My boats are paid for (luckily), and so I know my slip fees, club fees, obligatory restaurant minimum, and insurance is about $4,800/year. The insurance for my 41 foot steel cutter is $1,400, but that is for April-October in the water, and November-April on the hard.
Ongoing costs tend to be on a 'project" basis, as I am refitting for long-term voyaging. A new suit of sails will cost about $7,000, as will an engine rebuild (if one is necessary). Assorted fabrications will cost $5-7K, and a complete solar set-up will run $3K, plus a couple of grand for loads of truck batteries.
As you can see, equipping for offshore can mean a lot of money, but they are once in 20 year costs (sails offshore are once in six to eight years if you baby them). I am doing a lot of the work myself, however, and so am saving labour costs.
I don't even count rum!