 Two boats "Collins" and "Dechaineux" received the special forces upgrade providing the capability whilst submerged to release several swimmers and for their reentry, filling a capability gap the former "Oberon"-class boat "Onslow" had provided.While the Collins class submarines' performance has improved over time, their maximum diving depth was permanently reduced following the near-loss of "Dechaineux" when a pipe burst during a practice dive in February 2003.In 1998, the Royal Australian Navy became the fourth Navy in the world to permit women to serve on board submarines.