Willy Vranken, owner of Scheepvaartbedrijf VrankenBV based in Maasbracht, Netherlands, has put a lot of thoughts into a propulsion system for his new inland waterway ship, which ensures the maximum benefit for him. At Boost-Shipyard, Trier / Germany, the hull was built: “I want to have a ship which is of high quality. The imported hulls do not fulfill my requirements”. The complete interior has been done by Dutch company Koedood Dieselservice. The bulker, named GOBLIN, features 135 m in length, 11.45 m in width and a max draft of 3.79 m. With this the ship can load 4.400 to.
The hybrid propulsion
Willy Vranken has decided to go for a two propeller ship. “With this, I have the possibility to navigate also in low water periods, because both the propellers have a smaller diameter”. The drive line consist, for each shaft, of a 12 cyl Mitsubishi Diesel Engine of type S12A2-PTA with a max output of 634 kW at 1.940 rpm via a Masson Marine reversible reduction gear unit with a ratio of 1:5,913. On each shaft, between gear box and propeller, one Baumüller water cooled torque electric motor of type DST2 has been installed. These electric motors create a power of 285 kW with a torque of 9.100 Nm each. With this the propeller speed is of 230 rpm. A separate genset – featuring also a Mitsubishi 12 cyl Diesel Engine of type S12A2-PTA, adjusted at 634 kW at 1.800 rpm supplies via a Stamford Generator, type HCM 634 K2, 815 kVA mainly for the two torque motors. At low load requirement this genset can run also at 1.350 rpm. Consequently the noise emission is drastically reduced. All three Diesel Engines feature a SCR catalyst of company Emigreen BV, Netherlands. If later on necessary, a particulate trap system can be installed in the exhaust line.
With this propulsion configuration the ship’s officers have, according to load and water conditions, variable propulsion possibilities:
1. Pure diesel mechanical: diesel engine – gear - propeller. Propeller hereby is of 328 rpm (the torque motor runs on idle, but can be used as a generator)
2. Diesel mechanically and electrically torque motor. With this the total output of the two systems is 919 kW ending in a propeller speed of 347 rpm.
3. Pure diesel electrically: genset – torque motor with a propeller speed of 230 rpm.
The different propulsion systems are controlled via a Baumüller PLC (programmable logic controller). This PLC contains multiple control and monitoring functions.
Exhaust Aftertreatment System
Willy Vranken decided to choose diesel engines according to Step 0 of the EU-RL 97/68/EC, but with an additonal SCR system for each engine. With this the actual European Exhaust Limit Values are fulfilled. The additional required AdBlue (for the SCR systems) consumption is around 5% of the diesel fuel consumption.
In different publications it is mentioned that “with beginning of 2016 a CCNR 4 regulation” will come in force! But this is not true: According to the EU commission for emission regulations the current exhaust limitations are under a process of revision and this includes also possible more stringent limit values. But due to the long lasting internal discussions of the commission it will not be announced before 2018.