That’s wildly inaccurate, even as a rule of thumb. Upkeep (excluding storage, which varies widely by location) shouldn’t be over 10% of the purchase price, unless the boat was really cheap or the boatyard doing the maintenance is crooked.
Talking US rates here, I have no experience overseas.
Bambi meets Godzilla is about 15 seconds long. It’s opening credits and closing credits are about 10 minutes total.