The Steam Packet company says it'll make a decision tomorrow morning about two sailings under threat of disruption.
The Manxman's 8am Douglas to Heysham sailing could be called off because of bad weather, as well as her 1.45pm return trip.
A decision is due to be made by the vessel's master by 6am.
Also under threat is her 7.15pm Douglas to Heysham crossing and 1.45am return on Friday - a decision on those will be made by 5.15pm on Thursday evening.
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