A damaged stabilising fin means the Ben-my-Chree is to go into dry dock twice in the next few weeks.
The first period, January 17-20, will see the fin removed and sent away for repairs, with it scheduled to be put back on during the second period, February 8-10.
During those times the Manannan will cover passenger sailings and carry some freight.
The freighter the Steam Packet will use from April, the MV Arrow, has also been secured to do an extra freight trip on both of those weekends.
Steam Packet Chief Executive Mark Woodward:
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