Editing Jet engine (section)

===Water jet===
{{Main article|Pump-jet}}
A water jet, or pump-jet, is a marine propulsion system that uses a jet of water. The mechanical arrangement may be a [[ducted propeller]] with nozzle, or a [[centrifugal compressor]] and nozzle. The pump-jet must be driven by a separate engine such as a [[Diesel engine|Diesel]] or [[gas turbine]].

[[File:Pump jet.PNG|thumb|right|A pump jet schematic.]]
{| class="wikitable"
|-
!'''Type'''
!'''Description'''
!'''Advantages'''
!'''Disadvantages'''
|-
![[Pump-jet|Water jet]]
|For propelling [[water rocket]]s and [[jetboat]]s; squirts water out the back through a nozzle
|In boats, can run in shallow water, high acceleration, no risk of engine overload (unlike propellers), less noise and vibration, highly maneuverable at all boat speeds, high speed efficiency, less vulnerable to damage from debris, very reliable, more load flexibility, less harmful to wildlife
|Can be less efficient than a propeller at low speed, more expensive, higher weight in boat due to entrained water, will not perform well if boat is heavier than the jet is sized for
|}