hard as hell to get into as crew.

I would assume it is the same as any merchant mariner. Lots of licensing and training.

I was on the royal clipper a few years ago, it was great.

Many European navies have these as training ships and it used to be quite common that you could sign up as a recruit and spend some time on board. Probably easier than becoming a trained crew otherwise.

Many accept volunteers for the enormous amount of shore side maintenance work, and I’ve known several people who parleyed that into (low) paying work.