NorthLink has warned of further disruption to its Thursday night sailings.
Passengers travelling on the MV Hrossey from Aberdeen tonight may only arrive in Kirkwall two hours later than scheduled.
Tonight’s MV Hjaltland sailing from Lerwick is expected to be unaffected.
Both of the freight sailings could be subject to delays, however.
NorthLink said the MV Helliar may be subject to some delays in her arrival into Aberdeen Harbour tomorrow (Friday), while the MV Hildasay may arrive into Lerwick three or four hours later than scheduled.