Shipping oil half way round the world – from the US Gulf coast to East Asia – is a major logistical challenge. Such extra-long-haul shipments have to use the largest tankers – VLCCs of 2mn barrels – to make the economics work.

But many US Gulf ports are not designed for this. They cannot load VLCCs, requiring offshore transhipment from smaller vessels, which of course adds to the cost. (CONTINUED - 323 WORDS)