I lived on a sailboat for a decade: unless it's your lifestyle and you are very capable (read: Jack of all Trades), it's a major expense.
Moorage on a vessel of 40 feet is close to a thousand a month. That's not including hydro-electricity to the vessel, or water.
The bottom has to be repainted yearly if it's kept in salt water; finding a shipyard that can haul a big beast like that isn't easy, and it's certainly not cheap. Most yards charge by the haul : they charge a fee to get the boat out of the water and onto a waize or supports, and another one to lift it up and put it back in the water.
There's plumbing and electrical stuffs, dealing with a plugged toilet on a boat is a
nightmare that is not only gross, but can sink the boat if you aren't careful.
If you want a yacht, and you can afford it, you can afford to hire someone to take care of it and pilot it for you. Otherwise, you'd better be awfully capable.