The US and Chilean Navies have successfully completed a four-day passing exercise (PASSEX), aimed at promoting communications, interoperability and partnership between the two navies, as part of Southern Seas 2011.

Two US Navy guided-missile frigates, USS Boone (FFG 28) and USS Thach (FFG 43), participated in a series of exercises with Chilean Navy submarine Carrera (SS-22).

The PASSEX exercises included unit-level training in submarine familiarisation, passive and active tracking, coordinated tracking exercises and coordinated tactical exercises.

The US ships trained with each other in a series of anti-submarine warfare (ASW) and surface warfare exercises and focused on coordination and effectiveness of tracking and hunting submarine threats.