When Navigating Uncharted Waters Goes Wrong

7 February 2023 By Kate Lardy
Marine chart
Credit: cronopios/iStock

Kate got her start in the yachting industry working as crew. She spent five years cruising the Bahamas, Caribbean, New England, and Central America, then segued that experience into a career in marine journalism, including stints as editor of Dockwalk and ShowBoats International.

It was a pleasant day in Sicily — calm seas, clear skies, and a gentle breeze of 6 to 8 knots blowing in from the southwest. S/Y Rock Bottom had a short passage that day with just one guest on board and a three-hour jaunt up the eastern coast. The captain drew up a passage plan and they set sail, with engine power supplementing the light wind in the sails. On deck, the guest was enjoying the sun and the views, but wanted a better look at the shoreline and asked the skipper to take the yacht closer. He obliged and headed in towards Capo Sant’Alessio while keeping the vessel in at least 20 meters of depth.

That is, until it wasn’t. The yacht came to a shuddering stop as it grounded on a shoal. It was about 70 meters offshore at the time.

It’s like the vessel took a page from the Costa Concordia disaster book. In this case, this is a lightly fictionalized account based on a real incident involving a 32-meter sloop that took place a few years ago. Four of the crewmembers suffered injuries, including one broken leg, and while the yacht did not take on water, it experienced significant damage to the hull, superstructure, and fittings — all for a closer view of the shore. The Marine Safety Investigation Unit of Transport Malta concluded that the immediate cause of the grounding was the deviation from the passage plan and the very close sailing to the coast. A contributing factor was the quality of the chart. With a 1:300,000 scale, it did not show the coastal features in useful enough detail.

“If an owner or guest says I want to go closer to land, it takes a brave captain to turn around and say ‘no,’ but it takes a good captain to say ‘give me five minutes,’” says Steve Monk, founder of Da Gama Maritime, which provides navigation management and onboard crew training for superyachts and commercial ships. “Let me analyze it…okay, the chart’s not great. What alternatives have I got? What am I going to do to err on the side of safety? And let’s slow down and watch the echo sounder very carefully.”

Monk was once a Royal Navy Specialist navigator who would spend hours going into excruciating detail to prepare passage plans, but he recognizes the reality of the superyacht industry. He knows that crew don’t have that kind of time, and he also understands owner and guest pressure. “A guest will suddenly say, ‘I know we wanted to go this way, but actually I want to go that way,’ and you’re expected to oblige,” he says. “But you must maintain safety. You have to interrogate the situation; if the chart lacks the data, that is when you have to say, ‘Let’s risk-assess it.’ I think that’s where they obviously failed in the above scenario. And that comes down to complacency.”

A common misconception when using charts, whether paper or electronic, is confusing “up to date” with “recently surveyed.”

Charts can often lack the necessary data. A common misconception when using charts, whether paper or electronic, is confusing “up to date” with “recently surveyed,” says Monk. In reality, only 24 percent of the ocean floor has been mapped to a suitable level. He points out that the only parts of the sea floor that are being surveyed today are for commercial interests, whether looking for oil and gas or laying cables, and these are not the same areas where yachts are cruising.

“A lot of crew also think that where there may be gaps between the individual spot depths on the chart, like if it says 200 meters here and it’s 200 meters over there, then it must be 200 meters all the way around it,” Monk says. Even the U.S. Navy, which has managed to run two submarines into seamounts, has made this mistake.

When official charts fall short, think about what else you have available, suggests Monk. It could be a case of, “I’ve got a plotter in my tender; it’s got better chart data quality on it, and it’s suggesting that we stay, not 70 meters offshore, but let’s go to 250 and give the guests a pair of binoculars.” And there’s always the failsafe maneuver of sending the tender ahead.

Da Gama Maritime investigated the grounding of a yacht in Madagascar, whose captain thought they were 1,500 yards from where the yacht actually was. “The datum that your chart may be operating in could be different from the signal that you’re receiving on the GPS,” Monk says.

“Now, a lot of the modern ECDIS will automatically take the GPS position from WGS 84, and they will make the conversion to whatever the chart datum is for that area. So they can merge the two,” he continues. “But if there is no known datum, the ECDIS has no idea what to base it on.” In the case of this Madagascar grounding, the captain failed to take into account the chart’s lack of datum and the extreme old age or lack of survey data.

“What you then have to do is revert back to radar,” Monk says. “If your radar says you’re here, you must be here because it’s bouncing off the land. If that doesn’t tie in with the GPS, I’d go with the radar, but I’d still start taking visual bearings to tie things in. You have to go old-school dinosaur to back up the new style GPS, even in 2022.”

After all, yachts are still running aground in 2022. As Monk says, “We just don’t hear about it in this overly secretive industry.”

This article originally ran in the September 2022 issue of Dockwalk.


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