Profits at parent firm Irish Continental Group (ICG) halved to just shy of €30 million for the six months to June 30, ICG revealed on Thursday (August 30).
Chairman John McGuckan said the results were hit by cancellations caused by delays in delivery of its new ferry, W.B. Yeats.
Ulysses, meanwhile, required an unscheduled dry dock to address a problem with its starboard pitch propeller, reducing the Irish Ferries fleet during the summer peak season.
The two issues, said McGuckan, had conspired to limit summer sailings, down 102 to 2,428 on last year, hitting trade.