You also can't argue that they have to dump it overboard because of the costs that the delays will cause, because such costs are explicitly excluded in the 2004 rules on general averages [1]
[1] Rule C, paragraph 3 https://shippingandfreightresource.com/wp-content/uploads/20...
The iminent danger i refered to is rule A:
>RULE A1.There is a general average act when, and only when, any extraordinary sacrifice or expenditure is intentionally and reasonably made or incurred for the common safety for the purpose of preserving from peril the property involved in a common maritime adventure.
While imminent danger is not used, the rule itself can only be applied when the jettisoning of cargo is essential to the common safety. This most often happens when the vessel is in imminent danger of sinking and needs to shed weight.
If the only way to get the ship unstuck from there were to jettison stuff out, and there were no way to otherwise free the ship (or safely unload the cargo) then maybe you'd be able to argue in favor of a general average, but given the circumstances that is not the case.
The ship isn't exactly stuck in antartica, so safely unloading, although expensive, is an option that would preclude jettisoning (and therefore the general average)
Depending on what's in the containers, I'd expect most would probably float, at least for a little while until water leaks in. Maybe long enough to drag them out of the way; either to the sides of the channel or out of the water altogether.
Light boats are less stable. One of the few that could make this situation worse would be the damn thing capsizing.
I wonder what the options even are for removing the containers? I assume they're very securely strapped on most of the time, and maybe there's not any reasonable way to get any of the containers loose outside of a port without making the whole pile unstable.
It seems to me that if they can't move it by any normal means, they could just start pushing cargo containers overboard and fish them out until it's light enough to move.
I could also a lot of plausible reasons why they wouldn't do that:
- it wouldn't work (no equipment to move containers)
- the ship's owner doesn't want to do that and no one has the authority to force them
- the ship's owner wants to do that, but the owner of the cargo doesn't want them to
- the cost of lost cargo is more than the cost of delaying other ships
- it would take too long or be too messy to clean up