Hi adieu,

That reef is positioned accurately on the charts of the Sulu Sea, the ships of Halsey's navy spent quite a bit of time plying those waters 60+ years ago without hitting it, after all...

Appears to be an error in the creation of the electronic chart, pure and simple:

"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."

http://www.defensenews.com/article/20130123/DEFREG02/301230026/U-S-Navy-Charts-Used-By-Grounded-Minesweeper-Safe

best regards,

Jon