Bigger ships, bigger risks at sea

Diagram: Arabian Supply Chain

Diagram: Arabian Supply Chain

Do bigger ships necessarily mean bigger risks at sea?

Time was when the Panama Canal was one of the inhibiting factors in the size of container ships. A “panamax” ship is, literally, the maximum size of a ship that would fit in the Panama Canal.

Typically a panamax container ship (1985-) had a maximum capacity of around 4500 TEU (twenty foot equivalent unit) containers. That’s 6 stacked below, 8 on deck – 13 abreast.

With the Panama Canal expansion came the new “panamax” (2014-) 12,500 TEU. That’s 6 stacked below, 10 on deck – 20 abreast.

Meanwhile the engineers and economists came together and worked out that the most efficient way to save fuel is to slow the ships down. Drag increases geometrically with speed in the water so – twice the speed = fours time the drag = much more power/fuel required. Wartsila (marine engine manufacturer) has calculated that reducing the speed of container ships, from the old norm of 27knots, to 18knots can save almost 60% in fuel consumption. Maersk reckon that one of their modern “super-slow-steamers” travelling from Europe to Singapore can save 4000 tons in fuel – that’s around $2.5m! Of course that’s great for the environment and saves money so everyone’s a winner…

However, “super-slow-steamering” can add up to a week to a trans-pacific crossing, so capacity had to increase to just match the same demand. Enter the latest container ships in service: The 18,000 TEU (8 below, 10 on deck and 23 abreast) behemoths that are the Maersk “Triple Es”, CSCL Globe etc. – by 2018 22,000 TEU ships are planned, with 24,000 TEUs rumoured for the future beyond.

These enormous ships are a wonder to behold, however they come with a potential for massive disaster.

With the MV Rena running aground and breaking her back off New Zealand, 900TEU were lost overboard (25%); MOL Comfort  went down (eventually) with 7,041TEU & the MSC Napoli had 2300TEU aboard.

Accidents do happen and of course with the world’s weather becoming more extreme, violent and unpredictable, these latest ships are far less able to avoid bad weather systems and far less manoeuvrable when inevitably experiencing them.

The environment has certainly benefitted from super-slow-steaming – but these bigger ships have certainly raised the stakes when it comes to risk in the future.

Further reading

Wall Street JournalThe Guardianseatrade maritime news





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