[6] On 16 March 1977 an IRA sniper, hidden in the grounds of a church at Omeath, County Louth, on the Republic, fired two shots at the Royal Navy patrol ship HMS Vigilant in Carlingford Lough.

Five of the group remained watching on shore, while another seven members of the ASU, carrying two high explosive charges, forced the skipper to take them to the British coal ship.

Once on board, the cell informed her captain,[13] Ian Eves,[14] about their intentions and ordered him to gather the crew and to get his men into the lifeboat.

The hijacked motor launch then took in tow the lifeboat, leaving her adrift close to the eastern shore, and headed back for Moville.

As the lifeboat reached the beach, the first explosion shook Nellie M. Huge flames, visible from several miles away, engulfed her bridge.

The attack was again launched from the pilot boat based at Moville,[16] and the IRA seaborne unit took advantage of darkness and fog.

[17] Once on deck, the IRA men ordered the second on board, David Hinson, and the captain, Roderick Black, to gather the crew onto the bridge.

[18] The coaster's lifeboat with the crewmembers was towed to the shoreline in the same way as in the case of Nellie M.[16] After the explosions, the cargo vessel sank on her starboard side in some 15 metres (49 ft) of water.

[15] One of the unexpected consequences triggered by the bombings was the debate in the Oireachtas about the dispute with the United Kingdom on the legal jurisdiction over the waterways in Northern Ireland.

[20] A bigger naval target was hit by the IRA several years later, in 1990, when an unknown number of its members managed to board RFA Fort Victoria at anchor near Belfast, shortly after her launching.

[21] One of the IRA sniper teams that operated in South Armagh in the final years of the conflict fired two rounds from a Barret .50 calibre rifle at Bird-class patrol vessel HMS Cygnet at Carlingford Lough in December 1993.