You can't possibly have 10 helis safely unloading cargo at once from a single ship, that'd be an invitation for disaster. Also, doing that in the dark would simply not work. 10 sorties/hour is also unrealistic; with proper cranes and infrastructure at port it would take something like 10 minutes, with choppers it would take more time.

IMHO if helis would even work (which is debatable and debated here), the optimistic estimate is that you could unload something like 20 containers per hour, 300 containers per day, so 30 days for the cargo. It seems plausible that you can dredge the banks and drag the ship out much quicker than that.

>You can't possibly have 10 helis safely unloading cargo at once from a single ship

5 loading at a time, while the other 5 unloading on the ground - plenty of space as ship is 1300 feet long.

> doing that in the dark would simply not work

you flood the ship and the space around with light. Almost 30 years ago we did a night ship unload at an unprepared location - no issues.

>10 sorties/hour is also unrealistic

doing it with crane we did about 15+ - we weren't union operation though - we were paid for performance, not time :) and being young we were moving fast. With chopper not much different if weather is ok.

> 10 helis, 20tons each, 10 sorties/hour = 200k ton in 5 days.

Among the many problems with this calculation is that shipping containers can't be freely subdivided and recombined, and can have a loaded weight over 30 tons.

EDIT: And to address the crossing edit:

> 10 helis, 1 container/sortie, 10 sorties/hour = 10000 containers in 5 days.

...and the heaviest-lift helicopters can't lift 30 tons.

One would expect lightest containers on top, heaviest at the bottom. CH53 can lift 15ton, so probably it can unload several top layers.

Just set up a ski lift-like structure on both sides of a canal, and run it with containers instead of skiers