Rig's transport Hawk due to arrive off Lewis on Tuesday
A ship that will transport the rig Transocean Winner to Turkey is expected to arrive in Broad Bay, Lewis, where the structure is anchored, on Tuesday.
Offshore Heavy Transport's vessel Hawk is already in Scottish waters having taken another rig to an anchorage in the Cromarty Firth in the Highlands.
Transocean Winner is to be floated on to the deck of the semi-submersible ship.
The operation could take a number of days to complete.
Hawk is a ship designed to move rigs and other large marine structures over long distances.
The 17,000-tonne drilling rig Transocean Winner is anchored off the east coast of Lewis.
It ran aground at Dalmore, near Carloway, on the west side of the island in a storm in August.
It was being towed from Norway to Malta, from where it was to be moved to Turkey to be scrapped, when it and the ship towing it were hit by a storm off the Western Isles.
The tow line broke and the rig ran aground on the beach at Dalmore.
It was later moved off the beach and towed to Broad Bay where it awaits transport to Turkey.
A number of small tugs will be involved in an operation to float it on to the Hawk.