[TOMT][Movie] Movie about old people sent on a cruise to die

Looking for a movie I saw in the mid 80's. My guess is that it was shot between 1970 to 1984.

I remember that part of the plot involved sending old people on a cruise but actually instead of a cruise they killed them.

Also remember a scene where a couple has sex on a bathroom stall and when she screams he asks "did I hurt you" and she says "no, the tiles are cold"