Inspectors from the Maritime and Coastguard Agency ruled that the crew of the Norman Voyager failed a basic test of safety procedures.
Passengers who were already on board the vessel were told to disembark after the inspection, which happened before the vessel was due to set off last night.
The ship, due to sail to Cherbourg, had been chartered from LD Lines by Celtic Link Ferries.
Inspectors were due to carry out a further inspection this afternoon and will not let the ship sail until the crew pass the tests.
A message posted on the Celtic Link Ferries website read: 'We will be resuming our service as normal on Friday the 20.11.09 leaving Cherbourg at 22.00hrs with the Norman Voyager.
'Apologies for any inconvenience caused.'
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