450km is approx 250 nautical miles, so to achieve this in 10 hours, you will need an average speed of 25 knots. A boat that can average 25 knots in flat water
/ light wind
is a different beast from one that can average 25 knots in waves/chop and strong wind
. Your average 36' flybridge cruiser could do 25 knots in good conditions but would struggle in a decent sea. A 36' flybridge cruiser would use around 20 gallons per hour at that speed in good conditions, and more in rough conditions.
Dunno if that helps?
Frankly, you'd be cheaper to fly!