What is the role of Nixie in underwater operations?

The role of Nixie in underwater operations primarily revolves around listening for torpedoes and protecting the ship from submarine threats. Nixie is a torpedo countermeasure system that deploys a towed array of sensors, which can detect incoming torpedoes and their acoustic signatures. By utilizing this system, a ship can enhance its situational awareness regarding potential sub-surface threats and take appropriate defensive actions if an enemy torpedo is detected.

While other options such as surveillance, countermeasures, and navigation assistance are important aspects of naval operations, Nixie's specific function is tailored toward actively monitoring for torpedo threats. This distinguishes it from other systems that might focus on different operational roles within naval warfare.