Before getting into the landlord discussion, for which I have tons of experience, let's first recognize that the vast majority of live aboard cruisers return to land. That's not the way it seems reading magazines and web forums, but it's clearly true. If you'll have the means to return elsewhere, then selling is an option. If not, you might consider keeping it as a safety net of sorts.
As for being a landlord, you must first detach from any sentimental connection. It's now an investment property. IMO, you must have a local rental/management agent. In my area, they will take one month rent at each lease signing, plus a management fee. Be sure to consider repairs in your budget and a vacancy rate. If it remains cash flow positive, or you can swing the shortfall, it's an option.
I've had reasonable experiences with this approach. I believe the better maintained you keep the rental, the better the tenant will treat it. Give them one excuse that you don't seem to care and they will triple down on it. Still, expect some crazy behavior from what will appear to be normal people that just won't treat your property like it was their own. I also tried to keep my rent a few bucks below market, so I could be more choosey on who I accepted. Better jobs, more likely to remain in the area, etc. I've had tenants that renewed for many years. But, I also had one that called me from Detroit, about 6 months after moving in, and said he left last weekend, isn't coming back and isn't paying.
Be prepared for anything.