constant financial and operational difficulties.

The narrow canal makes navigation difficult; the high walls channel high winds down its length, and different tides in the two gulfs cause strong currents. For these reasons, many ship operators did not bother to use the canal and traffic was far below what had been predicted. World War I wasn't good for business either.

The walls have been unstable from the start, causing slips; ships' wakes undermined them, leading to more landslides. It became a battlefield in World War II because of its strategic importance, causing serious damage. Later, retreating German forces used explosives to set off landslips to block the canal, destroyed the bridges and dumped locomotives and bridge wreckage into the water. US army engineers cleared it in 1948. Now it's used mainly for tourist vessels.

As surprisingly as the walls closed in, a panorama opens out. SeaDream is back where it should be; in another ocean, its waters darker, deeper. The Aegean. Homer called it the wine-dark sea. I ask for another champagne.

The writer travelled courtesy of Emirates and SeaDream Yacht Club.