Viking Line Takes the Tension Out of Harbor Mooring for M/S Gabriella

Around one million passengers a year travel between Helsinki and Stockholm on Viking Line’s cruise ferries each year. With affordable tickets and duty-free goods, it’s no wonder that Northern Europeans are taking to the sea. But few passengers realize just what it takes to give them a memorable, seamless cruise experience from the moment they embark the ferry to arrival at their destination. And playing a key role behind the scenes are winch mooring systems equipped with ABB technology.    

Viking Line is one of Finland’s largest shipping companies. With seven vessels, including the M/S Gabriella, the company offers passenger travel and cargo carrier services on routes connecting Finland, Sweden and Estonia. The Gabriella is one of the two ferries sailing between Sweden and Finland, travelling the Helsinki-Stockholm route every other day of the week. The cruise ferry takes about 2,400 passengers and a crew of 170, and can load about 300 cars or 900 meters of semi-trailer trucks. A year ago the 25 year old vessel underwent a major renovation and upgrade project before returning to its voyages across the Baltic Sea. To ensure the best possible cruise experience for the passengers, Gabriella’s cabins and entertainment areas such as spa premises, restaurants and duty-free area were upgraded. In addition, some of its deck equipment was also upgraded, including the mooring winch systems. As a long-standing ABB customer, Viking Line turned to ABB once again to implement a state-of-the-art mooring winch solution comprising latest motor and variable frequency drive (VFD) technology.

Smooth cruising from the beginning to the end

Mooring is one of the essential aspects of the cruise that is often overlooked. It needs to be as safe and smooth as possible regardless of how harsh the weather conditions, how high the waves and how much the draft changes at harbor. An automooring system is crucial for a cruise ferry like the Gabriella since its draft in the water can vary considerably as hundreds of vehicles and thousands of passengers board and disembark. So constant, precise adjustment to the mooring winches is vital to maintain the correct tension in the ropes. Following the hand-mooring procedure, and with the rope already pre-tensioned, automooring can be enabled. This is a speed control application with torque limitation for smooth stepless mooring.

Automation enables easy, smooth mooring

ABB’s solution, a synchronous reluctance motor (SynRM) and ACS880 variable frequency drive package introduces a new winch concept, which is based on ABB’s direct torque control (DTC) platform. The new winch concept enables precise motor control and operation while eliminating the need for costly and troublesome encoders, load cells or external controllers. The simplicity helps improve reliability and reduces maintenance needs. But most important for the ship’s crew is that the functionality built into the winch drive makes the mooring system easy to use. Boatswain Satu Pankinaho says that the instant response with much faster start and stop times now provided by the SynRM motor-drive package has had a positive impact on crew operations, since the operator simply has to release the mechanical brake and let the speed controller take over. “If you start the winch and you need to change the speed between settings one, two and three, it's very smooth. That's what we all like.” The software in the drive uses the torque information from the motor together with its algorithms to determine how the rope tension has changed. The system then makes the automatic adjustments needed to bring the tension back to the setpoint selected by the operator. When the correct setpoint is reached the motor goes back to sleep and the sequence continues until the Gabriella is ready to leave harbor.

Reliable operation for safe mooring

Operational reliability is absolutely essential when operating a mooring winch. "It has to be reliable. That's the most important thing. You must know that you can rely on it every time." Smooth operation is not only for the comfort of passengers boarding and disembarking the ferry, though. Personnel safety is also guaranteed with the control technology that crew trusts in. “It’s a matter of our security that everything is working like it should,” Satu concludes.