Maritime navigation covers many trades: apart from the ocean-going trade it also includes towage, offshore, dredging, etc.
Modern navigation consists of short voyages, which means that seamen remain 3 or 4 months at sea (or shorter, depending on the ship).
Mariners enjoy several months of holiday per year and they build up their careers faster than ashore. At 30 you can already be captain or chief engineer.
You don’t have to sail till you’re 60 years old. After a career at sea, many merchant marine officers take on a job ashore.
Thanks to their experience, they easily find a management job in the maritime industry , at port related companies, at public authorities, etc.
The maritime industry’s demand for former seamen largely exceeds the supply. Therefore, after your career at sea you have a choice of employment opportunities.