China's development of heavy-duty machinery has earned so much pride for the country in recent years. The self-propelled cutter-suction dredger, Tianjing or Sky Whale, is one good example.
The vessel is the largest cutter-suction dredger in Asia. Financed by Tianjin Waterway Bureau Limited under China Communications Construction Company Ltd (CCCC), the dredger is co-designed by Shanghai Jiaotong University and German company, VOSTALMG. It was built by China Merchants Heavy Industry (Shenzhen) Company Ltd.
Surrounded by steel frames and crane arms, the vessel's deck is more like a construction site. The only thing that distinguishes it from a real construction site is its clean environment. People on the vessel are required to put on safety helmets once they step out of the cabin.
China has a long history of dredging, though modern technology has since replaced human labor.
Tianjing has been hailed as a mighty tool for island-building because of its strong excavation and hydraulic reclamation ability. According to a crew member, Tianjing can excavate 4,500 cubic meters of mixture from the seabed each hour - the equivalence of a 0.5-meter-deep pit and a standard soccer field size.
Cuts rocks as easy as mud!
The vessel's reamer has endowed it with powerful ability. The reamer is normally inconspicuous in pictures, but people will be astonished when standing right in front of it. The diameter of small reamers is 2.8 meters, while that of larger ones could reach 3.15 meters, said Wang Ming'an, former Tianjing captain and vice general manager of the Overseas Business Division of the CCCC Tianjin Waterway Bureau Limited.
It was learned that the unit price of the cutter tooth on the reamer, which is used for excavation, is 1,500 RMB ($223). Driven by a 4,200-kilowatt variable-frequency motor, the cutter teeth could excavate moderately- and highly-weathered rocks with compression strength as high as 40 MPa.
"Concretes can be easily ground by the reamer," said Wang, adding that rocks are as soft as mud for the machine.
Powerful self-propelling ability, automatic dredging control system
In addition, the dredger has two other "killer skills": powerful self-propelling ability and advanced automatic dredging control system. The cockpit located on the top floor of the vessel is the "brain" that realizes the two functions.
Covering an area of about 40 or 50 square-meters, the cockpit offers a strong taste of high-tech style that can easily be associated with the flight deck of a spaceship in a sci-fi movie.
The automatic dredging control system lies in the cockpit, integrating all operations in a 2-square meter station. The remote control is operated just by clicking the mouse or pushing the buttons. Crew members can even take a cup of tea while excavating, a staff on the vessel explained.
Positioning and self-propelling systems are on the two sides of the dredging control station. The staff member said that cutter-suction dredgers are not new as they have been widely applied in engineering dredging projects.
However, most of them are not equipped with self-propelling systems. They depend on other ships to mobilize to different work points. As Asia's first self-propelled cutter-suction dredger, Tianjing can sail to any part of the ocean.