The San Francisco, you may recall, is the sub that hit an undersea mount south of Guam in 2005 and suffered pretty severe damage. One crewman was killed in the accident. A temporary bow was fitted to allow her to be sailed back to the US for permanent repairs. Due to the fact that San Francisco had recently had her reactor refueled, the Navy decided to replace the damaged forward section (see pics below) with the forward section of the recently-retired USS Honolulu (SSN 718). Honolulu was slightly newer but had not undergone refueling and was going to be decommissioned anyway.
San Francisco rejoined the fleet in the spring of 2009, but I’m not sure if this is her first post-repair deployment or not. Does anyone know for sure?
Pics of collision damage below: