Jet boats are powerboats propelled by a water jet system rather than a conventional propeller: an impeller draws water through an intake in the hull bottom and expels it at high velocity through a steerable nozzle at the stern, providing both thrust and directional control. Because no drive components extend below the hull, jet boats can operate in water depths that would damage or ground a propeller-driven vessel.
The shallow-draft capability makes jet boats well suited to rivers, tidal shallows, and areas with submerged obstacles. They accelerate quickly and respond to helm inputs with minimal lag at speed, which makes them practical for white-water river use, rescue operations, and recreational use in confined waterways. The steering mechanism depends entirely on water flow through the nozzle, which means directional control is lost when the engine is at idle or cut — a handling characteristic that requires acclimatisation. Stopping distances are also longer than propeller-driven boats of comparable size, as there is no propeller drag to assist deceleration.
Efficiency at cruising speeds is lower than shaft-drive propeller systems, and fuel consumption is correspondingly higher for equivalent speed. Impeller damage from gravel, debris, or sand ingestion is a maintenance consideration in silty or debris-laden water. Jet units can be paired with petrol or diesel engines across a wide range of vessel sizes, from personal watercraft to patrol and commercial vessels exceeding 15 metres. Repair costs for jet drive components are typically higher than for comparable propeller installations.
