I agree. For example, it would also allow ships to make up time lost to rough weather by ignoring the speed limits later in the passage (which is probably not g

I agree. For example, it would also allow ships to make up time lost to rough weather by ignoring the speed limits later in the passage (which is probably not good for the environment). I also don't know that a blanket speed limit makes sense for all ships. The longer the waterline length of a ship (for a given weight) the easier it is for it to make a given speed. I feel like a better metric could be used, like fining vessels for trips which consume more than X tonnes of fuel for a ton of cargo where X is designed to be met only by building highly efficient ships or by existing ships operating at reduced speed.