Puget Sound Naval Shipyard and Intermediate Maintenance Facility (IMF) are seeking shipyard volunteers to help overcome a staffing shortage of more than 600 mechanics, a result of the Navy-mandated hiring freeze. Despite being exempt from Defense Department-wide employee furloughs, Puget Sound Naval Shipyard and IMF is struggling to minimize the hiring shortfall on planned availabilities for the submarine USS Jimmy Carter (SSN 23), the Trident ballistic missile submarine USS Kentucky (SSBN 737)…