Senior project manager Peter Mallin explains the wet side challenges faced by ports in welcoming the latest generation of megaships.
The oceans’ biggest beasts are multiplying in number, with effects stretching from open sea to hinterland connections. Wider, taller and larger ships are more susceptible to currents and wind loads, and are by nature more difficult to navigate to port within existing spatial and towage constraints. Bigger or more tugs will be needed, and tug operators need to be specially trained for the task.
Megaships need wider, deeper approach channels and harbour basins. When fully laden, megaships can draw -16m. Many European ports provide -17m low tide draft, while Euromax in Rotterdam has been dredged to -19.5m. Maintaining an approach channel to that depth is a potentially crippling cost and some ports, for now, have settled for deepening berthing pockets only. Ships are able to manoeuvre in and out only at high tide – a solution put into practice at Hamburg Port. Real-time simulation can help to ascertain optimum navigation strategies and optimise harbour upgrade requirements and towage provisions if necessary.
Offering efficient connections
New Panamax megaships apply proportionately larger forces against the quay than their forbears, with greater wind surface, displacements and prop wash. Deepening of berth pockets can critically reduce the cantilever strength of quay walls. Allied with greater lateral loading on mooring bollards and fenders, and increased loading from the larger reach cranes serving megaships, wall reinforcement may be required. Ground engineering solutions such as tie-back anchors can provide a cost-effective way to extend the life of existing walls, avoiding the need for longer, stiffer new piles. In many situations, additional riprap protection is needed to protect against scour.
As with all engineering decisions, careful study of structural capacity and wind records is essential to determine if upgrades are really necessary.