Marine Ducted Propeller


About product

A ducted propeller, also known as a Kort nozzle, consists of a circular duct with an airfoil section installed on the outer edge of a conventional propeller. The duct can be either fixed or rotating, with the rotating duct acting as a rudder blade. The purpose of the duct is to improve propeller propulsion efficiency by creating additional thrust and reducing flow losses.

  • Improved propulsion efficiency through pressure difference and reduced flow losses.
  • Enhanced maneuverability and control in confined spaces.
  • Reduction of wake contraction for increased energy efficiency.
  • Suitable for tugboats, pusher vessels, workboats, and offshore support vessels.

Additional information


pushing power

Product Detail

Inside the duct, the flow velocity is higher and the pressure is lower compared to the surrounding water. This pressure difference generates an extra thrust on the duct walls, contributing to improved propulsion efficiency. The clearance between the duct and the propeller blade is minimal, which helps minimize flow losses around the blade tips.

Additionally, the duct helps reduce wake contraction behind the propeller, resulting in reduced energy losses. This design feature enhances the overall efficiency of the propulsion system. However, it’s important to note that the reversing performance of a ducted propeller is typically poorer compared to conventional propellers.

The use of a fixed ducted propeller can increase the rotating diameter of the ship, which may impact maneuverability and require adjustments in vessel design. On the other hand, a rotating ducted propeller can improve the rotating performance of the ship, enhancing maneuverability in confined spaces.

The Using Environment Of Ducted Propeller

  • Tugboats and Pusher Vessels: Ducted propellers are well-suited for tugboats and pusher vessels that require enhanced maneuverability and bollard pull capabilities. They provide increased thrust efficiency and better control during towing and pushing operations.
  • Workboats and Offshore Support Vessels: Workboats and offshore support vessels often operate in restricted and challenging environments, such as oil rigs or offshore construction sites. Ducted propellers offer improved maneuverability, astern thrust performance, and protection against potential damage from floating debris or grounding.
  • Ferries and Passenger Vessels: Ducted propellers can be found in ferries and passenger vessels, particularly those operating in shallow waters or congested harbors. The enhanced maneuverability and reduced wake turbulence contribute to a smoother and more efficient operation, enhancing passenger comfort.
  • Research Vessels and Survey Ships: Ducted propellers are commonly used in research vessels and survey ships that require precise control, reduced noise, and vibration levels. The improved efficiency and maneuverability of ducted propellers make them suitable for conducting scientific experiments or hydrographic surveys.
  • Fishing Vessels: Ducted propellers can be beneficial for fishing vessels, especially those engaged in trawling or net hauling operations. The increased thrust efficiency and maneuverability assist in precise maneuvering of the vessel during fishing activities.
Know Who We Are

About our company

Zava Marine Corporation is a leading supplier of marine parts and components. With a strong focus on quality and customer satisfaction, we specialize in providing a comprehensive range of high-quality marine equipment and accessories. Our products include deck equipment, ship accessories, and various other essential components needed for smooth maritime operations.

With a global presence, we serve a diverse customer base, including shipbuilders, shipowners, offshore operators, and marine equipment distributors. We are committed to providing exceptional service and tailored solutions to meet our customers’ unique needs.


Zava Marine offers a comprehensive range of certifications for marine parts in accordance with international standards and regulations. These certifications include those provided by renowned marine classification societies such as Lloyd’s Register (LR), Bureau Veritas (BV), China Classification Society (CCS), Registro Italiano Navale (RINA), American Bureau of Shipping (ABS), Nippon Kaiji Kyokai (NK), and Det Norske Veritas – Germanischer Lloyd (DNV-GL). By collaborating with these esteemed societies, Zava Marine ensures that our certified marine parts meet the highest standards of safety, quality, and performance, instilling confidence in our reliability and compliance within the maritime industry.

The warranty provided by Zava Marine covers defects in materials and workmanship for a period of two years from the date of purchase. During this warranty period, if any marine parts purchased from Zava Marine exhibit issues or failures resulting from manufacturing defects or faulty materials, Zava Marine will take responsibility for repair or replacement of the affected parts. 

Zava Marine has recently opened new molds for European and North American clients, utilizing materials such as metal, ABS, PVC, and more. These successful mold opening projects allow us to provide customized marine parts and components that meet the specific requirements of our clients in these regions.

Typically, Zava Marine can ship samples within 7 days once the product drawing has been mutually confirmed by both parties. This efficient process ensures that customers can receive samples promptly, allowing them to assess the quality and suitability of the products.

Zava Marine frequently utilizes a wide range of materials in our projects. These materials include aluminum, stainless steel, carbon steel, copper, plastics, titanium, and PEEK (Polyether Ether Ketone). Each material offers unique properties and characteristics suitable for various marine applications. 

Yes, we provide customization services for marine parts. We understand that every project and application may have unique requirements, and we are committed to delivering tailored solutions. By collaborating closely with our clients, we can adapt our products to specific specifications, ensuring optimal fit, performance, and compatibility. Whether it’s modifying existing designs or creating entirely new parts, our customization services cater to the diverse needs of the maritime industry.

Absolutely! We offer product design and development services to support our clients’ needs. Our experienced team of engineers and designers can collaborate with clients from concept development to final product realization. By leveraging our expertise in marine engineering and design, we can provide valuable insights and innovative solutions. Whether it’s optimizing existing designs or creating entirely new products, we are equipped to assist clients in bringing their ideas to life efficiently and effectively.

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