What is "set something up" in "set sail up"? Can I understand it as an expression?
To "set sail" is an expression which traditionally means to raise the sails on a boat and start a journey. It can also be used as a way of simply saying "begin a journey" with no connection to a boat. "Up" is just being used directionally here and is not a part of "set sail" as an expression. It just tells us what direction he will be going in. Ex: Let's set sail at 5pm Ex: Where should we set sail to.