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US Navy says human error main reason for USS Connecticut grounding

USS Connecticut grounding
Illustration: USS Connecticut (SSN 22) getting underway from Naval Base Kitsap-Bremerton for its 2021 deployment. Photo: US Navy

The US Navy has released an investigation into the grounding of the Seawolf-class attack submarine USS Connecticut (SSN-22), identifying an accumulation of unit-level errors and omissions as the main cause of the grounding.

USS Connecticut grounded on October 2, 2021, on an uncharted seamount while operating submerged in a poorly surveyed area in international waters in the Indo-Pacific region.

The grounding damaged the submarine, removed it from operational tasking for a significant period of time, and resulted in 11 injuries.

Following the collision, the submarine transited to Guam under its own power, for initial inspections and repairs. The boat is now at Naval Magazine Indian Island, Washington.

The investigation determined the grounding was preventable. Specifically, the grounding resulted from an accumulation of unit-level errors and omissions in navigation planning; watch team execution; and risk management, “all of which fell far below US Navy standards.”

While heavily redacted, the investigation documents reveal that USS Connecticut was involved in another allision six months before the grounding. The allision with the pier took place on April 14, while Connecticut was mooring at Naval Base Point Loma. An investigation into that mishap also determined the submarine’s command was at fault.

When it comes to the October grounding, the documents show that the crew of the Connecticut did not properly mark navigation hazards at the time of the grounding. They also ignored inconsistencies between the soundings and the charts provided.

In addition to addressing the unit-level errors that caused the grounding, the investigation highlighted specific areas for improvement in the deployment training and certification process – and the Navy is urgently implementing these improvements across the Submarine Force. This investigation delineates 28 corrective actions, of which 14 actions are complete, 13 actions are in progress, and 1 action is enduring.