So by the purist version of the definition a jet ski is just that, jet propelled. So is this Kayak application.Wikipedia said:A jet engine is an engine that discharges a fast moving jet of fluid to generate thrust in accordance with Newton's third law of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets and pump-jets, but in common usage, the term generally refers to a gas turbine Brayton cycle engine used to produce a jet of high speed exhaust gases specifically for propulsive purposes. Jet engines are so familiar to the modern world that gas turbines are sometimes mistakenly referred to as a particular application of a jet engine, rather than the other way around.
I'm going to venture a guess that there are a few guys on this board with 'Engineer' somewhere in their job title