An LVTP-7 tracked landing vehicle splashes off the stern ramp of the maritime prepositioning shipSS PFC. EUGENE A. OBREGON. The ship is participating in the first in-stream offload exercise of a maritime prepositioning ship in the open ocean. Equipment and supplies are being unloaded from the ship by the 6th Marine Amphibious Brigade and shuttled to shore by lighter as part of exercise Solid Shield '87