According the a nearby information plaque:
ARC by William Logan. Welded Aluminum and Steel. The form of this sculpture has been abstracted from river-going vessels and nautical moorings. Its center-of-gravity has been adjusted to give it buoyancy, enabling the sculpture to respond to the wind. Welded aluminum, steel chains and shackles reinforce the nautical vocabularly, while its form reflects Peekskill’s location on the river and the curvature of the surrounding hills. The support structure allows the “arc” to move with the breeze, tipping and feathering into the wind like a boat on a mooring, while the internal balast gives it a gently-rolling movement. The sculpture inherently indicates the wind direction, and provides a highly visible landmark designating the bend in the river at Peekskill Bay. 2014.
Taken with an Olympus OM-D EM-10 and Panasonic Lumix G Vario 14-42 f3.5-4.6 II