Cat Unveils New ‘Twin Fin’ Propulsion System

The Cat Twin Fin Propulsion System. Illustration courtesy Caterpillar Marine

Caterpillar Marine is set to formally unveil the new Cat Propulsion Twin Fin System this week at the 2014 ITS Hamburg Conference and Exhibition in Germany.

The Cat Propulsion Twin Fin System is based on a new diesel-electric solution that saves on fuel and emissions, while improving overall vessel performance and ease of maintenance.

What’s interesting about the Twin Fin System is the internal housing of all the propulsion equipment within the hull profile, thus protecting the machinery from harsh operating environments for which the system was initially conceived.

“We developed the Twin Fin system in partnership with Odense Maritime Technology (OMT) and Scandinavian Marine Group (SMG) initially as a solution to make vessels operating in Arctic conditions less vulnerable to damage to the propulsion system,” Mattias Hansson, Caterpillar Marine senior project manager commented. “As the innovative concept has been engineered into vessels, we’ve been pleased to not only see increased reliability but improvements in fuel consumption and thrust performance as well.”

The system itself is comprised of a compact electric motor and gearbox configuration connected via short drive shaft, rotating a pair of controllable pitch propellers with two tailor-made fins attached to the hull. Major transmission parts in the system are all accessible from inside the vessel, enhancing ease of maintenance and averting the need to drydock.

The Twin Fin system is also said to achieve efficiency gains measurable across a range of performance criteria. It offers increased thrust – and requires lower input power – thanks to larger propellers running at low shaft speed plus minimal mechanical loss. Hydrodynamically designed fins ensure homogenous water flow to the propellers for lower fuel consumption plus lower emissions and noise radiation. To fulfill dynamic positioning duties, the Twin Fin System can be specified with tunnel thrusters, either attached to the fins or central skeg running between the fins.

As gCaptain reported previously, Polarcus DMCC was the first operator to incorporate the Twin Fin system on a conversion project involving an Ultstein SX124 vessel. You can see photos of the conversion HERE.

“The Twin Fin system is a tailor-made system developed in close collaboration with our clients and is primarily intended for diesel electric vessel applications. The system is designed depending on the operational requirements and profile in order to achieve optimum performance,” Hansson continued. “In addition to being the most compact system of its kind for offshore vessels, the system has proven to be a robust performer during operation without diminishing maneuverability. It achieves better overall performance and increased cargo loading capacity in comparison with azimuth thruster applications.”