Recently, the domestically‑developed largest controllable‑pitch rudder‑propulsion system by Suzhou Cosc Marine Machinery has successfully passed the new‑product appraisal organized by the Jiangsu Economic and Information Technology Commission. Experts on the appraisal committee unanimously agreed that all technical indicators and structural design of the product have reached a relatively high level both domestically and internationally.

The NRP550 controllable‑pitch rudder‑propulsion system independently developed by Suzhou Cosc Marine Machinery features a rated power of 4 000 kW, a propeller diameter of 3 500 mm and a maximum input torque of 52 525 N·m. It is currently the rudder‑propulsion system with the highest power and largest propeller diameter in China. Its adjustable‑pitch propeller blades enable the main engine to drive shaft generators or fire‑fighting pumps under constant‑speed mode. This improves the comprehensive utilization rate of the main engine, reduces overall vessel energy consumption and construction costs, saves on‑board space and enhances vessel manoeuvrability.

This product from Suzhou Cosc Marine Machinery adopts skewed propellers and high‑efficiency nozzles. Cavitation verification for propeller blades has been performed to mitigate cavitation impact and extend blade service life. Spiral bevel gears adopt the Klingelnberg tooth system for higher load‑bearing capacity and smoother power transmission. Equipped with a novel built‑in disc‑type pitch‑feedback mechanism and advanced hydraulic system, the controllable‑pitch rudder‑propeller delivers advantages including stable system performance, low energy consumption, and high precision in pitch adjustment and rudder steering.

Integrating propulsion, steering and pitch‑adjustment functions, the product enables special manoeuvres such as vessel turning on the spot, transverse movement, rapid astern running and low‑speed steering. Furthermore, on‑board shaft generators or fire‑fighting pumps can be directly connected to the propulsion main engine, eliminating the need for an additional dedicated main engine for such equipment.

The product is widely applied in special‑purpose vessels and offshore engineering sectors, including tugs, pusher boats, floating crane vessels, semi‑submersible offshore platforms, wind‑farm service vessels, semi‑submersible transport vessels, dredgers, ferries and work barges.

Up to now, Suzhou Cosc Marine Machinery’s NRP rudder‑propeller series has obtained 23 patents, among which 5 are invention patents. Over 200 units have been ordered, and more than 80 new‑unit orders are expected to be added this year.