You would be going into business with two people who do not share your concern or financial interest in your boat - the captain, and the customer. Not only is there maintenance, but wear/tear and depreciation. What happens if the generator dies? Or a raw water impeller crunches and the engine overheats and blows the head gasket? The AC unit stops working even though its almost new? Is that maintenance? Normal wear/tear? Scuffs from docking - does it get a quick buff and paint so it passes the 10-foot test, or does it get a professional repair at $5k? What happens when stuff gets lost - you are 90% sure it was there, but can't prove it? You are pledging a $400k asset, what is your protection against a disagreement with the 100T guy, especially since he will have physical control of the boat? Your interests are not wholly aligned.
If you're interested in chartering your N42, find a reputable charter operation with proven maintenance program. Its a highkt desireable boat for charter and you should expect a warm reception.
A 100T license gives zero indication of experience and capability, just that someone says they spent 720 days on a vessel in some capacity (assuming their sea time is legit). And certainly says nothing about their integrity or marketing prowess.
While not a charter business, I effectively went into a boat related business with a marine company to restore my Willard 36. All was fine for a while. In the end, they admitted they owed me money, admitted the work they did was garbage. But they were unable and/or unwilling to make it right and were seemingly fine with my building a website describing what a bunch of hacks they are. Took me a while to unwind from them because they had control of the boat. Really bad feeling on my part.
Www.NizaMarine.net.
Lots of downside risk. Not much upside for you.
Good luck.
Peter