Vessel had been using just three after a control system fault
The Steam Packet Company has confirmed the Manannan is now running on all four engines.
The fastcraft had been using just three of its engines after a problem was detected with the control system in one engine over the weekend.
It meant passengers had been facing longer than usual crossing times over the last few days.
The vessel is now expected to run to schedule on its two round trips to Liverpool today.
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