With reference your article on the Dubai Dry Docks (NCE 11 April), the gates were designed by T F Burnes & Partners from a concept by the main contractors.
A vessel/barge hitting the props while the dock is flooded and the gate up need not be inevitable, for it's a matter of vessel draft and controlled hauling out.
I note two prop upper diaphragms are missing on the west side of the gate.
L A Harris, leslie. harris@lineone. net