The Steam Packet Company has cancelled two sailings in the face of bad weather.
The Manxman's 7.45pm Douglas to Heysham sailing and her return trip at 2.15am have both been called off.
Two sailings tomorrow are also at risk - the 8.45am crossing from Douglas and 2.15pm return from Heysham.
A decision on those is expected to be made by 7am on Tuesday.