Videos – How It Works

In an age where riding lawnmowers have long enjoyed more than one gear, and efficient home appliances are electronically controlled, boats are still propelled by simple, single-speed propellers and water jets.

Imagine how your car would work, if it couldn’t shift gears. Even a Model T Ford had two forward gears, but propeller and jet boats only have one, which gives them a limited range of efficient operation in terms of load and speed.


Jet aircraft, like the ME262 on the  right started out with a simple jet, but by the 1960s the SR-71 shown below incorporated controllable inlets, multiple controllable boost stages, and a controllable nozzle, which allowed it to operate efficiently over a very wide range of speeds.


sr-71-Variable Inlet, Turbine, Nozzle

IntelliJet similarly incorporates a controllable inlet, controllable-pitch pump, and controllable nozzle to operate efficiently over a wide range of speeds and loads. The ideal boat would change the size of its propeller or jet under computer control, as boat speed and load changed for better performance and fuel efficiency.


IntelliJet naturally has a large jet at low speeds and reduces the jet size with increasing boat speed, as part of its CVT automatic transmission function for the motor. This results in a much higher conversion of power to thrust, which reduces the power demand on the motor and further reduces fuel consumption.

Below is a comparison of the IntelliJet test boat with the original sterndrive on the left and the IntelliJet prototype on the right.


Swimmer under Propeller

The under-water views  are shown above. Like most marine jets, IntelliJet is much less likely to injure people in the water or to damage marine mammals, seagrass, coral, and other marine life. At the same time, it is less likely to damage itself on submerged rocks, logs, and other hazards, which makes it more reliable.

Here is a quick look at the prototype pump demonstrating its forward, neutral and reverse pitches.  Note that it always rotates in the same direction for the full range of forward and reverse. At low speeds, the changing pitch provides a smooth range of thrust from full forward to full reverse for excellent maneuverability. At higher speeds, the forward pitch is adjusted by an electronic controller to manage the power demand on the motor like a CVT automatic transmission.

Using electronic controllers similar to that used in cars and trucks, the total system of motor and IntelliJet produces many advantages, including:

  • Higher performance
  • Higher fuel efficiency
  • Both high-speed and heavy-load capable
  • Maneuverable at all speeds
  • High reliability and maintainability
  • Safe operations
  • Shallow draft capability
  • No rooster tail

The electronic controller achieves these results by

  • Operating the motor efficiently by adjusting the pump pitch
  • Maintaining pump efficiency by adjusting the nozzle
  • Maintain inlet efficiency by adjusting the inlet slide
  • Minimize jet velocity for maximum conversion of power to thrust

The following video shows the location of the system components in the boat, including the inlet, the pump, and the nozzle. (This inlet slide action is also used to maintain inlet efficiency at higher boat speeds.)

This next video shows the bottom half of the pump housing removed to show the action of the pump pitch in combination with the inlet slide and nozzle to provide continuously variable forward, neutral, and reverse thrust.

This next  video swings around to the rear view to show the steering action of the nozzle, the power trim function, and the closing of the nozzle as it would at higher boat speeds to maintain pump efficiency.

Here is an 18-second video demonstrating the low-speed turning capability of the prototype in the test boat.

The system operates the motor efficiently by varying the pitch on the pump to create a continuously variable transmission (CVT), like the CVTs used in automobiles. This function is also used to generate variable thrust from full forward through neutral to full reverse for maneuvering at lower speeds.

IntelliJet is based on a modular design that allows the major components to be quickly removed and replaced. Here is a quick video on the removal of the nozzle and pump modules.

These advantages make the IntelliJet boat the safest, most fuel efficient, most cost-effective and most sustainable option.

All content on this site copyrighted by IntelliJet Marine, Inc. 2000-2016