Question: What is the water depth of sanctuary which is the site of the wreck of the first ironclad warship commissioned by the union navy?
Sentence (from "Monitor National Marine Sanctuary"): The sanctuary comprises a column of water 1 nmi in diameter extending from the ocean’s surface to the seabed around the wreck of the Civil War ironclad, which lies 16 nmi south-southeast of Cape Hatteras, North Carolina.
Relevant evidence: No