Me, I've sailed small boats on a lake in good weather. I wouldn't go anywhere near open seas.
Similiar experience here. I've never sailed anything bigger then a J/24, I've never gone outside of the harbor, and I've only sailed in whitecaps once (Victory 21 under main only).
It sounds like there are a couple of people here with blue water experience, so I'm going to defer to them on what is/is not prudent.