Is it permissible to believe that a protective barrier protects you?

So as we know believing that the nazar 🧿 eye ,,protects" you is shirk. But my question is when you are for example in a boat and you see a shark drawing near you, so you use a protective barrier (crates for example) so the shark is less likely to kill you. Now, does believing the crates will protect you from the shark shirk?