I usually bring my manual lever coffee machine (flair) on cruises. I use a battery operated grinder and fill my thermos with hot water from the bar. I have never had problems with security because nothing connects to the power points.
When I cruised NCL, I brought my own filter papers and coffee beans that were compatible with the coffee maker provided in the balcony room.
I will be bringing single use bottles of oil on my next cruise for my bread, instead of butter.