Minister for Defence Willie O'Dea confirmed he had spoken to skipper Colm Newport who evacuated all on board when an alarm alerted the crew to a bilge full of water.
A collision with an under water object is still a possibility although a seacock failure was also a possibility.
Commandant Fergal Purcell, spokesman for the Irish Defence Forces, says French rescuers took everyone in the lifeboats to the island of Belle-Ile-en-Mer, about 15 kilometres off the coast of Brittany.
Two French coast guard vessels and two French naval helicopters helped in the rescue.
Purcell says he doesn't know what caused the ship to sink.
Raise the Asgard - Afloat's 2008 online petition
A former captain of the Asgard II, Frank Traynor, said the ship was built to survive hurricane-strength winds. He said he suspected a faulty "sea cock" - one of dozens of valves designed to permit sea water to enter the ship to cool engines or flush toilets - was to blame.