I have own a boat for over 25 years, but they were all the small version, bay fishing boats, nothing over twenty feet. I have spent a lot of time on larger offshore boats and can tell you they cost a lot of money to operate and maintain. If you can afford it and will get a lot of use out of it, go for it, if not you might want to rethink it.
As they say, (and this applies to any size boat, the bigger the more money)
the two happiest days in a boatowners life are the day they buy the boat, and the day they sell the boat.
Also, the definition of a boat - a hole in the water that you through money in.