W?rtsil? Modular Waterjets

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
    • Best performance in the market based on more than 35 years of waterjet experience
    • 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

    Technical info

    Weight & dimensions table
    Size Outboard
    length SR
    length B
    510 1500 610 2290 655 750 525
    570 1650 650 2600 730 1050 700
    640 1860 730 2870 820 1450 1100
    720 2040 780 3210 920 2000 1400
    810 2320 900 3550 1035   2800 1900
    910 2560 960 4020 1165   4000 2500
    1000 2800 1050 4360 1280  5000 3400
    1100 3040 1120 4740 1405  6700 4300
    1200 3310 1220 5260 1535  8600 5750
    1300 3580 1320 5640 1665  11000 7000
    1400 3870 1440 6020 1790  12500  8100
    1500 4110 1510 6520 1920  15300  10200
    1620 4470 1640 6970 2075  18900  12600
    1720 4770 1780 7410 2200  23200 15100
    1880 5190 1920 8030 2405  29200 19100
    2020 5580 2050 8550 2585  34300 23500
    2180 6020 2210 9160 2790  42500 28100
    2350 6450 2380 9800 3005  52500 34400
    Inboard length may vary depending on the optimized shape of the inlet duct
    Waterjet IBL_OBL
    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, Wärtsilä’s Product Director Waterjets

    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.

    Marine Solutions 160-2
    Marine Solutions 160-1
    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.
    Jeroen Vedder, Sales Manager, Wärtsilä Waterjets




    Hales Trophy
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    The Hales Trophy for the fastest Atlantic crossing by a commercial passenger vessel
    Express 4
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    The world’s fastest high speed ferry to utilize liquefied natural gas (LNG) as fuel
    Saint John Paul II
    The largest high speed catamaran operating in the Mediterranean Sea
    Baleària LNG-fuelled
    The largest LNG-fuelled high-speed catamaran
    USS Independence
    Innovative combat ship
    USNS Spearhead
    Joint High Speed Vessel
    SAS Amatola
    South African Navy’s major surface ships

    Press releases


    W?rtsil? waterjets speed up the world's...

    Waterjets have many exciting applications from navy vessels to big, fast ferries, as W?rtsil? has been...
    14 March 2019
    • Twentyfour7. article

    W?rtsil? waterjets speed towards new...

    They help power some of the world’s biggest and fastest vessels. Find out why W?rtsil?’s waterjets have...
    7 March 2019
    • Twentyfour7. article

    W?rtsil? keeps Incat in the fast lane

    For 30 years, W?rtsil?'s waterjets have played a vital role in helping Incat build some of the world's...
    28 February 2018
    • Twentyfour7. article

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