many of us now carry a CPAP machine when we travel.  But many find themselves unprepared when they bring one on vacation. With that in mind, I offer the following advice.

1) depending on the ship or line, there may or may not be a receptacle near the bed.  Make sure you bring a power strip, WITHOUT a surge suppressor.  A new extension cord should be packed also.  

2) you don't need distilled water for the week.  You can use the ships tap water. The ship processes water for drinking, and in turn, removes the minerals that might damage the heating element.  Clean the tank thoroughly when you get home, but for the week, don't worry about it.

3) if you sometimes have a stuffy nose, place a drop or two of eucalyptus oil in the tank. It won't damage the plate, and it will be like a blast of Vicks VapoRub.  

4) pack it in the original nylon bag it came in, and keep it with your carry on luggage. Not in your carry on, with your carry on.  You can usually shove a few extra items in the case.

5) if possible, leave the water tank home for the week, and just carry the main part of the machine. It's the air pressure you need, the heated water is a bonus.

6) you may need to contact guest services ahead of time.  I never have, but I have read where some people do. 

7) lastly, check with your Cruiseline AHEAD of time to see if there is anything else you need to do.