Yes, "to man" means there are (old) people operating (manning) the boat. "Fruit flies like an apple." Yes... yes, they do. Compare it to "time flies like an arrow" and we recognise "fruit fly" as an insect. A "time fly" does not exist. "I saw Mount Tai flying to Beijing." This is called a 'dangling participle', because it isn't clear whether "flying to Beijing" means you or the mountain. Comedy begins. There are some hilarious examples of dangling participles in Alanis Morrisette's "You Oughta Know" and Robbie Williams' "Feel". See if you can find them. :)