Electronic charts are not foolproof

On the rocks may be great for scotch, but it’s bad for boats. On Jan. 17, the USS Guardian, a Navy minesweeper, hit a reef in the Philippines

The Navy said the electronic charts used on the Guardian had an error in the reef’s charted location. The investigation will probably reveal other issues regarding the ship’s navigation and watchstanding. The error was supposedly introduced when the chart makers digitized the chart. The ship is a total loss and the Navy has said it intends to cut the 1,312-ton Guardian up to be barged off and scrapped.

Those “bump and go” river sand groundings aren’t necessarily a big deal. That’s unless you bump the rocks the Corp of Engineers have been blasting away on the Mississippi River. Ground your vessel on less forgiving bottoms like reefs and wrecks, and you’ll be in trouble.

This blog is more for the salt water and big fresh water mariners. Still, all mariners find that poor navigation and lax watchstanding is often the root of many tragedies.

Navigation errors can have their seeds in false confidence and overreliance on a single system or means used to fix your position. No one source should be used for navigation. Navigational accuracy and your proximity to dangers would then completely depend on that sole system. Electronic navigation systems are not infallible. Relying only on GPS and chart plotters as the color video version of God’s given truth can be dangerous. The waterfall of electronic charts bores you into a wicked complacency. You forget that the wheelhouse has windows.

Government rocket science advertises a GPS margin of error of several tens of meters, including holes in coverage. Overlay that on a paper chart from Captain Cook’s era, circa 1775, which are perhaps the most recent charts for the waters around the Tubbataha Reef where the Guardian got stranded, and you are standing into danger.

Look around the wheelhouse. You’ll probably see two radars, two GPSes, a pair of VHFs, an AIS, a fathometer, a chart plotter, electronic charts and hopefully paper charts. These are even seen on some river towboats. Add windows and binoculars, and don’t forget the Coast Guard’s required publications.

Those are a lot of tools that can be used for situational awareness in comparing tracks, fixes, and positions. Use them all. If you are running a routine route and think you know the chart like the back of your hand, you are on a fool’s errand. Ferry and tour boat operators keep learning that the hard way — shoals change, buoys move, new wrecks pop up.

With all the advances in navigational equipment, there still is not an electronic version of common sense.

Sail safe!

Editor’s note: The Navy contracted the DP crane vessel Jascon 25 on Friday as salvage work on the Guardian began. Using its DP system, the Jascon 25 can position its crane within reach of the Guardian without requiring mooring equipment that could damage the reef.


Check out an interview with Adm. Cecil Haney on the Armed Forces Network after he met with the crew of the Guardian at Sasebo Naval Base in Japan.


About the author

Capt. Peter Squicciarini

Capt. Peter Squicciarini is a licensed master mariner and marine safety specialist at the U.S. Coast Guard Atlantic Area Command in Portsmouth, Va. He has worked on towing, passenger, and fishing vessels, and was a safety and compliance manager for an East Coast tug and barge company. He also served in the Navy as a surface ship officer and commanded several warships. He can be reached at pdsquicciarini@msn.com.

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