It seems a shame, but a Union monitor survived into the 20th century, 1908,when it was sold and scrapped. Too bad someone did not have the foresight to save it at the time.
That ship would be the USS Canonicus, 1864 to 1908. She was put on display at the 1907 Jamestown Exhibition and scrapped the next year. She was the name ship of her class of nine monitors weighing in at 2100 tons. Built in Boston,Massachusetts and commissioned in April 1864 and served in the James River and was at Fort Fisher.
From March 28, 2008, http://edisoneffect.blogspot.com This had three good photos of the ship as well.
Too Bad, Too Late. --Da B-R