If conditions permit, it is best to become a licensed structural engineer. Nowadays, many people have obtained these certificates and then hang them in the name of some design institute. These design institutes pay a certain amount of remuneration every month. even if you don't change careers, you can get two shares of money, which is pretty good.
If you have any questions, you can visit: Marine Engineering and Ship Technology Consulting Network to ask the answers you need.
One more sentence: Qualifications in the offshore oil industry are much more important than certificates.