In 2023, the ferry ‘Krk’, operated by the Croatian state-owned Jadrolinija shipping company, was retrofitted to cope with a new route, which is prone to stronger winds and currents.
For example, the open propellers of the ferry’s thrusters were replaced with new optimised propellers and fitted with Schottel VarioDuct SDV45 nozzles.
This thruster upgrade comprised overhauls and modernisations in accordance with the time schedule of the vessel’s planned maintenance cycle.
The entire retrofit process took place during the annual lay days between seasons. The thrusters were dismounted and reinstalled in Croatia by Schottel’s partner, Alfa Marine, while the conversion work on the thrusters themselves was carried out at the Schottel service workshop in Spay, Germany.
A cost saving of around 50% was claimed by overhauling the existing thrusters – including the transportation costs to Germany – as opposed to the purchase of new ones.
As a result, the ferry is responding more accurately to steering manoeuvres and the autopilot makes fewer corrections thanks to the much increased course-keeping stability.
Schottel’s hydrodynamic analyses predicted the now realised top speed of 13 knots and various other advantages gained from using the SDV45 nozzle.
In addition to the vessel’s increased course-keeping stability, the new nozzles also ensure the thrusters’ smoother operations. Due to the much-improved thrust and performance on board the ‘Krk’, Jadrolinija is now able to tighten the ferry’s schedule, the company claimed.