"The SEA 1000 submarine program is currently in the concept design phase of development. The preliminary design phase is to get under way in 2011. Followed by detailed design in 2013, with construction to start in 2017 and the first unit to enter service in 2024. The Sea 1000 program will take place in parallel with multiple programs supporting the six current RAN Collins class submarines that will be upgraded until 2017, with the first unit scheduled to be withdrawn from service in 2025. The overlap of the two designs in service, and the challenges inherent in expanding the RAN submarine force are among the factors that will certainly influence the impending decisions on selection of a submarine design to meet the SEA 1000 requirement and what combat system and other material will be procured to equip them."