Elke

In the movie Douce Violence (which has several names, like Sweet Ecstasy, and Violent Ecstasy), Elke Sommer is hanging out with a bunch of playboys aboard a yatch.

Barefoot, she's hogtied while laying on her side, and is about to be sold off in a mock slave auction.

However, when the yatch catches fire later, Elke is left still helplessly bound while the flames grow all around her.

But she gets rescued, with a couple of the guys untying her on the main deck after being brought up from below. You can see this scene right here.