But what's the HP? A general rule is Diesel engines consume about 1 gallon per hour for every 18 hp used. If you multiply 18x34.3 that's about 617 HP used (or less than 50% rated power).

You can also estimate the number of gallons consumed per hour by multiplying horsepower used by 0.055. The key is the word "used". If you don't use full power you will burn less fuel. That boat has a total of 1370 rated HP, so at full tilt it would be theoretically burning 75 GPH. About twice the number above.

If you've got the budget for that boat, the money for fuel probably isn't an issue.