My husband and I brought on a case (24 bottles) of water for a 7 day cruise. We didn't pack it and just left it in the original packaging. It was delivered with the rest of our luggage. He also brought on a 12 pack of soda.
We brought our small collapsible cooler when we cruised in October. We only brought it to the pool and kept beer and ice in it. We would order a bucket of beer and the servers would pour the ice into the cooler for us. We were able to bring on a case of water, a 12 pack of soda, and wine. We didn't pack the water and we were worried it wouldn't show up but it was delivered with the rest of our luggage.