Scores of passengers were sick during Sunday's Channel crossing from Weymouth to Jersey via Guernsey.
And some reported fearing for their lives during the turbulent trip.
The company is now facing compensation claims from the vehicle owners affected.
'At the time Vitesse set sail, wave heights were within externally set safe limits and this remained the case throughout the journey,' said Condor Ferries ports and guest services director Captain Fran Collins yesterday.
'The vessel was prepared for sea in accordance with all company procedures for heavy weather. However, as the vessel approached the waters around Casquets Lighthouse a patch of unforeseeable and highly localised high waves developed, aggravated by tidal conditions in the area, which caused the vessel to move heavily.'
She added that the ship's master immediately reduced the vessel's speed to minimise the impact from the high waves but by then damage had already occurred.
