I've lived in my house for 4 years...and in that time, these maintenance issues have come up. True, its an old house (1956)...but I see no difference in the monthly maintenance of a house and a boat.
Roof repairs - $2000
Window pane replacement - $500
Cutting grass/landscaping - $100 per month
Powerwashing - $200 each time...need to do this 2 times a year in FL
Dock piling repair - $1800
Dock staining/sanding - did this myself, but still $200 plus a weekend of time
Painting exterior of the house - $2800
Sinkhole formed in my front yard - $1200 for "pinning"
Driveway sealing/maintenance - $500 a year
Terrazzo repair - $800
A/C Service - $200 annually (and thats cheap)
Electrical work (lost fixtures and had dimming lights) - $1000
Endless *THOUSANDS* on permits and fees to the wonderful city and county I live in
PROPERTY TAXES - $4000 a year

and thats down from $9000 when I moved in.
Boats just seem to have the same maintenance, but at least I can do the work mostly myself. Everything from bottom jobs to port replacements. With code enforcement so bizarre here...I have to hire out the work on my house.