Applicants with hotel, restaurant, retail, cleaning, customer service, childcare, entertainment, technical or professional experience can often find an onboard department where those skills transfer. Previous ship experience can help for some positions, but it is not the only background employers consider.
Read the job description carefully before applying. A clear match between your CV and the vacancy is more useful than sending the same application to many unrelated positions.
Use the wording of the vacancy as a checklist. If it asks for customer service, supervisory experience, cash handling, food preparation, technical licences or a particular qualification, make sure your CV shows the relevant experience clearly and truthfully rather than expecting the recruiter to infer it.