For some people it's a switch they can't turn off. I used to cruise quite a bit with a guy who had a 67ft 2 million dollar motor yacht. I was unemployed at the time and was basically the only person he could find that could get 2 weeks at a time off to go somewhere. He said all of his other friends who were uber rich like he was were too busy making money to take even a few days off to enjoy themselves.
We had a lot of fun on that boat, though I felt like I was cheating on my sailor identity. We once nearly swamped Larry Pardey on Talesin in BC with our wake. At the time he was my #1 sailling hero (I owned a wooden boat) though I didn't feel I could shout my admiration to him from the flybridge of this mega yacht going nearly 20 knots....
If you say career means continuity, then you are always going to be add odds with the concept of an extended cruise. Not sure we can help you there. As for if I will be as competitive when I return, as someone without a gap in my resume, I can say that in my market it doesn't matter.
That was a point I probably didn't make well enough when recommending retraining to a very high demand area. One of the reasons that I think it is a viable option for returning cruisers. is that the demand is so high in some areas that your certification and your ability to fog a mirror may be all that you need to get the job. I know that's the case with ultrasound and echo-techs right now.
Depending on your income requirements, some of the training programs only take a few months. EMT was only 3 months, and phlebotomist is also 3 months. Both are garunteed jobs right out of training, regardless of how tarnished your resume is. Though your driving record gets looked at as an EMT and for either I suppose multiple felonies might count against you.
While I'm focusing on the areas of medicine that I know of that are in demand, I know that even in the worst downturn there are always areas of specialty that are in high demand. Some don't require a lot of experience, you just have to look carefully and be flexible enough to choose a new career/job based largely on demand alone.
Also, I believe someone else mentioned that the service industry is very tolerant of switching jobs and gaps in the resume. I would believe that, and waiting tables, or kitchen/hotel work is available everywhere.