Case Study: Bow Thrusters and Fluid Pumps on LNG Carriers

Transportation of liquefied natural gas (LNG) between North Africa and the USA is a thriving and lucrative business for carrier companies, and AuCom soft starters helped one shipping firm to overcome a common problem and reduce operating costs, while maintaining rigorous safety standards.

Two Algerian registered gas carriers, the Bachir Chihani and Larbi Ben M’Hidi, regularly ply the trans-Atlantic route. Both vessels were equipped with bow thrusters to improve maneuverability during berthing, but increasing demand on the on-board electric generators meant they could no longer start the bow thrusters. This meant that the vessels had to use expensive local tug services to enter port.

AuCom replaced the existing star/delta starters with 1600 kW soft starters, which control the starting current of the bow thrusters and keep them within the limits of the generator.  Soft starters benefit systems with limited electrical capacity by:

• Limiting start current to the minimum level required to successfully start the motor. This lets larger loads be started on the same supply.
• Slowing the application of starting load, giving the generator set more time to respond.
• Reducing electrical disturbance which can be caused by star/delta starters when the starter switches between modes. Soft starters reduce the disruption to other equipment running on the same supply.