Private yacht is a very broad concept. Therefore, this question should be answered separately and in detail.
First of all, there are exploration boats in the yacht category. The positioning of this yacht is ocean exploration, and even some models are specially prepared for polar exploration. Generally speaking, they are larger, more than 100 feet (33 meters), and some luxury configurations, such as swimming pools, will be sacrificed in exchange for more airworthiness. Some super large ones will even be equipped with a full set of medical equipment, including the operating room, in case of emergency.
This is where you can go if you have money. "Money in place" = start at $10 million without capping. The annual maintenance and use cost is also $1 million. Of course, the safety of what network equipment and what navigation basically do not need to be considered, because it is also a professional captain rather than a ship owner who sails. As for pirates, don't worry too much.
Compared with exploration boats, sailing is the choice of more people. The first is cost friendly. If the sailboat goes to sea, "money in place" quickly shrinks to the level of $100000, and the annual maintenance and use cost can also be calculated on the basis of $10000.
This kind of ocean going sailboat can basically take you wherever you want, but compared with the power boat with a complete driving and operation team, the sailboat needs to be driven by the owner, and the experience and technology are still very high. In addition to the monohull, you can also choose catamarans. The purchase and use costs of catamarans of the same grade rise to a certain extent (after all, there are two hulls).