Trident-class ballistic missile submarine USS Pennsylvania (SSBN 735) completed a major step in its 27-month, engineered refueling overhaul (ERO) when it departed Puget Sound Naval Shipyard and Intermediate Maintenance Facility (PNS & IMF) Aug. 5. Pennsylvania, based at Naval Base Kitsap-Bangor, entered dry dock in December 2009 for its ERO, which will enable the submarine to provide another 20 years or more of service. Cmdr. Gustavo Gutierrez, Pennsylvania's commanding officer, applauded the efforts of his crew and shipyard personnel for ensuring a safe and successful undocking. "I cannot be more proud of the hard work done by my crew along with the shipyard to make this day possible," said Gutierrez.