Spring Break USA

Janine Lindemulder stars in Spring Break USA as a heiress who gets kidnapped.

Near the end of the film she's held captive aboard a yacht with her hands tied in front and with a nicely tight gag. All while clad in a nice bikini.

She's tied to a chair earlier in the film, not not gagged. This scene is the only one I have a clip of, and the clip is very brief, just seven seconds long. Short and sweet. You can see it right here.