Inspections were due to be carried out today on a tanker carrying a hazardous cargo of oil that had to be re-routed as a precaution to Belfast.
The vessel, Genmar Companion, had been en route from Rotterdam to New York when the captain contacted the Irish Coastguard to report a suspected crack in the hull.
The 228m-long tanker, which was carrying a 54,000-tonne load of vacuum gas oil, was halted 25 miles off Tory Island before beginning its journey to Belfast where repair work was due to take place this morning.
A spokeswoman for the Northern Ireland Coastguard said there were no concerns for the safety of the 23 crew members on board.
“The tanker was able to make its own way using its own power,” she told the Belfast Telegraph.
“It is coming into a port of refuge, which may sound dramatic, but actually means more sheltered waters so that a surveyor can go on at first light in the morning.
“That will probably happen at about 7am.
“There is no undue concern for the safety of the vessel or its cargo.”
The Irish Coastguard said a crack had been spotted running along the deck during inspections in Rotterdam but the vessel was deemed safe to put to sea.
Denis Moloney from Malin Head Coastguard said the decision to travel to Northern Ireland was taken as a precaution.
“There are no leaks on the vessel, and it is a precautionary measure to go to Belfast,” said Mr Moloney.
Concerns were also raised over potential weather conditions.
The vessel is about 40 nautical miles north-west of Malin Head.
However, the Irish Coastguard added: “Weather in the area is fine with force four winds and a 2m swell.
“Visibility is also reported to be good.”
Meanwhile, an Irish Air Corps aeroplane sent to the scene to monitor developments and a naval vessel were stood down after the cargo ship was granted permission to berth at Belfast.