Digital Map Error May Have Led to Minesweeper Grounding
A digital chart used by the minesweeper USS Guardian to navigate Philippine waters misplaced the location of a reef by about eight nautical miles, and may have been a significant factor when the ship drove hard aground on the reef on Jan. 17.
As of Jan. 18, U.S. Navy ships have been directed to “operate with caution” when using similar electronic charts and compare the map data with paper charts, which are considered accurate.
The Guardian drove onto Tubbataha Reef in the Sulu Sea around 2:25 a.m. on Jan. 17 (some sources cite a date of Jan. 16, since that was the date in Washington, D.C. when the incident occurred). The reef is about 80 miles east-southeast of Palawan Island.