Potientally a tough one
If you haven't already - scroll down or page back to a thread called "links to cruise employment" that I started a while back.
Being a US citizen kind of restricts you on most cruise lines, but perhaps NCLA (that's Norwegian Cruise Lines US flagged ships in Hawaii), you might have more of a chance getting in with security or 'labor' related jobs. http://220.127.116.11/employment/nclAmerica/index.htm
. If you dig - there is a Surveillance Operator position that you might be qualifed for???? (and it's HAWAII!!!!!!)
For most any other line, you're going to have to have a specific talent, skill or education to get a job. On the marine side, I've only seen one US captain, and several Environmental officers - but these require serious maritime school training. Another choice is in entertainment - cruise staff or entertainer. Cruise staff are the outgoing people who host and meet and greet - knowing how to chat on the mic and maybe host line dancing would be basic requirments.
More . . . . be a shopping guide or art auctioneer - again, need to be able to chat on a mic (both of these are basically info-mmercial type jobs)
Most of these gigs require video auditions . . .
digging around some more . . . scuba instructor, translator, IT
I remember working with a Brit (aged 40ish) who had a security background and was a scuba instructor. He was working as a cruise staff - ended up going into the "private sector" as security about some very weathly person's yacht sailing the Caribbean . .