30 million dollars...
Better start saving my pennies.
And rule of thumb is 10% of purchase price per year to maintain. That doesn't include fuel, staff, food, supplies, etc. Captains are normally $1,000 per foot/yr. So, figure 130,000 just for the captains salary. That goes to his/her bank. While on board all their food, clothing, etc. is paid for.
Then, after a captain, you'd need a engineer (another 100k) and 2 for deck crew. So, 4 just to keep it maintained, docked, the 4 would be washing and maintaining the boat constantly. Deck hands get 40-60k per year, depending on experience and job. Usually when they find good deckhands, they end up paying more to keep them.
With people on board / the owner and guests, you add a chef, server (two for a big group), and housekeeper. Chefs are expensive, I know a few making 100k a year. If in a place like Miami, Ft. Lauderdale, St. Tropez, Malta, and other boating destinations can usually get temp ones, but, still expensive for the week or whatever to use them. Sometimes one of the deck hands or crew members double as a chef, then just for fancy stuff at night they hire someone.
Also have docking fees, electrical, etc. Not sure what rates are around the world, but, here its between $3/ft - $10/ft per night, depending where you are. That's per night. hehe.
It's incredible the cost of ownership. I always tell people to charter. Yes, you pay $50-60,000 for a week (maybe 30k for just a weekend), before fuel, food & utilities, but thats nothing compared to owning one.
*Source: Grew up working on them