Retirement is not very voluntary in this industry, in my experience. The majority of the tugboat captains I have encountered are not in good health and lose their annual USCG medical approval before 65.
You're not really selling the job very well. I often hear about how people used to jump at job opportunities like this or working on pipelines or other infrastructure that required them to work remotely, and I wonder if there's some nostalgia colored glasses there, or if these jobs used to pay a lot better in inflation adjusted terms. Or if maybe there are just better employment options these days.