Jeff all those USNS ship have a security detachments of some form. Some are manned by . The USCG has powers of arrest on the high seas that the USN does not have.
APRA HARBOR, Guam (Feb. 14, 2016) Sailors assigned to the guided-missile cruiser USS Mobile Bay (CG 53) pray before a baptism ceremony. Providing a combat-ready force to protect collective maritime interests, Mobile Bay, assigned to the Stennis strike group, is operating as part of the Great Green Fleet on a regularly scheduled Western Pacific deployment. (U.S. Navy photo by Mass Communication Specialist 2nd Class Ryan J. Batchelder/Released)
PRA HARBOR, Guam (Feb. 17, 2016) Sailors count MK 76 training ordnance on USS John C. Stennis' (CVN 74) flight deck. Providing a combat-ready force to protect collective maritime interests, Stennis is operating as part of the Great Green Fleet on a regularly scheduled Western Pacific deployment. (U.S. Navy photo by Mass Communication Specialist Seaman Tomas Compian/Released)
MEDITERRANEAN SEA (Feb. 14, 2016) USS Carney (DDG 64) anchors off the coast of Crete, Greece. Carney, an Arleigh Burke-class guided-missile destroyer, forward deployed to Rota, Spain, is conducting a routine patrol in the U. S. 6th Fleet area of operations in support of U.S. national security interests in Europe. (U.S. Navy photo by Mass Communication Specialist 1st Class Theron J. Godbold/Released)
PACIFIC OCEAN (Feb. 13, 2016) Sailors aboard the guided-missile cruiser USS Mobile Bay (CG 53) fire the MK-45 5-inch gun during a naval surface fire support exercise. Providing a combat-ready force to protect collective maritime interests, Mobile Bay, assigned to the Stennis strike group, is operating as part of the Great Green Fleet on a regularly scheduled Western Pacific deployment. (U.S. Navy photo by Mass Communication Specialist 2nd Class Ryan J. Batchelder/Released)
PACIFIC OCEAN (Feb. 15, 2016) Aviation Ordnanceman Airman Dylan Williams fires a .50 caliber machine gun as Gunner's Mate 2nd Class Levi Horn and Aviation Ordnanceman Airman Donald Woods look on during a live fire exercise aboard amphibious assault ship USS Boxer (LHD4). More than 4,500 Sailors and Marines from Boxer Amphibious Ready Group and embarked 13th Marine Expeditionary Unit (13th MEU) are transiting the Pacific Ocean en route to the U.S. 5th and 7th Fleet areas of operations. (U. S. Navy photo by Mass Communication Specialist Seaman Eric C. Burgett/Released)