Now this hits a little too close to home...we sailed on the Amazon this past April. I remember on one excursion asking the tour guide if there were or had been any pirates on the Amazon. He replied that there hadn't been, and there was no need to worry.
Here's an article from Travel Weekly regarding a recent pirate invasion...albeit on a smaller luxury vessel.
We were on what's considered a "small ship" in the cruise industry, but not this small. This ship was "dinky" in comparison. We were on the Pacific Princess, which holds about 650 guests (article and pics below).
I wonder how they would begin to scale a larger ship though? I guess that's their business to learn how? Yikes!
If you guys have an opportunity, I would sail the Amazon...it was unforgettable. I would think larger cruise ships would be more alert and have security measures in place.