A first effort will be made on Friday to salvage the propeller lost from the Cook Strait ferry Aratere on Tuesday night.
The Interislander company says salvage specialists will use scanning equipment to survey the seabed near Tory Channel, where the propeller sank in more than 100 metres of water.
General manager Thomas Davis says options for retrieving the six tonne propeller and broken shaft will be examined after it is found.
Because of the depth, he says a remote-controlled submarine will probably be used for the salvage.
An investigation into the mishap is expected to take some months.
The company is looking at alternative vessels for the Cook Strait service while Aratere is being repaired at a dry dock overseas.