At the marina where the boat is docked they have several of the big yachts (not super yachts, just big yachts) come in. The general rule of thumb is annual operating cost is %10 of cost at purchase. This includes crew, fuel, dockage, maintenance etc.
One of the 140' had a range of 800nm on 10,000 gallons. To go fuel up, 60 mile round trip, marina to closest port where a fast speed fuel pump is located (who wants to wait to take on 5-8k gallons of fuel at the speed of your local gas station) it would cost arround $3000 just to move the boat to spend $40k in fuel. I'm glad I don't own a boat, too ****** expensive.
Tommorrow I have to fuel up 'my' boat. Its $5.72 at my marina, $4.60 next port over. I think I will sail to the next port over and save $100.