NorthLink has again warned of possible disruption due to weather.
The freight vessel Hildasay, currently sailing to Aberdeen, is facing a tight turnaround.
She is only due to arrive at her destination at 5pm tonight [Saturday].
NorthLink says the vessel will head back towards Lerwick as soon as loading operations are completed.
She is expected to get back to Shetland at around lunch time tomorrow.
Meanwhile, the Helliar may be subject to delays of up to one hour on her south-bound voyage to Orkney and Aberdeen.
And the south-bound sailing of the Hrossey may also be subject to minor weather-related delays.