UK MAIB has issued investigation report on a collision incident between the stern trawler Karen (B317) and a dived Royal Navy submarine in the Irish Sea on 15 April 2015.
The incident:
At 1605 on 15 April 2015, a dived Royal Navy submarine snagged the fishing gear of the UK registered trawler Karen, 15 miles south-east of Ardglass, Northern Ireland. Karen had been trawling for prawns on a westerly heading at 2.8 knots when its fishing gear was snagged and it was dragged backwards at about 7 knots. Karen’s crew managed to release both winch brakes, freeing the trawl warps; the starboard warp ran out completely but the port warp became fouled on the winch drum, causing Karen to heel heavily to port and its stern to be pulled underwater. Karen broke free from the submarine when the port warp parted; there was structural damage to the vessel but it returned to Ardglass safely under its own power. Evidence of the collision on board the submarine was either not observed or misinterpreted. This meant that the submarine did not render immediate assistance as the command team was unaware of the collision until about 3 hours later.
The collision occurred because the submarine’s command team assessed that Karen was a merchant vessel, primarily because no trawl noise was heard. The submarine was at a depth where it could, if necessary, pass safely beneath a merchant vessel, therefore the command team would not have perceived any risk of collision; as a result, no avoiding action was taken.
The submarine’s command team had assessed that the majority of shipping contacts in the area were merchant vessels. However, most were actually trawlers; this was predictable and should have been identified as a significant risk to the safety of the submarine and other vessels when preparing the submarine’s passage plan. Had the submarine’s command team appreciated the high density of fishing vessels and then followed Royal Navy guidance on fishing vessel avoidance, the accident would have been avoided because the submarine would have been slowed down and returned to periscope depth when the density of shipping increased.
Findings:
This investigation was conducted without the full co-operation of the Royal Navy. The involvement of a submarine was not revealed until nearly 5 months after the accident and it took 10 months for the Royal Navy to submit evidence to the investigation team. These delays impeded the progress of the independent investigation, and the evidence submitted was insufficient to determine all the causal factors.
Recommendations:
Safety recommendations were made to the Royal Navy to review the procedures and training necessary to ensure that submarine operations in the vicinity of vessels engaged in fishing are conducted safely, and to provide assurance that actions have been taken to prevent recurrence.
Further details reffering to the incident may be found below
Source & Image credit: UK MAIB
