Back Beach, New Plymouth, New Zealand

Around 30 Velella Velella found scattered along a half mile section of beach. Most had a diameter of 2 inches. A few were 0.5 of an inch. From looking at the photos I took, most appear to have been "Right" oriented, with the sail going from top right to bottom left.
Sandy beach with some rocky areas. They were mostly located near the rocky areas.
Had never seen these before and initially thought they were a type of blue bottle.