I saw this Coast Guard ship outside Kawaihae harbor. Here, it was hauling out one of the buoys marking the entrance to the harbor for inspection and maintenance. Buoys like this are commonly seen in coastal areas, in the vicinity of ports. They help guide ships into harbor, marking safe, deep channels or shoals to be avoided.
From shore, these buoys look like little green and red floats, but anyone who has ever been in a small boat being swept toward a buoy by a surging current knows better. Up close, they’re a big chunk of metal that you run into at your peril. In the photo to the right, the figure next to the buoy being hauled aboard gives some idea of the scale.