I am offering lots in the way of flexibility. This is a very illiquid labor market compared to most industries. There are simply much fewer candidates. My company's biggest disadvantage is that we have very irregular voyages (we colloquially refer to this as "tramp steamer" work). This is in contrast to work in the oil industry, where a credentialed captain can work a very regular schedule and be guaranteed to see family regularly.

This means that our ideal candidate is likely to be very young or beyond the years where he or she might want to stay home more.

I inherited responsibility for running this company two years ago due to a death in the family right in time to face this demographic crisis. I find that most maritime companies that are not big enough to have a large labor pool are having the same problem. We are all competing for a shrinking pool of labor and doing anything we can to attract them.

[editing to add]

A lot of the retiring captains simply cannot unretire due to health concerns. A captain is required to have an annual medical certificate. Many captains in their late 50s have heart trouble and get removed from service. It turns out that spending 24 hours a day for 2-4 weeks at a time in an environment where one cannot get any cardio, sitting in a chair, and having plenty of food leads to heart problems.

A lot of the younger candidates sharp enough to pass the tests can get a much more comfortable job anywhere else. (I certainly chose programming because I did not enjoy being hip-deep in fish growing up on commercial fishing boats.)

We have researched this a bit. We are working with a staffing company that claims to know how to execute the process. It is not yet clear to me if we should be outsourcing this or trying to do it entirely ourselves.

Any ship using US deckhands will need US command crew (Jones Act). Immigration might open up deckhand positions, but not master positions until they naturalize.