How can I get job on big ship?

How can I get job on big ship?

Best choice- Graduate from the Merchant Marine Academy:
http://www.usmma.edu/

Or...

Learn a skill used aboard the kind of ship you want to work on and apply for the job with a shipping company.

I'm not sure I understand your question. You're looking for employment on a large sea-borne boat? I'm not sure that's a legal question, however your options include but are not limited to applying to a cruise line, joining the Coast Guard or Navy, or working in shipping or any variety of industries that utilize ships. Best of luck to you!

But do let me tell you if you want to go to school for doing any kind of engineering in marine or something.. you can have it here:

http://www.schoolanduniversity.com/study-programs/trade-vocational/marine-mechanic
Thanks!