I drove so the TSA flying guidelines didn't apply to me. Carnival does have a 4 inch blade restriction, as far as the metal detectors, they seemed like more of going through motion then anything. I wore my G-Shock watch and belt through it, didn't go off. The watch alone sets off airport dectectors. I believe they look for alcohol, guns, bombs etc- more "extreme" weapons if that makes sense, and alcohol so you buy theirs.

They do x-ray when you board everytime- I believe Jamaica was the only port that x-rayed before you left the port, then again on the boat. I kept my firestarter in my bag with no issues, carried first aid, meds, anti-bacterial, insect repel wipes, flash light, couple of lighters and had no issues.

I would have liked to taken more but sadly was completly unprepared- luckily nothing more then anti bacterial was needed, but i do plan on cruising again and would like to be as prepaired as possible. I thought about MRE, need water purification, to name a few things- I opted ot leave multi tool in truck just in case. Since it was my first cruise and again sadly hadn't ddone my research, i opted to go lightly to avoid issues.