Remember................
...that most of the ships with the cruiselines are not American registered. They do not have to abide by American laws.
There are travel agencies that specialize in booking cruises for deaf people, including interpreters. You can get registered with some of these and they will inform you regularly of which ones will be interpreted.
I have been on many cruises. One had Bill Cosby as entertainer and I tried for months before the cruise to get an interpreter just for that show, with no results. So we did not go to Cosby's show at all.
About all I can suggest for your coming cruise is to have some close friends who can Sign go with you.