Safe alongside?

We are told, mainly by people with an axe to grind on climate change, that the world’s weather is getting more violent. And on cue, violent weather events seem to come along more regularly, whether it is this year’s hurricane season or the incidence of typhoons in 2016-17.

As this is being written 150,000 people in Ireland have no lights and the sky is a sinister orange colour over England, while an autumnal storm lashes the west coasts of the British Isles. God save the sailors on a night like this, people would pray when I was a child. They don’t seem to bother in this secular age.

But is the weather really more extreme than it was before we started to be alarmist about changing climates? Or might the consequences just seem more severe, because we deliberately neglect sea defences to “let nature take its course” as approved by the environmentalists and refuse to dredge waterways? We also build more densely, in places where the land was known to flood. A good example is the Gulf coast in the southern US states, where once a hurricane might have made a landfall over open land, which has now been built over.

But what about all these violent events in ports around the world, with container cranes being knocked over and ships blown off the berth? It happens all the time, say insurers, who aggregate the costs of these incidents, like the recent chaos in Durban, or the mayhem in North German ports, with ships being flung about like autumn leaves. Just the other day I was watching a video of a beautiful cruise ship being torn off the berth in a New Zealand port to fly across the port and crush another vessel. This is evidence enough of our changing climate, surely?

Well, maybe it is, but there are a good few caveats about these casualties that cannot surely be ignored. For a start, we ought to take into consideration the size, and the design, of modern ships. It might be in their favour when they are at sea and are less likely to be overwhelmed by extreme weather than those of earlier eras, but when they supposedly safe and snug alongside in port, it is sometimes difficult to keep them there.

They may have anticipated the weather and doubled up on the available moorings, but this might still be insufficient, if the berth is exposed (as so many are) and the effect of the wind upon the vast expanse of ship’s side just too much for the moorings to bear. A 20,000 teu containership with nothing on the deck stack is a huge ship to keep safely tethered, before you stick boxes eight or nine high on the hatches, for its full length. Just consider the windage of a big tanker or bulker lying alongside empty, a cruise ship with twelve or more decks above the waterline, or a vehicle carrier designed for 7,000 cars.

And we are still tying up ships to the quay in basically the same fashion that would have been familiar to seafarers a century ago. We may have the ropes on the drum, rather than having to wrestle them around bitts, we might have constant tension winches, but the safety of a ship alongside still depends on a cat’s cradle of wire or fibre, just like the old days. A weak link, in the shape of a frayed line and, one after another, they can all part, leaving the ship adrift and everyone screaming for tugs.

It is also worth thinking about the strength of the bollards, which may have been built when the civil engineers were anticipating smaller ships. Advanced fibre ropes have been so strong that rather than ropes breaking, it has been the bollards torn clean out of their concrete bases as the ship breaks away. There are some clever devices available that maintain a nice even strain on the moorings, but these are still few and far between. There are even a few ferry berths using magnets or pneumatic suction to hold a ship close, but it is difficult to scale up to today’s giants. But we shouldn’t necessarily blame the weather or climate change, when the ropes all break and a ship alongside less safe than we might like.

Posted 17 October 2017

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Michael Grey

Columnist and correspondent