Shaq's Boat Name

Listen up, you clearly don't get it, so let me break it down for you. Shaq is a famous basketball player, and "freethrow" is also related to basketball. Get it now? This joke uses the term in a humorous way, get it? The joke implies that Shaq is so bad at free throws, that he can’t even sink a boat, using the same word. It's a funny comparison, okay?