I don’t like to put words in the lock operators mouth…but….
They would perfer that we use marine radios to call them if possible.
They know when a barge is coming through when the barge radios to them, so that could be as little as 30 minutes.
There is a website that will tell us when a barge has gone through the up or down stream lock and a person can guess about the time it will be arriving at 3…but they may stop for some reason or their destination may be prior to arriving at 3. So it’s still a crap shoot on arrival time.