Here is another option for your CPAP that works without having to run an extension cord: There is a European 220V outlet behind/under the bed on most Princess ships (not sure about Island/Coral). In some cases it is unused and in other cases one of the lamps is plugged into it.   If you get an adapter, you can plug in both the lamp (if needed) and the CPAP.  (Most if not all CPAPs are dual voltage.) The downside is you might have to move the bed a bit to reach it on the first and last day.