Push comes to pull on hybrid Scandlines ships

The Copenhagen-based ferry operator said early this year it planned to replace the Rolls Royce Azipull 120 FP push thrusters on its four Puttgarden-Rødby Germany-Denmark ferries from autumn. In operation for more than 20 years, the Azipull models are being replaced with Contaz 35 azimuthing contra-rotating units from Kongsberg Maritime, of which Rolls-Royce Commercial Marine has been a part since April. The new propellers are 3200mm in diameter and each has four blades and weighs 25 tons, Scandlines said.

Schleswig-Holstein is the first to get its four new thrusters – one at each ‘corner’ – during conversion at Polish shipyard Remontowa in Gdansk. The other three 142m hybrid ferries on the route will all undergo the same conversion work during 2020 at the same yard.

Scandlines spokeswoman Anette Ustrup Svendsen told The Motorship Deutschland would go to Remontowa in March, Prins Richard in April and Prinsesse Benedikte in September – each for three weeks.

Kongsberg explained that with the older push-thrusters, the propeller was at the back, so water needed to pass the thruster before it reached the actual propeller. With high-tech pull-thrusters the propeller was at the front allowing a more homogeneous water flow, it said. Underwater noise and vibrations were also reduced significantly with the new pull- thrusters, an area of concern to wildlife organisations, Kongsberg noted. Finally, tests indicate that with the new thrusters CO2 emissions can be reduced by 10-15%.

During the yard work on Schleswig-Holstein, the hull around each thruster plant was slightly modified to optimise water flow to the propeller. The thruster drive control system on the bridge was swapped for Kongsberg Maritime’s new MCON remote control system and one of the ferry’s gensets was replaced with a bigger 4950kW unit to enable the ship to operate with just one instead of two generators. Small maintenance works were also carried out and the owner’s simulator in Puttgarden had been upgraded.

Svendsen told The Motorship the other ships being converted in 2020 would also undergo minor maintenance while in Poland. She added however that they already had the bigger gensets just installed on Schleswig-Holstein. Two of those units came from Scandlines’ two biggest 169.5m ferries Berlin and Copenhagen before they were converted from conventional to hybrid operation.