If you’re a nudist, you’ll want to act fast on this travel tip. The first nudist cruise to the north, which takes place next July on Holland America's Amsterdam, is reportedly filling up fast. The Inside Passage cruise is said to be 70 percent booked.

If you’re not a nudist, you’ll want to steer clear of this cruise, where passengers will only be required to wear clothing in the formal dining area and when the boat arrives at the various ports along the way.

Now, I have absolutely nothing against nudists.

I’ve written about nude vacations before, and I consider myself to be pretty open-minded.

But as a consumer advocate, I also know what can happen when nudists and non-nudists mix. Or when your moral standards don’t match that of the other passengers, for that matter.

Case in point: the family that e-mailed me in March after it found itself trapped on a theme cruise for “900 gay porn models, actors and their fan club.”

“They advertised their films, had calendars hanging up of their models, did obscene things in the hot tub and pool and the children's activities area had to have the windows blackened due to them taking over the pool and hot tub just outside the kids area,” the concerned mother wrote to me.

The cruise line’s response?

So far, despite repeated attempts to contact it, there has been none. But I am optimistic, which is why I’m not naming the cruise line. Yet.