The tugboat Cingluku and its barge Jungjuk sailed toward Shakmanof Cove on Alaska’s Kodiak Island at about 10 knots on a clear spring morning. Without warning, the barge grounded on a rocky shoal a foot or two below the surface.
The articulated tug-barge (ATB) unit remained stuck against the rock some 400 yards from shore for four hours, until the rising tide lifted the barge off the shoal. There were no injuries or pollution during the incident, which happened at about 1047 on May 25, 2023, but Jungjuk required $1.5 million in repairs.
National Transportation Safety Board (NTSB) investigators determined the captain failed to identify the rock on electronic navigation charts during route planning into Shakmanof Cove. “Contributing was the captain not using all available navigational resources, including the Coast Pilot and the grounding avoidance features of the electronic chart system, when planning the route,” the NTSB said in its report.
The tugboat captain, who was not identified in the report, initially claimed to the U.S. Coast Guard that the shoal was uncharted. However, five days after the incident, he revised his statement and acknowledged he just did not see it noted on the electronic chart, according to the captain’s interview with investigators.
The 1,800-hp triple-screw tugboat Cingluku and the 185-by-55-foot Jungjuk entered service following delivery in 2022 from Halimar Shipyard in Morgan City, La. The tug is powered by three Caterpillar C18 engines with two MER 99-kW generators driven by John Deere engines. The tugboat and barge pair up through a JAK-200 coupler system. Brice Marine of Fairbanks, Alaska, owns the vessels.
The incident voyage began early on May 22, 2023, when the ATB departed Togiak, Alaska, for Seward, located about two hours south of Anchorage by car on the Kenai Peninsula. The vessels would make an intermediate stop in Shakmanof Cove to drop off supplies for another vessel, the NTSB said in its report.
The initial voyage took the ATB south through False Pass, near Unimak Island, and then east toward Kodiak Island. The captain assumed the navigational watch at 0600 on May 25 after conducting a navigational assessment with the mate. The ATB was turning into Shakmanof Cove when the barge hit the rock at 1047.
“The captain stated that the rock was not visible from the wheelhouse, nor did it appear on radar. The tug did not contact the rock and remained coupled to Jungjuk,” the NTSB report said.
The ATB floated free at about 1500, and crew determined the hull did not breach. The ATB remained in Shakmanof Cove for two more days until a weather window opened for the vessels to complete the voyage to Seward, which they did without incident.
The NTSB investigation largely focused on what information was available to the captain and crew and how they used that information as they planned their voyage into Shakmanof Cove. The cove is in a remote section of Kodiak Island north of the city of Kodiak near the village of Ouzinkie.
According to the report, the vessel had a Rose Point Navigation electronic charting system (ECS) that crew used for route planning and navigation. The system has multiple layers of collision avoidance functionality. One relied on crew to input the vessel draft or contour depth into the system, which would in turn alert them to potential hazards along the route.
According to the NTSB, crewmembers rarely used the contour depth feature on the ECS due to unreliability of soundings data in remote corners of Alaska.
Another system, known as the isolated danger setting, displayed charted hazards from data on electronic navigation charts. These hazards displayed as a magenta-colored X symbol, or plus sign, depending how one views it.
NTSB investigators tried to replicate the settings crew aboard Cingluku used during the incident voyage. When reviewing the electronic chart for the entrance to Shakmanof Cove, the magenta symbol appeared atop the rock’s charted location. However, they later learned the isolated danger symbol on Cingluku’s ECS has been disabled — something the crew said had been in place since the vessel’s delivery about a year earlier.
“When investigators disabled the isolated danger symbol feature in the ECS settings, the (magenta) symbol did not appear over the rock that the ATB struck, regardless of the entered safety contour depth value or vessel draft,” the NTSB report said. “When the isolated danger symbol feature was enabled, the isolated danger symbol appeared over the rock that the ATB struck, regardless of the entered safety contour depth or vessel draft.”
Even without the advanced collision avoidance functionality, the electronic navigation chart for Shakmanof Cove used an asterisk to mark the shoal’s location. The captain, who had close to 30 years of maritime experience and nearly 20 as a licensed mariner, acknowledged that he just missed it. The charted rock also appeared in United States Coast Pilot 9, which was aboard Cingluku, but crew did not consult the publication during route planning into Shakmanof Cove.
“The captain … told investigators that he was not aware that certain grounding avoidance features of the ECS were disabled on the day of the grounding — including the isolated danger symbol feature.”
“Using other available resources, such as the Coast Pilot, would have helped the captain in identifying the rock when planning and reviewing the route,” the NTSB report continued.
During an interview soon after the incident, investigators acknowledged the captain’s “extremely clean record” during his career moving cargo into remote parts of Alaska.
Brice Marine’s Safety Management System for Cingluku did not require crews to use one navigational chart format or another, the report said. It also did not require crews to input specific details, such as vessel draft or contour depths into its ECS during voyage planning. According to investigators, the company offered ad hoc tutorials on the ECS system but no formal training program. “Therefore,” the report said, “the crew did not use the ECS functions that could have helped them identify the rock’s location, nor did the company ensure they used or understood these functions.”
Attempts to reach Brice Marine for comment were not succesful by press time in mid-October.