If the people on the boat are close to the shore, it can't be an odd number of people on the shore (otherwise there will be more girls on one side and more boys on the other). If the people on the shore are always even, then there can only be 0 or 2 people on board. If the ship is going to move back and forth, there can only be two people. If the people on the shore are equal, there can be no inequality between boys and girls. Otherwise, there will be more girls here and more boys there when the ship comes ashore. In short, there can only be one man and one woman on board, and no more people can be added or subtracted, nor can men be changed for women or women. No one can pass except the boatman.

If someone can stay on the ship when it comes to shore, it is not landing. The question becomes something that primary school students can answer without pictures.

If a man can't sail, send a man and a woman to the opposite side at a time, and the last woman will get off the opposite side with the sailing man.