I have sailed twice while breastfeeding, once in 2013 and once in 2018 (different kids, obviously). The nursery will take pumped milk and give you back the used bottles dirty. I used the bathroom sink (the bathroom with the shower, not the toilet) and a tiny portable drying rack for washing parts. I never brought the babies to adult only areas. I nursed freely everywhere else I felt like it-- sometimes with a cover and sometimes not. I'm pretty small chested so easy to be discrete and relatively modest. I never had anyone notice or care. I never had an issue in ports but we were always just at beaches. At dinner, the assistant server (female) cut my food for me once or twice when she noticed I was having a hard time eating while nursing which was cute (she volunteered...I never asked). Honestly, I think this is a very non-issue if you've made it to six months of nursing.