Why can’t a naval ship have chains extended on sides to keep torpedos from reach it?

Question

I’ve always thought a navy ship could have arms extending from each side, out say 20′ or so that holds some sort of draping system, like a chain or something, that extends below the bottom of the hull. Then, if a sub fired a torpedo at it, it would either explose on the chain or just get caught up in it.

In: 3375

Answer 1

That’s kind of what DARPA is trying to do for vehicles with its iron curtain experiment. It’s an extendable plate that lowers and cuts projectiles in half before they hit the armor.