Yes, have done many in the past (when the money was better)....Lol.
Pretty much all what Andy and Stuart said above.
I did a few long stints when I was younger, Caribbean and World Cruises etc.
A great way to save money quickly and does wonders for your playing.
I mainly did the show/Orchestra gigs and a few Jazz trio sets, and the standard was pretty high.
I was fortunate enough to get the tail end of the P&O gigs as well,
where you could just do two week depping in the production show band,
Cruising around the Med, Canary Islands etc (In and out of Southampton).
Social life was good (great in fact), single or shared cabin was dependant on
what company or ship it was.
Met my wife on a cruise thirty years ago.
She was a singer dancer in the show I was backing.
Up and down the South American Riveria for six months.
That cruise was particulary good, because we used to get two
over nights in Rio and two in Buenos Aires as well. And we got to eat with
the passengers and use their bars, I am pretty sure that doesn't happen these days.
We have very fond memories of that gig...lol...
I have done my stint and loved it, but I wouldn't do it again.
If you are young, I would highly recommend it.
Certainly a way to get your playing, reading and busking chops together,
and get to see the World.