INTRODUCTION TO JET DRIVES

About Jet Drives

The Jet Drive is Simple.  A jet drive is a water pump, which is driven by a automotive engine that has been specially prepared for marine use.  The engine is mounted within the hull and connected directly to the pump.  There is no clutch or gear box.

The jet receives water through an intake grate in the bottom of the boat, and ejects the flow beyond the transom and through a steerable nozzle.  The pump impeller, in ejecting the water, creates an equal force in the opposite direction which propels the boat forward.  Steering is done by swinging the nozzle and rudder right or left, as desired.

The boat's attitude can be controlled by pointing the nozzle up or down within a controlled range on models with underway trim.

Reverse is accomplished by lowering a reverse gate across the outflow, diverting the jet stream forward, beneath the hull.  Lowering a reverse gate when the boat is going forward, can stop the boat virtually within its own length.  (Stopping should be done carefully to prevent passengers or free objects from being tossed forward.)  There is no extra strain on the engine or the Jet Drive when going from forward to reverse.  The drive system can't detect the change;  its rotation and load are not affected.

The jet drive does not know how heavy your boat is, or what speed the boat runs.  Simply, the Berkeley jet drive in your boat is matched to the engine and will deliver about 1400-1800 pounds of thrust while pumping 3000 to 4000 gallons of water every minute at a pressure of 60 to 180 pounds per square inch (PSI).