Manannan could carry out an overnight service to Heysham tonight - if repair work on the Ben-my-Chree isn't completed.
The Steam Packet Company says it's a contingency as engineers work to fix a technical issue caused by a failed cylinder head-securing stud.
The stud has fractured leaving a section in the engine block which has to be removed prior to the replacement being fitted.
However the company says the removal of it is "difficult and time consuming" so it's had to bring in a specialist contractor.
Chief executive Mark Woodward says he still remains "hopeful" that the Ben-my-Chree will be back in service tonight although admits there may be a "small delay" if so.
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