Bad weather has caused delays to two of the Manxman's trips.
Her 7.45pm trip to Heysham will now depart at 9pm and 2.15am return journey will set off at 4am.
Steam Packet Company says also at risk are her 8.45am Heysham and 2.15pm Douglas sailings on Wednesday.
The ship's master will make a final decision on those crossings by 7am tomorrow.
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