The Steam Packet Company says two sailings on Monday are under threat as bad weather approaches.
Gale force winds mean the 8am sailing to Heysham and her return trip setting off for Douglas at 1.45pm are both at risk.
A final decision is due to be made by the Manxman's master by 6am on Monday.
The company has also been forced to postpone a cruise around the Island on Sunday.
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