Two Engines, One Propeller
A recently launched patrol vessel, Zhong Guo Yu Zheng, for the Chinese Fisheries Department employs the proven technology of two engines turning into a gear with a single output to a single propeller.
The Fisheries Administration Ship is 57.33-meters overall with a 8.2-meter beam and a depth of 4.2 meters. Design draft is 3.2 meters. A pair of Cummins (CMI) QSK60 main engines, each delivering 2000 HP at 1800 RPM, provides propulsion power for the 500 DWT-vessel. The two engines turn in to a massive marine gear from Hangzhou Advance Masson Marine Transmission Ltd. The gearbox combines the total of 4000 HP from the two engines. After reducing the RPM by a 7.5397:1-ratio, the power is delivered to a single shaft. Mounted on the shaft is a single 2.85-meter controllable pitch propeller. The arrangement gives the vessel speeds up to 18-knots.
A pair of 200 kW generators, powered by Cummins 855 engines, meets the ship’s electrical requirements. Accommodation is provided for up to 30 people. For boardings and fast patrols the ship carries two FRP speedboats, each powered by a single 200 HP outboard on the stern deck. The vessel was built over a 12-month period at the Rushan City Ship Building Company Ltd. in Northern China’s Shandong Province. (http://en.rszc.com ) Also building at the yard in early December 2011 were several ships including a 6500-DWT chemical tanker as well as a pair of massive pile drivers, one with a 95-meter mast and the other with an 86-meter mast.