U.S. Navy sailors prepare to refuel an Army CH-47 Chinook helicopter. U.S. Navy sailors prepare to refuel an Army CH-47 Chinook helicopter aboard the amphibious transport dock USS Tortuga (LSD 46) during a bilateral training exercise off the coast of South Korea on March 7, 2007. Tortuga is embarked with the Essex Amphibious Ready Group that is conducting the first phase of its annual spring patrol. SHARE: Download: Full Size (0.03 MB) Credit: VIRIN: 449589-L-HSE47-326.jpg Photo Gallery