How HP Turns To Thrust On The Water

We’ve done plenty of big blocks over the years but recently did the first for a jet boat! So we decided to run through how all that horsepower is turned into thrust on the water.

Water is drawn into the jet drive through an intake grate on the bottom of the boat. The impeller is directly coupled with the engine so if the engine is running, it’s turning and pulling in water. As RPMs increase, water is drawn in faster and the impeller forces it into the nozzle at a higher pressure creating thrust. More engine RPM will create more thrust and push the boat faster.

The reverse gate allows you to control the direction of the thrust. With it covering the nozzle it directs water towards the front of the boat, pushing the boat backward. With it raised, the boat moves in a forward direction.

Steering is controlled by a cable. The nozzle has a swivel point to steer the boat left and right. The driver can also control the trim via a hydraulic cylinder that’s attached to the nozzle. It moves the nozzle up and down to control the bow of the boat during acceleration and cruising.