A ship last used by the U.S. Air Force to track missiles and spacecraft will soon become the world’s second-largest intentionally sunk artificial reef. Officials hope it will attract fish and divers and relieve recreational pressure on nearby natural reefs. The project has been years in the making. The cost is about $8.6 million, from acquiring the ship to cleaning it. Officials in the Florida Keys expect it to pay dividends, up to $8 million in annual tourism-related revenue, mostly from divers flocking to get a look at the underwater spectacle and related businesses. The idea is to not...