Launch of IHC trailing suction hopper dredger Chang Jiang Kou 01. Courtesy Jan van Heteren


Meeting the dredger propulsion challenge


Employing its full range of available tools and experience from sea trials, MARIN is successful in supporting the industry in the complicated field of dredger propulsion.


Finding the sweet spot is definitely a chal- lenge in the design of controllable pitch propellers for today’s dredgers. These working vessels are sailing in deep and shallow waters while travelling to and from the disposal area. As well as free-sailing, these vessels have to perform well while dredging at slow speeds and must provide sufficient thrust to overcome the large draghead resistance without harming the working conditions of their crews. This complex mission profile leads to a rather unique set of design conditions for the ducted propellers of these vessels.


Gert-Jan Zondervan g.j.d.zondervan@marin.nl 20 report


IHC Merwede recently launched a series of two hopper dredgers for Yangtze Estuary Waterway Administration Bureau MOT, based in China. MARIN was involved in the development of the controllable pitch pro- pellers for these vessels by means of model testing. The performance of the ship was predicted and with the help of computa- tional analysis of the ducted propellers,


validated by cavitation experiments in MARIN’s new Depressurised Wave Basin. The propeller design was then finely tuned to meet the requirements of IHC.


Next generation Recently, the perform- ance of the propellers was investigated during sea trials onboard Chang Jiang Kou 01. The high-speed observations using a boroscope provided valuable feedback on the extent of the cavitation on the propeller blades under various operating conditions and the influence of the propeller cavitation onboard the ship. The cavitation experi- ments at model scale concurred and the validity of the current approach using the computational analysis of ducted propellers was confirmed. With this valuable information MARIN is developing the next generation of compu ta- tional tools. Their capabilities will soon be evident when they lead to the further refine- ment of the design of ducted propellers.


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