Our first charter with our children was when our first born turned 9 months old while on charter. 41” catamaran. We charter all the time with them now and they are 3 and 5 years on a monohull. Different ages have different pluses and minuses. Retrospectively, chartering with an infant is easy...they can’t go anywhere. Bring your routine child care basics. We always slept our little ones in portable pack and plays when they were small. Particularly, the Lotus travel crib. Small, light and travels well. We put it on a bed. Get a good life jacket. We didn’t always have her in it while on the big boat, but ALWAYS while in the dinghy. We made the great harbour to white bay trip on the dinghy with no issues. Go slow if needed. We packed a portable sun shade we could use on the beach, a beach parachute type sheet, etc. Get good sunblock. Long sleeve UPF tops are great then you only have to sunblock the face, neck and legs. Consider a reusable swim diaper or no diaper for large portions on the day depending on last poop. Who cares if they pee on you? Limits diaper use and frequent changes because they get wet all the time. Always have PFDs on the parents too. We would try to time sailing when she would nap. We kept sails shorter then we would optimally like. If we knew we had 2 hours to sail. We might head out and for little, put her down for nap underway, and she would sleep for an hour or so, and then we would be moored and ready to play. That’s about it for now. Feel free to ask any specifics if you want.