The air draft of a ship is a limited resource, as if a ship is too high above the water, it won't be able to pass under bridges and other port infrastructure. It strikes me that adding 24 meters to this might not be something cargo ships are willing to do.

See, for example, https://www.joc.com/port-news/us-ports/port-new-york-and-new... , where $1.3B is being spent to raise a bridge 64 feet to accompdate larger ships. That's 19 meters, which is in the ballpark of 24.