O3 gave me basically that solution. "Below is the shortest safe schedule that really works ‒ but it assumes the boat can hold the man plus two passengers (thre

O3 gave me basically that solution. "Below is the shortest safe schedule that really works ‒ but it assumes the boat can hold the man plus two passengers (three beings total). If your version of the puzzle only lets him move one passenger at a time, the puzzle has no solution: at the very first trip he would always leave at least one forbidden pair alone."