The "Collins" class submarines are armed with six torpedo tubes, and carry a standard payload of 22 torpedoes. Originally, the payload was a mixture of Gould Mark 48 Mod 4 torpedoes and UGM-84C Sub-Harpoon anti-ship missiles; previously carried by the "Oberon"-class boats. In 2006, the Mark 48 torpedoes were upgraded to the Mod 7 Common Broadband Advanced Sonar System (CBASS) version, which was jointly developed with the United States Navy. "Waller" was the first vessel of either navy to fire an armed Mod 7, sinking the decommissioned "Spruance"-class destroyer on 16 July 2008, during RIMPAC 08. Some or all of the torpedo payload can be replaced with up to 44 Stonefish Mark III mines.