Angus Macleod said he and his four crew were “extremely lucky” to survive the incident in which his net was dragged in front of his 62ft trawler.
In recent months it has been alleged that Russian submarines have been operating in British waters and defence analyst Tim Ripley said a Russian submarine could be the culprit.
The Royal Navy said there were no British or Nato submarines in the area at the time.
Father-of-two Macleod, 46, from Barra has now lodged an incident report with the Maritime and Coastguard Agency and the Marine Accident Investigation Branch.
Last Tuesday, Macleod’s crew were fishing for haddock, monkfish and skate aboard the 41-year-old wooden Aquarius, about ten miles east of the Butt of Lewis in 360 feet of water.
They had two nets out when at around 7pm, and 11.30pm the boat suddenly slowed down. On the second occasion the port net moved in front of the boat, while the other continued to lay astern.
Macleod said he was baffled by what was happening and had to “up the revs” on the engine to try to keep ahead of the net for fear of it becoming entangled on the propeller.
During 15 anxious minutes, the boat was constantly manoeuvred to get in front of the moving net only for it to go forward again.
“It kept going forward and we had to repeat the manoeuvre four times to stay ahead. The winch became increasingly under strain as we tried to haul the rope. There was no way the net was snagged on the bottom – we were fishing well off the bottom. It only ended when the dog rope, which attaches the top and bottom ends of the net, was cut by the propeller,” said Macleod.
“I have been at sea for 30 years – and between the five of us there is 110 years’ experience – and we have never experienced anything like that. The sea conditions were good. We were mystified – we just couldn’t explain it.”
On heading to Stornoway, the Aquarius hit problems with its steering three miles south east of Chicken Rock and Stornoway Lifeboat was launched. It towed the stricken craft to Stornoway for repairs.
It was then discovered that four of the five one-inch bolts that connect the steering motor with the rudder had come out and the other was loose from the strain of the ordeal.
“I think that something got hold of the dog rope and the trawl wire. The only explanation I can think of is a submarine. It missed the nets, which is just as well. All five of us are extremely lucky. I don’t even want to think of what could have happened,” said Macleod.
“I have reported the incident and have at this stage been given conflicting information. At first the Coastguard told me there was submarine activity in the area – and then later the MoD told them that there was not. I would like to get to the bottom of it. It was a very worrying experience. It shook us all up especially when we thought about it afterwards. Whatever happened involved a moving object in mid-stream.”
A spokesman for Stornoway Coastguard said: “We are aware of the incident and can confirm that reports have been submitted. We are taking the matter seriously. The MoD has told us that there was no submarine activity in the area at the time. But we are continuing to investigate.”
In January it was reported that the Ministry of Defence was forced to request US military assistance to track a suspected Russian submarine off the coast of Scotland.
A similar incident in 1990 saw four crew die when a Navy submarine dragged a Scottish fishing boat under in the Irish Sea.
SCOTSMAN TABLET AND MOBILE APPS