Why was the trip of Magellan difficult?

He and his men went right around the world in tiny, ungainly boats. If you have ever been on the sea at all you can imagine the immensity of it. They had no maps or charts. Many of them thought the world was flat and had no idea of the raging seas south of Cape Horn or the tip of Africa. They had little food and certainly no fresh foods.

Magellan went the other way and since he did not have enough knowledge of the direction he was going, he had a difficult time. Also he died in his exploration