Each ferry will have a single controllable pitch propeller driven mechanically by two Wärtsilä engines while an azimuthing pod drive immediately aft of the main propeller will be electrically driven from two Wärtsilä engined gensets. The pod drive will be in contrarotation to the main propeller, providing Contra-Rotating<$>Propeller (CRP) pod propulsion.

The 224.5m LOA ferries are designed for a trial speed of 31.5 knots. The twin Wärtsilä 12V46C main engines used for mechanical drive of the main propeller have<$>a combined output of 25.2 MW. The electrical power for the 17.6 MW azimuthing pod drive and the hotel load is supplied for each ferry by two similar Wärtsilä 12V46C engines as main gensets and one smaller harbour genset.The CRP pod installation results in lower power demand than a conventional twin shaft arrangement owing to the lower resistance of a single skeg hull form and improved propulsion efficiency. The aft propeller takes advantage of the rotative energy left in the<$>slipstream of the forward propeller when it turns in the opposite direction. The single skeg hull also leads to a favourable wake field for the propellers.

The new CODED machinery with a CRP pod offers most of the benefits associated with both diesel-electric and dieselmechanical machinery without their respective drawbacks. The result is a competitive solution providing good technical and economical performance for fast RoPax vessels.

MJ Information No: 18346