HJ Designer Guide
16Pages

DESIGNER’S Manual

General Description • Performance Calculations • Propulsive Efficiency • Engine & Gearbox Selection • HJ Series Dimensions • Scope of Supply • Installation Guidelines • Driveline Requirements • Control Systems • Material Specifications • The HamiltonJet Total Waterjet Solutions With experience spanning six decades, HamiltonJet provides a totally integrated waterjet propulsion solution to the marine industry. From initial enquiry through the lifespan of a vessel, HamiltonJet offers a comprehensive customer support package that is second to none. We want your waterjet vessel to be the most...

HJ Series General Description HJ Series General Description STEERING TILLER DRIVESHAFT \ TRANSOM SEAL HamiltonJet waterjets are an advanced marine propulsion system suitable for a wide variety of high and low speed applications. The waterjet utilises a highly developed water pump to generate a high velocity jet of water which, when expelled out the stern of a vessel, generates a thrust force in the opposite direction to push the vessel forward. The waterjet mounts inboard at the stern, drawing water through an intake fixed to the hull bottom. The intake is protected by a screen which, at...

Performance of any marine vessel depends on several key factors and how they affect each other. These factors include... • Hull resistance • Engine power at different rpm levels • Size and number of propulsors At HamiltonJet we can accurately predict vessel performance using specialist computer software, provided the information we receive from the designer, builder and engine supplier is accurate to the finished vessel. For any new vessel built to be propelled by HamiltonJet waterjets, we will provide a detailed performance prediction to assist with waterjet sizing, engine & gearbox...

HJ Series Performance Calculations Power Required Per Waterjet Understanding the Risk of Over Loading Knowing the speed required at maximum displacement of your vessel, use the diagram below to calculate the approximate Power to Weight Ratio required for the speed and length of the vessel. Waterjet propulsion is more sensitive to weight changes in a vessel than other forms of propulsion. In many cases this can be a major advantage in speed and efficiency, however if the weight is significantly increased it can result in poor speed performance, inability to get on the plane and unsuitability...

Making the Most Efficient Selection By using the calculations from the previous pages you will have determined likely waterjet size options for your vessel, and from this have an idea of the engine power you will require. Now you can look more closely at propulsive efficiency to further narrow down your waterjet selection options. In general, propulsive efficiency is affected by the size of the propulsor - larger is more efficient with the same engine power input. However, it is important to consider other design factors of any propulsion system which can directly affect its efficiency at...

HamiltonJet Engine / Gearbox Selection Thrust Required per Waterjet = Bare Hull Resistance (no appendages) Number of Waterjets In the case of our example boat, HamiltonJet’s hull resistance software calculates that a laden weight of 12,000kg requires 23kN (4,700lbsf) of thrust to achieve a speed of 35 knots - which fits with the single HJ403 option. For twin waterjets this translates to 11.5kN (2,355lbsf) per jet, which is borderline for the HJ292 option but fits well in the HJ322 optimum efficiency thrust curve envelopes. To narrow down waterjet selection options further you can look at...

NOTES: a - HJ212 "A" dimension is to the end of a splined shaft. May be close coupled. Layout and dimensions shown are indicative only for initial design purposes, based on jets with standard 5° intake block which facilitates close direct drive coupling of the engine. Consult HamiltonJet for more detailed information.

optional 0o intake block (Available with selected HJ waterjets only) NOTES: Layout and dimensions shown are indicative only for initial design purposes, based on jets with optional 0° intake block which positions the jet parallel to the hull bottom. Consult HamiltonJet for more detailed information.

HJ Series Scope of Supply Standard Supply (All Waterjet Models) • Waterjet Base Unit ("Wet-Run") • Intake Block with Screen & Installation Kit (to suit aluminium, GRP, wood or steel hulls) • T ransom Seal Kit • Coupling Flange (to suit specified driveline) • Impeller to suit engine Power/RPM & Gearbox (if fitted) • JHPU - Jet Mounted Hydraulic Power Unit (excluding HJ212) • Astern Deflector • Hydraulic Reverse Cylinder (excluding HJ212) • Reverse Control Actuation Assembly (for HSRX, HSRC or HFRC- see page 10) • Steering Assembly (JT Steering Nozzle, Shaft and Steering Tiller) • Complete...

rerse Deflector ontrol Lever Helm Pump & Wheel Additional Extras (Required to Complete Installation) • Cable or Hydraulic Steering Kit (HJ212 - HJ274 only) • Helm Wheel • Engine Throttle Control Levers • Ahead/Astern Control Lever/s • Tie Rod Kit (HJ213 - HJ274 multi-jet installations) NOTE: Additional extras can be supplied by HamiltonJet if required Tie Rod (connects steering tillers in multi-jet installations) additional Extras (Not Necessarily Essential to Complete Installation) • Intake Screen Rake • Inspection Hatch Extension • Sand Trap • Special Tools Kit • Certification (ABS,...

HJ Series Installation This section briefly explains how the jet is mounted in the hull. Detailed installation drawings are available on request and are also included in the Product Manual which comes with the jet. With the astern deflector assembly removed, the jet can be assembled from inside the hull (HJ212-HJ322) or from outside the hull (HJ364-HJ403) onto the intake block. Intake bolted to intake block with blind studs. Intake block – fibreglassed into GRP or wooden hull, welded into metal hull. Transom seal plate through bolted Intake Block Typical Jet Installation (Aluminium Hull...