How mine-catching cables would protect a ship's hull

What exactly are mine-catching cables?

Cables or heavy rope suspended on poles and framing outside the hull, intended to set off mines before they reach the ship.

Steel cables or heavy rope would hang from poles and framing outside the hull. The intention is to make an explosive device detonate before it reaches the ship itself. As with a cage around a modern armoured vehicle, the explosive would go off before making contact with the protected surface.