Singapore-based Sembcorp Marine is to use Schottel’s azimuthal hybrid drive system for what is claimed to be the world’s first liquefied natural gas (LNG) hybrid tug. The vessel, the first in a series of 12 that will replace Sembcorp’s existing diesel-powered tugs, is designed by LMG Marin, a wholly owned Sembcorp Marine subsidiary.
Sembcorp notes that the tug’s future operation profile in the harbors of Singapore will demand highly variable power ranges. Depending on the desired operating mode and the required propulsion power, the hybrid drive system will activate the appropriate power source, or both together. The LNG-fueled main engines and the electrical motors are both coupled to the Schottel system and are designed to always operate within their optimal load ranges, thereby reducing fuel consumption and emissions.
In terms of thruster integration, each Schottel upper gearbox offers two power input positions with an offset angle of +/-90° for two power sources. An option with a +/-135° offset angle is also available allowing even more design flexibility. The Schottel SRP 430 Rudder Propellers have a power intake capacity of about 2,000kW each which will be fed by zero-emissions electrical motors and/or the low-emissions LNG main engines.