NTSB has published an investigation report into an incident involving the sinking of the industrial vessel Cape Douglas near Kodiak, Alaska in November 2024.
The incident
On November 6, 2024, at about 12:55 local time, the industrial vessel Cape Douglas was transiting Chiniak Bay, about 4 miles southeast of Kodiak, Alaska, when the captain observed flooding in the engine room. Unable to control the flooding, the captain and crewmember abandoned the vessel into a towed skiff and were rescued by a Good Samaritan vessel. There were no injuries. The vessel later sank with an estimated 400–600 gallons of diesel fuel on board. It was not recovered and was a total loss, valued at $250,000.
Analysis
While the Cape Douglas was operating as a fish tender, transiting Chiniak Bay about 4 miles southeast of Kodiak en route to dispose of fish byproduct, the captain discovered flooding in the engine room. The captain and deckhand were unable to control the flooding and abandoned the vessel into a towed skiff before being rescued by a nearby Good Samaritan vessel; the Cape Douglas ultimately sank.
Photos from a 2022 survey of the Cape Douglas showed evidence of rust and deterioration below deck in the engine room and passageway. The passageway housed the sea chest and associated pump, valves, and piping for the deck washdown system used to flush overboard the fish byproduct in the vessel’s fish bins. Audio gauge hull testing revealed wastage greater than 25% in multiple areas of the vessel’s 0.312-inch-thick bottom plating, including along the port side near the deck washdown system components.
Coast Guard guidance generally allows for 25% corrosion in steel plating but specifies that for converted landing crafts originally built to less than commercial scantlings (0.375 inches or less), the plating should generally be replaced when wasted more than 15%. About seven months before the sinking, the City of Kodiak harbormaster had raised concerns about the vessel’s condition.
The vessel’s age (80 years old), visual signs of rust and deterioration, and documented hull wastage suggest a general degradation of the vessel and onboard systems, such as the deck washdown system. However, because the vessel was not salvaged, investigators could not determine the condition of the components of the deck washdown system, including the inlet valve between the sea chest and the seawater pump, the pump, or the associated piping. Based on the captain’s statements, these components were over 25 years old and had not been used or tested for at least two years before the sinking. On the day of the sinking, the system was not tested before getting underway, so the captain would not have identified any issues with it.
As the Cape Douglas neared the disposal site, the captain did not observe any flooding below deck while opening the inlet valve for the seawater pump and attempting to start the pump. The flooding was only observed when he returned to the engine room about 15 minutes after opening the valve. Because the flooding occurred shortly after the valve was opened, it was likely caused by a failure of the deck washdown system piping or components downstream of the open valve.
While the Cape Douglas was equipped with watertight doors in the engine room and companionway spaces, these doors remained open during the transit. Maintaining watertight integrity is a fundamental principle of safe operations on water. Within the hull, watertight bulkheads and doors are designed to prevent progressive flooding by containing incoming water to the compromised space. Had the watertight doors for the engine room, passageway, pump room, and sea chest room been secured, they may have contained the flooding.
Conclusions
Probable Cause
The National Transportation Safety Board determines that the probable cause of the sinking of the industrial vessel Cape Douglas was flooding of a below-deck passageway or the pump room from an undetermined failure in the vessel’s deck washdown system. Contributing to the sinking were open watertight doors, which allowed progressive flooding into the engine room and other below-deck spaces.
