I have worked on cruise ships - and in fact they do like to hire attractive people for the cruise staff...
BUT - do not let your weight stop you from trying.
The cruise lines also strive to hire people that represent a cross-section of their customers - and these days your weight is not that unusual.
If you have a great personality, especially if you can show you are at ease with your own weight (maybe even have some really good jokes ready about it) then it could even work in your favor.
Remember - this is the entertainment business. If you are good at your job and healthy in other respects I actually think they might choose you to show how diversified they can be.
For those jokes - make them funny but not too "blue" or cruel. Clean but funny. Do a web search, you will find it.
Like if they ask you to describe your assets you can say "elephants never forget" - make it sound spontaneous, casually self-deprecating but not cruel and funny.
best of luck.