Jet Ski Rage is a cancelled sport / racing game that was in development by Velocity for the Sega 32X add-on. The game was going to be something like Wave Race but in first person view, with detailed water physic and a rumored multiplayer mode. Jet Ski Rage was likely canceled early in development as the failure of the 32X became apparent shortly after launch and then moved to Sega Saturn.
In the process Velocity added a “fighting” component to it (deadly courses, floating spikes, bounty hunters etc.). Even on its Saturn incarnation Jet Ski Rage would never seen the light of the day for unknown reasons.
Celine was able to find some screens of the 32X version (probably target-renders) in CD Consoles magazine issue #7 while the Saturn article was found on Sega Vision issue #25. Thanks to Jason for the english corrections!