Australia agreed to jointly develop, with the U.S. Navy, a new version of the Mk 48 torpedo. Australia is currently using the Mk 48 Mod 4, the new version will be Mk 48 Mod 7. Specifications for the mod 4 include a range of 38 kilometers at 99 kilometers an hour, or 50 kilometers at 72 kilometers an hour. It is thought that the Mod 7 will include improved sonar and electronics without adding additional weight. Australia uses the Mk 48 in its six new Collins class subs, which have been plagued by cost overruns.