The idea of finding the wreck of Titanic, and even raising the ship from the ocean floor, had been around since shortly after the ship sank. No attempts were successful until 1 September 1985, when a joint American-French expedition, led by Jean-Louis Michel (Ifremer) and Dr. Robert Ballard (WHOI), located the wreck using the side-scan sonar from the research vessel Knorr. It was found at a depth of 2.5 miles (4 km), slightly more than 370 miles (600 km) south-east of Mistaken Point, Newfoundland at 41°43′55″N 49°56′45″WCoordinates: 41°43′55″N 49°56′45″W, 13 miles (21 km) from fourth officer Joseph Boxhall's last position reading where Titanic was originally thought to rest. Ballard noted that his crew had paid out 12,500 feet (3,810 m) of the sonar's tow cable at the time of the discovery of the wreck, giving an approximate depth of the seabed of 12,450 feet (3,795 m). Ifremer, the French partner in the search, records a depth of 3,800 m (12,467 ft), an almost exact equivalent. These are approximately 2.33 miles, and they are often rounded upwards to 2.5 miles or 4 km. In 1986, Ballard returned to the wreck site aboard the Atlantis II to conduct the first manned dives to the wreck in the submersible Alvin.