The vessel, the Genmar Compnaion, which is 228 metres long and 54,000 tonnes, is carrying gas oil.
The boat was located 40 miles North West of Tory Island when the crack was spotted by one of the 23 crew.
Because it is such a large vessel, Belfast is the nearest port the boat could pull into.
However the coastguard service said there is no environmental threat as a result of the incident.
Darragh O’Malley-Daly of the Malin Head Coastguard told Donegaldaly.com that there is no danger to the crew.
“As far as we understand there is no danger and the vessel is pulling into Belfast as a matter of precaution.
“It is obviously quite a large vessel. It is registered in the Bahamas.
“A crack was spotted on the deck and that will be assessed once it pulls into shore,” he said.
The boat was travelling from Rotterdam to New York when the incident occurred.