• July 22, 2020

The Royal Navy was at fault in an incident two years ago when a nuclear submarine almost collided with a Stena Ferry on passage between Britain and Ireland.

The MAIB has finally published a report which found that:

“This near miss happened because the submarine’s control room team had underestimated the ferry’s speed and overestimated its range, resulting in an unsafe situation developing. However, the submarine’s control room electronic tactical display presented a picture of a safer situation than reality; this meant that safety-critical decisions made on board the submarine may have appeared rational at the time.”



The Celtic League campaigned for over three decades on this issue and logged a significant number of actual and suspected incidents involving submarines from various NATO powers.

The League campaign led directly in the late 1980s to the adoption by the International Maritime Organisation of resolutions which place the onus on submariners to avert incidents. However the Stena incident shows that both International and Domestic regulation of maritime activity by submarines in confined coastal waters and in shipping anes requires further control.

The Irish Sea is a favoured exit route for larger nuclear submarines transited to their deployment area. The confined nature of the sea and natural and manmade seismic activity make it a noisy environment and this enables the larger SSBNs to evade detection by SSNs from powers such as the Russian Federation seeking to track their deployments.

The Irish Sea has witnessed a number of snaggings and sinkings of smaller vessels but such incidents pale significantly when compared to the ‘Stena Affair’. A collision with a major ferry on this occasion was averted but there is no indication that in over four decades the submarine operating powers have learned by their mistakes;

Related link:


TV documentary mid 1980s includes interview with the Celtic League:

Image: Sub periscope photograph shows how close the submarine was to Stena ferry (pic Stena Line)

Bernard Moffatt

Assistant General Secretary Celtic League (16th July 2020)

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