At that depth, there was a danger of losing the remote operated vehicle because of the lack of buoyancy, which forced its operator to thrust the vehicle upward.

“During this dive, our deepest yet, we encountered challenges that impacted our ability to operate and obtain the typical, high quality survey that we strive for,” said Paul Mayer, a pilot of the remote operated vehicle and researcher.

The underwater survey was conducted by Vulcan Inc., the RV Petrel’s owner and operator, which released video footage of the wreckage last week to coincide with the 75th anniversary of the U.S.S. Johnston’s sinking and to try to get confirmation that it was the destroyer that was discovered.

The private company was started by Paul Allen, a late Microsoft co-founder, and his sister, Jody Allen, to handle the family’s business and philanthropic activities, including underwater research.

More than 30 sunken warships have been discovered by Vulcan researchers, including a number of American vessels lost in World War II, like the U.S.S. Indianapolis, the U.S.S. Wasp and the U.S.S. Hornet.

So few photos remain of the U.S.S. Johnston, according to Admiral Cox, who said both the Johnston and the Hoel performed with extreme heroism during the Battle of Leyte Gulf.