I actually did some radio playing on an Alaska cruise recently. I
carried a ft817, vx2r, and a 7600gr aboard with no problem. If you plan
to do any transmitting on board a Princess ship, they want you to have
permission of some sort. This permission involves faxing paperwork to
them and you should plan on at least 30 days for the process to complete.

I chose to do none of this. I just took my stuff on board and operated
from secluded areas on the upper decks. No one bothered me. Operating
2m repeaters with the vx2r was even easier. FRS radios are ubiquitous
on board so no one even noticed what I was doing.

There are some caveats to hf tx/rx on ships. If you are cheap like me,
you will be in an inside cabin. There is absolutely no radio possible
in an inside cabin. Thus you must be out on deck with the rest of the
passengers. You will be very limited in what you can do with antennas.
Built in whips that are not excessively long will be fine. Wires or
free standing antennas are probably not going to happen. If you have a
balcony, you may have a little more flexibility with antennas, but since
cabin staff are constantly fluffing your room, you will want to break
down your antennas when not in use.

Also remember that ships are very noisy. There is electronics
everywhere, and RFI is an issue. If you have to roam the decks with
your radio, be aware of ship's antennas. They are everywhere. It would
probably be a bad idea to tx/rx in close proximity to any ship board
antennas, particularly if you are trying to be low profile.

I found I enjoyed the MW reception on board as I got to hear some stuff
that I don't get to hear at home. It was also fun to hear locally what
I usually hear as dx. Lastly, if you have one, take a small scanner.
It is fun to hear the ship communicate with some of the local boaters.

And remember you are on your cruise first and foremost to drink. I'll
have what the gentleman on floor is having and bring one every 10
minutes until after I fall off my chair. After that, bring one every 20
minutes.