currents negated attempts by divers to investigate. Retired Rear Admiral Edward Ellsberg proposed using external pontoons to raise the wreck in 1951, the same method of marine salvage he had used on the sunken submarine , for the cost of $250,000. Four years later, Robert F. Marx claimed to have discovered the wreck based on the idea she had drifted into shallow water north of the lighthouse before sinking. Marx said he had dived on the wreck and placed a Coke bottle with his name on it in one of the gun barrels, although he never provided any proof of his story. Interest in locating the ship revived in the early 1970s and Duke University, the National Geographic Society and the National Science Foundation sponsored an expedition in August 1973 to search for the wreck using a towed sonar system. The Duke team was led by John G. Newton (no known relation to the Isaac Newton that served on the Monitor). On 27 August, Monitor was discovered almost 111 years after sinking, near Cape Hatteras at coordinates . They sent a camera down to photograph the wreck, but the pictures were so fuzzy as to be useless; on a second attempt the camera snagged something on the wreck and was lost. The sonar images did not match what they expected the wreck to look like until they realized that the sinking vessel had turned over while descending and was resting at the bottom upside down. The team announced their discovery on 8 March 1974. Another expedition was mounted that same month to confirm the discovery and the research submersible Alcoa Sea Probe was able to take still photos and video of the wreck that confirmed it was Monitor. These photos revealed that the wreck was disintegrating and the discovery raised another issue. Since the Navy had formally abandoned the wreck in 1953, it could be exploited by divers and private salvage companies as it lay outside North Carolina's territorial limits. To preserve the ship, the wreck, and everything around it, a radius was designated as the Monitor National Marine Sanctuary, the first U.S. marine sanctuary, on 30 January 1975. Monitor was also designated a National Historic Landmark on 23 June 1986. In 1977, scientists were finally able to view the wreckage in person as the submersible Johnson Sea Link was used to inspect it. The Sea Link was able to