Hi, tfm01! Welcome to the DIS from a fellow New Jerseyan.
You don't say when you're cruising, but perhaps there's still time to get him potty trained! We told my granddaughter that we wouldn't even start to think about a cruise with her until she was potty-trained (she had overheard us talking about the reservations and so on). The next morning she told us she was potty trained, which we greeted with some skepticism since she hadn't even started the process). Well, never doubt a three year old who wants to go on a cruise! That was in early February of this year, and she's been trained since that day. She's cruising with us (and her parents and her favorite aunt, uncle and cousins) on Dec. 7!
Beth