The Aratere could become a slow boat to Singapore by the end of the year.
KiwiRail chief executive Jim Quinn confirmed last night that Singapore looked the most likely dry dock destination for the crippled ferry to have either one or both of its propeller shafts replaced.
Whether it will be towed there by a tug or allowed to go on its one propeller will be determined by classification society Det Norske Veritas and Maritime NZ. Until they are satisfied, it cannot leave port.
Its missing starboard propeller, which broke off outside Tory Channel on November 5, was found and photographed about 120 metres beneath the surface by a remote- controlled underwater vehicle on Saturday.
Once it is raised - which could be several weeks away, depending on the weather - it will be taken to the Transport Accident Investigation Commission workshop in Seaview, Lower Hutt, where it will be examined as part of the inquiry into the accident.
A metallurgist has already been commissioned to look at the broken propeller shaft.
A voyage to Singapore, on one propeller, at a speed of about 24kmh, could take three weeks. The return journey, with two operating propellers, would take about two weeks.
Quinn expected a fully operational Aratere to return from Singapore by late March or April.
"We are getting quotes for two shafts just in case we need them," he said.
"We are wanting to take the most sensible path and not spend a stupid amount of money.
"A new shaft or shafts could easily be flown to Singapore from anywhere in the world."
InterIslander officials are in Europe looking at possible temporary replacements for the Aratere.
Quinn expected a replacement could be operating on Cook Strait by some time in January, and he wanted it to remain in service while the Arahura, another of InterIslander's ferries, was scheduled for routine dry docking at Devonport next year.
Recovering Aratere's lost propeller could be a risky job, salvage company Seaworks has warned.
Chief executive Steve MacIntyre said the propeller could fall out of the lifting equipment and be lost.
The company would probably use its survey vessel Seasurveyor, the unmanned submarine and another ship in the salvage effort, he told Radio New Zealand.
- Fairfax Media