Strand jack silhouette
The sun rises behind the catamaran barge at the Olmsted Dam construction project on the lower Ohio River. Shown are the strand jacks atop the barge. Strand jacks are hydraulically operated lifting devices, capable of lifting extremely heavy loads. There are 12 strand jacks on the catamaran barge that can be rearranged depending on the item that is being lifted. (U.S. Army Corps of Engineers photo by Capt. Chelsey O'Nan). Original public domain image from Flickr