Conventional wisdom would suggest that only the largest container terminals can achieve productivity rates of more than 30 moves per crane hour, while even they require major box exchanges per ship call in order to do so. Even fairly busy import/export facilities often struggle to post anything better than 25 moves per crane hour. At the bottom end of the scale, feeder ports have traditionally struggled to maintain high productivity levels, pleading calls from small vessels generating modest box exchanges as the main mitigating factor.
The government has predicted that demand for aggregates in the South East will increase from 38m tonnes in 2003 to 45m tonnes in 2010. Twenty-one per cent of the sand and gravel used in England and Wales is supplied by the marine aggregates industry – but in the South East, 33% comes from the seabed.