Up until 7 years ago I spent summers cruising my twin diesel boat (sold in 2015) thought the waters of Washington State and British Columbia, Canada. My fuel capacity was 440 gallons. I would anticipate using 1,000-1,200 gallons each summer. Just for giggles, today I checked the marine diesel fuel price in the Seattle area. $7.29 plus tax!!!!! (Road tax is not charged on marine fuel but sales tax is) This is CRAZY-NUTS. Depending upon cruising speed I would get between 1 and 3 MPG. For a boat the size of mine, that was considered rather fuel efficient. Oh well, at least I still have my memories..... Jim