Doen Waterjets - News


February 2016 – The Unmanned Systems Technology magazine published an article on the ECA Group’s Inspector Mk2 Unmanned Surface Vessel (USV) in its 6th issue, Feb/March 2016, which provides invaluable insights into ECA’s choice of Doen waterjets for Mk2.


Building up its USV capabilities since 2008, ECA Group (France) delivered the first Inspector Mk2 USV to an unnamed customer in September 2015. The boat is a shallow draft rigid monohull, designed for endurance of more than 12hours at 10Knots, while having the ability to sprint at 35Knots+, survive in sea state 5 and keep station accurately at speeds between zero to 25Knots.

Inspector Mk2 USV (optionally manned) is designed to form the core platform for an array of modular onboard payloads to suit a wide variety of missions including coastal surveillance, mine countermeasures, rapid environmental assessment,replica watches support for special operations forces and firefighting.

A pair of Doen DJ100G waterjets were chosen to drive this vessel to meet the requirements for high-speed performance, superior maneuverability and excellent cruising fuel economy. The integrated gearbox of DJ100G, eliminates the need for a separate marine gear and allows a perfect match between the waterjet and the 292hp Steyr engine, as well as the other nominated alternative engine options for Inspector Mk2.

The 245mm diameter, high volume axial flow impeller provides great trust across the entire speed range of this USV and exceptional cavitation margin allowing unrestricted full power application that is an essential requirement for towing mine hunting probe at low speeds.

ECA Group required Doen to supply the waterjets with a tailored control interface to suit a third party autonomous control system. Customized DJ100G waterjets were designed for this customer, each waterjet has its own fully integrated hydraulic system providing necessary control input and feedback information required for the third party independent system to control waterjets’ steering and reverse in manned or unmanned (remote or autonomous) mode. The hydraulic pumps are jet mounted and driven off the main shaft.

Doen electronic control systems can also provide for direct CAN BUS interface to third party systems for USV applications. The flexible architecture of Doen’s control interface provides for direct communication of control commands such as bucket and steering as well as engine throttle and gear select. In addition, system status details can be communicated to the remote system for alarm and monitoring purposes.



December 2015 - Two separate Patrol Boats, each fitted with a pair of Doen DJ170HP waterjets were incidentally launched within a week in late December 2015, one in Kaohsiung (Taiwan) and the other in Nha Trang (Vietnam). Both vessels exceeded the contract speed performance expectations.

The Taiwanese vessel, a high-speed aluminium 14m monohull, is designed by eRICH Naval Architect & Yatch Design and built to CR Classification Society rule by Shing Sheng Fa shipyard. Power is provided by twin CAT 746kW diesel engines, which are coupled to the DOEN waterjets through ZF marine transmissions.

This vessel that is now in service by Kaossiung Police has demonstrated excellent performance (46Knots) and has proven to be an extremely cost-effective vessel to build and operate.

The Vietnamese high-speed fiberglass 18m monohull, commissioned by Vietnam Boarder Guard Force (Ministry Of Defence), was built locally and achieved 38Knots during the trial. Power is provided by twin Volvo D13 diesel engines, which are coupled to the DOEN DJ170HP waterjets through ZF325-1 gearbox.

The DJ170HP is a 17” (432mm) single stage compact high performance waterjet that uses Doen’s latest impeller technology to delivers mixed flow type, high speed performance, within an axial build. This approach combines the key benefits of excellent high-speed efficiency with superior cavitation margins and efficiency at lower speeds and cruise conditions. This waterjet model incorporates many innovative features that enhance its application into high-speed craft. The lightweight fabricated intake tunnel for instance enabled DOEN to accommodate the requirement for tailor-made intake design to suit the hull form for this particular vessel.

Steering is by conventional helm using a power assisted hydraulic steering system. An inboard cylinder is directly connected to the waterjets inboard steering tiller. This provides the vessels with exceptional and easy control at all speeds, especially for pursuit and high-speed maneuvers. A simple mechanical tie bar is used to connect the waterjets providing synchronized steering at all times.

The DJ170HP waterjets in both vessels were fitted with DOEN’s Rotary Servo Control (RSC), which is a proportional hydraulic control system providing simple and exact follow up control of the waterjets reverse buckets, by conventional lever. This system has fully integrated hydraulics with in-built cooling; bulkhead mounted reverse cylinders with all hydraulic connections inboard and protected from corrosion. Conventional control levers using push pull cables operate this system.



November 2015, Melbourne, Australia - Doen WaterJets is pleased to add the DJ142 to its current range of waterjet models. Following the successful launch of the best replica watches DJ140HP using the most recent intake and impeller designs, it was timely to introduce this latest 14-inch waterjet model into the market

DJ142 transom mount waterjet perfectly meets DOEN’s key design criteria of high performance, reliability and simplicity of construction and maintenance. This axial flow waterjet delivers compact and efficient performance at speeds up to 45+ knots. Construction comprises Stainless Steel and heavy-duty powder coated Aluminium components protected with an anode anti-corrosion system.

The transom mounting and very low profile of the waterjet ensure minimal intrusion into valuable onboard space. This allows for very low profile swim platforms or additional deck area; and the low propulsion shaft height allows flatter trim for the boat.

The use of modular construction has allowed the DJ142 to be lightweight, compact and simple to maintain and repair while being a robust commercially rated waterjet. The heavy-duty propulsion shaft and bearings, and an upgraded reverse mechanism with two cylinders assist in providing long life and trouble-free operation. The design and construction allow the DJ142 to be easily configured to meet BV, DNV, Lloyds, Rina or other marine standards on customer specification.

Doen’s standard hydraulic rotary servo control (RSC) provides proportional, position sensing, and control of the reversing bucket by way of a 3” (75mm) stroke Morse 33C cable. For twin installations, DJ142 can also be configured with Doen’s fully integrated electronic control system, ECS200.

DJ142 is expected to be in strong demand within the more sophisticated commercial and military markets, typically twin installations in small workboats and patrol vessels up to 15 meter length, powered by inboard diesel engines up to 700hp.

Doen WaterJets is a market leader in design and manufacturing of axial flow waterjets with over 45 years experience in design and application engineering, together with significant investment in R&D and a policy of continuous product improvement placing Doen waterjets at the forefront of the industry.

DJ142 provides yet another testimonial to Doen WaterJets unrivalled capability in offering extremely high-performance waterjets to the marketplace with very competitive pricing.


Press Release - 17th August 2015


Doen Pacific is proud to announce the signing of an exclusive Distributor Agreement for Europe with Sea-Tek (AS) domiciled in Oslo, Norway. In turn, Sea-Tek will appoint agents in several European countries in the near future, selling and servicing waterjets under its umbrella.

Sea-Tek is a key supplier to the marine industry in Europe, who is currently supplying mechanical, electronic, and hydraulic systems for controlling propulsion systems. This specialized market niche enables Sea-Tek to offer turnkey propulsion packages, tailored to customer needs by supplying state of the art engine/waterjet packages fully engineered for installation into the vessel. A ”one stop shop” package supply for any waterjet application in Europe.

Doen Pacific, a leading designer and manufacturer of waterjet propulsion systems for the past 48 years, and is one of only five marine waterjet manufacturers in the world building waterjets to match engines to 4,000kW, with some 4,000plus applications on the water in more than 30 countries.

Stephan Jorgensen, Managing Director of Sea-Tek who has vast waterjet experience, commented that ”Waterjet propulsion offers many advantages over conventional propeller propulsion, such as ’plug & play’ installation, lower engine load factors, excellent safety, as well as the ability to operate in shallow waters without risk of damage. Waterjets are well suited to high speed applications and displacing vessels, with excellent manoeuvrability including an emergency stop system, together with station keeping and Dynamic Positioning features.”

As customer satisfaction and service are important to Sea-Tek, a stock of waterjets and spare parts will be housed in Oslo for availability and immediate delivery to customers throughout Europe. In this way, Sea-Tek will be able to offer complete turnkey maritime solutions simplifying installation, supply, support, service, and reducing delivery times.

”I am very confident this partnership is the right choice for both parties, and we look forward to a fresh face roll out of the Doen Waterjet product throughout Europe” said Doen Director, Mark Peters.



30th March 2015 Korea - Funded by a Korean government R&D program, this prototype vessel is built and commissioned to showcase the credentials of exploiting green technologies in day-to-day domestic marine transport applications; The boat is equipped with hydrogen fuel cells and is driven by electric motors, providing for zero emission operation of this river cruiser whilst also reducing the day to day running costs by 20%.

Power is provided by 25kW H2 fuel cells plus 300A battery bank that drive twin 45kW 3-phase electric motors, which are coupled to the DOEN DJ140HP waterjets through a simple 2.0:1 reduction gearbox. The DOEN 15-inch (380mm) diameter high volume axial flow impellers provide excellent low speed efficiency and cruise capability enabling long range at reduced energy consumption.

The DOEN balanced steering nozzle gives fast and precise response. These are controlled using a conventional manual hydraulic steering system. Inboard cylinders are mechanically connected to the waterjets inboard steering tiller. This provides the vessel with exceptional easy control in both high and low speeds. A simple mechanical tie bar is used to connect the waterjets providing synchronized steering at all times.

The DJ140HP waterjets are fitted with DOEN’s Jogstick Reverse System (JRS); an electro hydraulic control system that provides non-follow up jog lever control of the waterjets reverse buckets. An analogue indicator is used to show the reverse bucket position. This robust, simple and cost effective system remains very popular with operators in remote and rugged use environments. For this particular application, waterjets are supplied with a tailor-made DC powered hydraulic system that allows the JRS to operate when required without placing any continual parasitic load on the electric motors.



10 February 2015, Sydney, Australia - Britton Maritime Systems won the contract to deliver several USVs to the Royal Australian Navy for autonomous mine counter measures (MCM) operations. The USV can be remotely operated, fully autonomously operated without operator intervention or operated as a manned platform. The control system provided by a third party, consists of a command link that provides extensive control features and a comprehensive array of situational awareness data back to the shore or ship based command & control centre.

The custom Mark Ellis aluminium monohull design provides a robust hull to withstand the rigours of operating inside a minefield for prolonged periods. The demanding main propulsion requirement specified a jet and main engine suited for long periods of medium speed multi influence minesweeping and high speed transit, both in USV and manned missions.

To meet the dual requirement of the high thrust for medium speed towing and high-speed performance a pair of Doen DJ120 jets, coupled via ZF transmissions, to Yanmar engines were specified. The 310mm diameter, high volume axial flow impellers provide exceptional cavitation performance allowing unrestricted full power application, for towing, at medium to low vessel speeds. Each DJ120 waterjet has its own fully integrated hydraulic system providing for third party independent control of the waterjet’s steering and reverse control by the unmanned (remote or autonomous) control system. The hydraulic pumps are directly driven from the gearbox PTO’s.

The Doen waterjets are supplied with a tailored control interface to suit the third party autonomous control system. This interface provides necessary control input and feedback information required for the control system to independently operate the waterjets.

Doen electronic control systems can also provide for direct CAN BUS interface to third party systems for USV applications. The flexible architecture of Doen’s control interface provides for direct communication of control commands such as bucket and steering as well as engine throttle and gear select. In addition, system status details can be communicated to the remote system for alarm and monitoring purposes.

USVs can be operated day and night, around the clock conducting a range of persistent missions such as Mine countermeasures with the added advantage of not endangering personnel. They offer significant savings over dedicated MCM vessels and helicopter towed systems.