While a review of the digital navigation charts (DNC) used by a U.S. Navy minesweeper that grounded last week in the Philippines found one additional error, the charts were declared safe Wednesday by the Navy’s top navigator.
“Ships should continue to confidently navigate with DNC, using all standard safe seamanship and navigation practices,” Rear Adm. John White, navigator of the Navy, said in messages sent Jan. 23 to Navy ships, commands and flag officers.
The National Geospatial-Intelligence Agency (NGA), creator of the charts, conducted “a comprehensive analysis of all DNC libraries,” White said in the message, and confirmed the error in the location of the Tubattaha Reef in the western Philippines, which the minesweeper Guardian struck in the early hours of Jan. 17.
The NGA reported earlier the location of the reef on the DNC charts was about eight nautical miles away from its true location.
“Additional significant errors” — up to four nautical miles — were found along the southwest coast of Chile, White reported in his messages. Those errors, he wrote, “are reflected on DNC and paper charts. NGA has issued warnings on those errors to all mariners.”
The two inaccuracies “are the only known significant errors in the entire DNC portfolio of over 3,700 libraries,” White wrote.
“No chart is infallible, but NGA’s DNC remains the most accurate chart portfolio available.”
The errors that were found came from the LANDSAT satellite survey images used to “geo-rectify” the digital charts, White wrote.
“Navy will be a key participant in a follow-on review of NGA’s procedures to ensure the products and services associated with nautical charting continue to be safe and accurate,” White said in the messages.
“I share NGA’s high confidence that these errors are isolated, and that DNCs are overall safe for navigation.”
U.S. Navy: Charts Used By Grounded Minesweeper Are Safe | Defense News | defensenews.com