Ongoing engine maintenance problems at the Steam Packet have hit day-trippers.
The company is running two trips to Fleetwood on Saturday, but slower crossing times mean services will be departing from the Isle of Man earlier than scheduled.
The morning sailing from Douglas will leave at 6am, 45 minutes before the scheduled time, and the evening boat will set off from the Island at 6pm.
Both return crossings will be at the advertised times.
Steam Packet chief executive Mark Woodward is apologising for the longer crossing times, but says they cause the least disruption to passengers by avoiding the need to cancel sailings.
The changes are necessary to ensure the services coincide with the tides at Fleetwood.