How does a jet pump work in a jetski?

It works like a centrifugal pump- centrifugal force impels the water and pushes it out the stern, creating thrust- in that sense like an airplane jet. on the other hand this is water and no combustion takes place in the turbine, which is driven by a conventionsl piston engine. Unlike its forerunner, the Sea Sled- the Jetski cannot ( at least intentionally) submerge. It is like an aquatic motorcycle- not a mini-sub.