deducting cost of cruise for tax purposes?

10 full days left and counting until I leave for my first cruise -
Caribbean Princess for a full week out of San Juan.

As an afterthought, I found myself wondering if anyone has ever
successfully deducted the cost of taking a cruise on their income taxes?
I've heard that some people do things like that - take a vacation, and
figure out a way to deduct the cost of the trip from their annual
income, or something like that. I've never tried, so it is almost a
foreign concept to me.

The only reason I ask is that I do freelance writing, and my editor
just asked me to do a couple of stories with a short deadline. (for a
magazine) It looks like I may end up doing the bulk of the writing on
the cruise - when I can finally get some time away from changing
diapers, and taking care of kids.

Is that sort of thing enough - having an article, and proof of
payment, along with a deadline that is shortly after the cruise date?

If you have any suggestions, I'm all ears!