POEL — Final preparations are underway for a millionaire-funded plan to lift a 12-tonne humpback whale nicknamed Timmy from the mud off the German island of Poel and tow it 400 kilometres toward the North Sea and back to the Atlantic Ocean. The mission, known as Operation Cushion, is scheduled to start Tuesday, more than three weeks after the whale became stranded along the Baltic Sea coastline.

The whale was first spotted in the Baltic Sea last month, possibly after chasing shoals of herring, and has been lying in the mud off Poel in Mecklenburg-Vorpommern. The water there contains too little salt to sustain the animal. Under the plan, rescuers will lift the 30-metre-long whale with air cushions and suspend it in a pontoon structure using a net, then tow the pontoon into deeper waters with a tugboat. A rescue team brought equipment to the site on Friday.

Rescue workers said that on Sunday Timmy was positioned in the right direction in the water. Environment minister Till Backhaus said: "It is interesting, it turned 90 degrees – and in the right direction. It seems to be preparing itself mentally and emotionally for departure."

Hundreds of onlookers, including tourists from across Europe, have traveled to Poel to watch the whale, with many camping nearby in cars or caravans. Several supporters swam through the sea to within metres of Timmy before being hoisted out by water police. The local fire brigade has been spraying the whale with water to keep it hydrated, individuals have repeatedly poured buckets of water over its back, and hundreds of kilograms of zinc ointment have been applied using cloths to treat wounds on its blistered skin.

The rescue group is financed by Karin Walter-Mommert, an equestrian expert, and Walter Gunz, a former co-founder of a German electronics retailer chain, who have expressed a desire to save the whale regardless of the cost. Backhaus said the pair have assumed full legal responsibility for the operation. "They have also made it clear that they claim extensive freedom of decision-making in this matter," he said.

Burkard Baschek, director of the Oceanographic Museum in Stralsund, said: "A rescue attempt is no longer worthwhile. This has also been confirmed to us repeatedly by international colleagues." He said a report compiled by his colleagues remains valid and states that Timmy's lethargic behaviour indicates serious health problems, and that a fishing net caught in the whale's mouth is thought to be still there and impossible to remove. Baschek called the police after receiving threats that included social media posts saying 'May the seagulls peck you to pieces' and 'may you suffer just like the whale'.

Backhaus has also been placed under extra police protection after receiving threats accusing him and his team of giving up on the whale too soon. "I won't be blackmailed," he said. He has denied supporting the initiative for political reasons related to an upcoming state election between the Social Democrats and the AfD.