What dinghy? What Freighter? Shouldn't you be using 'a' instead of 'the'?
I guess it would depend on what is powering the dinghy. If it's relying on people using oars, it would be difficult but not impossible. If it's a motor or sails, it would be a rather simple task.
The question is referring to something on "Lost". Anyway, the answer would be that the freighter was moving closer to the Island. That's why it could reach it. Either that, or you just have to count that as an error.