Shell icebreaker Fennica struck uncharted reef, Coast Guard saysNov 30, 2016 01:58 PM
Shortly after leaving Dutch Harbor, Alaska, in July 2015, crewmembers on the icebreaker Fennica heard a loud noise they initially thought was the anchor returning to its pocket.
But over the next two hours, the chief mate noticed water rising in the 380-foot ship’s No. 4 ballast tank, and further investigation showed it was slowly flooding. Soon after that discovery, the master decided to return to Dutch Harbor, where divers found a gash in the hull.
The National Oceanic and Atmospheric Administration (NOAA) vessel Fairweather surveyed the area shortly after the incident and discovered an uncharted rock roughly 22.5 feet below the surface. Fennica’s draft was 26.25 feet at the time of the accident. With tidal conditions, the ship was about 9 inches too deep to clear the rock.
At the time, navigation charts showed the shallowest point along Fennica’s trackline was 31.5 feet. However, data used to create those charts was nearly 80 years old.
“The primary causal factor that led to the casualty is the uncharted rock pinnacle not reflected on current charts as of the date of the casualty,” Coast Guard investigators determined in a report released earlier this year. The report also acknowledged that “the vessel’s route using the current charts at the time of the casualty was sound in regard to the known depth of the water.”
Fennica provided icebreaking and oil field support services for Shell Oil. It also carried equipment to stop leaks in underwater wells. Arctia, the Finnish firm operating the vessel under contract with Shell, concurred with the Coast Guard’s findings, according to company spokesman Eero Hokkanen.
Fennica left Dutch Harbor for the Chukchi Sea at 2246 on July 2 with a pilot on board. The voyage plan called for transit between Hog and Amaknak islands. Four minutes after departing, the crew heard the sound they thought was the anchor, which had been lowered earlier in the evening.
From 2300 until 0100 the next morning, the chief mate saw the water level rising in the ballast tank and determined the vessel was taking on 4 to 8 cubic meters of water per hour. Fennica’s ballast pumps could remove 100 cubic meters per hour, but at 0145 the master opted to return to Dutch Harbor, according to the report.
Divers found a fracture 3 feet long and 1 inch wide on Fennica’s hull about 180 feet aft of the bow and 24 feet outboard of the centerline. Damage was estimated at $100,000 or less.
NOAA has begun a multi-year effort to update navigational charts in key shipping areas in the Arctic and Alaska. The project was driven in part by a surge in vessel traffic from oil field exploration, cruise ships and a potential shipping route through the Chukchi Sea.
Although the charts cited in the Fennica casualty used data from the 1930s, other charts in the region rely on data up to 150 years old. Capt. Rick Brennan, chief of NOAA’s Coast Survey Development Laboratory, said only about 1.4 percent of the Arctic has been surveyed to modern standards. These standards call for sonar mapping of the seafloor to identify objects larger than 1 cubic meter.
“There are still large areas of the Arctic that aren’t covered to that standard, and even parts of Alaska when you get farther out on the Aleutian chain that don’t have the data to back up the charts on that level,” he said in a recent interview.
Even so, the Fennica grounding was an anomaly. Brennan could not cite a similar accident near Alaska or the Arctic blamed on an inaccurate chart. But as ice recedes and shipping in the region increases, such incidents could become more common.
“In the absence of a larger survey effort, there will be a higher risk of groundings if the amount of marine traffic continues to increase,” Brennan said. “That said, we have our two largest and most capable vessels (Fairweather and Rainier) dedicated to surveying in Alaska and the Arctic. These are also our oldest vessels — currently at 47 years old — and the only vessels dedicated to ocean mapping in the Pacific.”
NOAA highlighted the rock that Fennica struck as a danger to navigation shortly after the accident. The agency updated the affected chart in March 2016 to show the new depths, and the raster chart was updated in August 2016 and released later that month.
After the accident, Fennica underwent repairs at a Portland, Ore., shipyard. The vessel is currently in Rauma, Finland, and is no longer under contract to Shell.