Wärtsilä Modular Waterjets

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Wärtsilä Modular Waterjets - Jet powered efficiency and reliability

The Wärtsilä WXJ modular waterjets represent the state-of-the-art in this field, delivering outstanding benefits and performance and offering a high-level of customisation with a wide variety of options available depending on the vessel type.

The Wärtsilä WXJ series of modular waterjets features an improved axial pump design, which boosts performance with an increased thrust of as much as 3 percent, while the improved cavitation margins help reduce the environmental impact by lowering noise levels. This axial pump design comes with a 25% reduction in mounting flange diameter, 10% overall weight reduction and a 35% increase in cavitation margin compared to its predecessor, the “LJ type” with a mixed flow pump design, while the small transom interface dimensions, and best in class weight are unchanged.


    The characteristics of a waterjet make it a good propulsor for numerous applications.

    • High speed vessels; waterjets have better propulsion efficiency at ship speeds over 25-30 knots.
    • Shallow draft vessels; the integrated steering function provides benefits for rescue vessels, inshore passenger ferries, landing crafts & special work boats.
    • High power density; the pressure built-up in the waterjet inlet allows small dimensions.
    • Maneuverability; waterjets have integrated steering and reversing with quick response times.

    Examples of such applications include:

    • Fast ferries
    • Littoral combat ships
    • Fast patrol boats
    • Rescue vessels
    • Fast yachts
    • Fast supply vessels and workboats
    • Landing craft

    Key benefits

    Wärtsilä axial waterjets are single stage, compact, high performance systems that combine mixed flow properties with an axial construction. This results in much less space being needed on the vessel’s transom, and greatly increased waterjet cavitation margins for optimum vessel operational flexibility. For naval architects, the axial jet technology creates the possibility to apply a larger power density onto narrower hulls in order to achieve top vessel performance.

    • Lowest size to weight ratio in the market 
    • Axial pump design means less space on the transom 
    • Worldwide availability, including China, Japan, Korea, etc. 
    • Inboard mounted thrust bearing block, for increased life and easy maintenance 
    • Optional inboard hydraulics 
    • High-performance components in Duplex stainless steel to prevent wear and corrosion 
    • Impeller tip clearance guaranteed due to axial shape and no risk of impeller housing collisions. 
    • Customisable to meet your needs 
    • Fully integrated solutions available

    Technical info

    Weight & dimensions table
    Size Outboard
    length SR
    length B
    510 1500 610 2510 655 750 550
    570 1650 650 2790 730 1050 750
    640 1860 730 3040 820 1450 1150
    720 2040 790 3360 920 2050 1450
    810 2310 900 3670 1035  2850 1950
    910 2560 980 4110 1165  4150 2550
    1000 2800 1060 4420 1280  5150 3450
    1100 3040 1130 4770 1405  6700 4300
    1200 3320 1230 5230 1535  8600 5750
    1300 3580 1330 5590 1665  10950 7100
    1400 3870 1450 5940 1790  13150 8200
    1500 4120 1520 6430 1920  15900 10100
    1620 4470 1650 6860 2075  20400 12650
    1720 4770 1780 7270 2200  21500 15300
    1880 5200 1930 7840 2405  31450 18900
    2020 5550 2140 8320 2585  36150 23400
    2180 6000 2300 8880 2790  43900 29100
    2350 6440 2470 9460 3005  53000 34000
    Inboard length may vary depending on the optimized shape of the inlet duct
    Modular WJ Technical info

    Downloads & links

    Wärtsilä waterjets speed up the world’s fastest vessels
    14 Mar 2019 · Article
    6 min read
    Wärtsilä waterjets speed up the world’s fastest vessels
    Waterjets have many exciting applications from navy vessels to big, fast ferries, as...
    Wärtsilä waterjets speed towards new innovations
    7 Mar 2019 · Article
    4 min read
    Wärtsilä waterjets speed towards new innovations
    They help power some of the world’s biggest and fastest vessels. Find out why Wärtsilä’s waterjets...

    We are committed to creating innovative solutions and further developing existing products in order to serve our customers even better. The new Wärtsilä WXJ modular waterjets represent the state-of-the-art in this field, delivering outstanding benefits and performance.

    Sander van Oosterhout, Product Director Waterjets, Wärtsilä

    Waterjet size selection

    The selection graphs indicate the jet size required based on the relation between the engine power and the design speed of the vessel. For instance a ship with four 1250 kW engines and a corresponding vessel speed of 33 knots will need four 510 size waterjets. A ship with a design speed of 40 knots at 1250 kW power can use 450 size waterjets. The correct jet size is thus indicated by the line above the intersection of the power and the corresponding vessel speed (see examples in the graphs below).

    We are available from the earliest design stages of the vessel to work with you on an optimised propulsion system. Please contact us  for  an  optimised  jet  selection  based  on  specific  vessel  design parameters, operating profile or for details of waterjets above 50 knots or 30 000 kW. DXF/DWG format general arrangement drawings of the most often used sizes are available.

    Additional design information can be found in the “Waterjets Product guide”, which can be pre-ordered on this page.


    Customer stories

    Sailing with fast vessels is a bit like Formula 1 racing. The lighter you are, the better the performance. Therefore, we are always looking into new solutions to save weight and to improve the performance even more.

    David van Luijtelaar, Global Sales Manager Waterjets, Wärtsilä

    Waterjets Team

    Sander van Oosterhout

    Sander van Oosterhout
    Product Director Waterjets

    David van Luijtelaar

    David van Luijtelaar
    Global Sales Manager Waterjets

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