It wouldn't be "completely unpredictable".... pulling some numbers from a hat, let's say powered-ship takes 6 days, wind-ship takes 8-11 days. Depending on the

It wouldn't be "completely unpredictable".... pulling some numbers from a hat, let's say powered-ship takes 6 days, wind-ship takes 8-11 days. Depending on the severity of being late you would plan for perhaps 10 days. Or 12 days if missing your port slot is severe. You would be able to track the wind ship, so your window of arrival will narrow as the journey progresses. There must be a portion of the industry that will navigate this complexity in exchange for the fuel-free benefits.