Most people can estimate, by way of their own experience, just how much fuel their car
or motorbike consumes in a day or week. But for a big business manager—or a lucky
millionaire with luxury transport to take care of—fuel cost estimates may involve bigger
and more expensive vehicles.
Basic fuel cost assumptions
The underlying principle is the same: fuel consumption of any vehicle or mode of
transport depends on how much horsepower that vehicle’s engine (or engines) carries,
and just how large and heavy the vehicle’s body is. The bigger the transport is and the
faster it needs to go, the more fuel it will consume per mile it covers.
It also helps to remember what fuel a particular vehicle uses, and how much it currently
costs per gallon. For instance, jet fuel in the United States cost as much as $4.24 per
gallon in 2009, while gasoline for cars cost $2.67 per gallon. Fuel prices, of course, may
have risen since then.
To get a better sense of scale, think for a moment about the fuel efficiency of a large
private vehicle, like a sports utility vehicle (SUV). Gas mileage for SUV’s can be
anywhere from 11 miles per gallon of fuel (mpg) to as much as 34 miles mpg. Then
compare that with the following higher-powered vehicles.
Private airplanes and commercial jets
Typical small private jet models weigh anywhere from 17,000 pounds (e.g., Lear Jet 35)
to 90,000 pounds (e.g., Gulfstream G-5). Again, the bigger the weight, the more fuel is
consumed per mile—and the lower the gas mileage will be. This is especially true for
airplanes, which need to maintain high speeds in order to simply fly.
The Lear Jet 35, for instance, will typically fly at 485 miles per hour. Assuming it carries
seven people including the pilots, this jet plane will need a gallon of fuel for every 4
miles it covers. On the other hand, the bigger Gulfstream G-5 which can carry about 18
people running at 530 mph requires a gallon per 1.3 miles.
As of 2011, commercial airline companies reported that jet fuel costs are currently over
$3.00 per gallon. Using this price, a private jet’s fuel consumption alone may cost at
least about $1,100 to $3,700 for a 3-hour flight—not counting any extra fuel burned for
take-off or extra flight time.
Not surprisingly, the amount of jet fuel consumed in a year by private jets, commercial
airlines, and military planes is staggering. In 2007 alone, the United States consumed
about 24 billion gallons of “Jet A” fuel. Private jets accounted for 2.5 million of those
gallons. The remaining 90 percent were from commercial and military planes. That’s
nearly $8 million spent on fuel alone.
Private yacht or speedboat
Estimating fuel consumption is a little more complicated for expensive “boats.” It
depends on what type of ship or boat it is, where and how it’s kept, what type of fuel it
consumes, and how it’s actually run.
First, small ships or boats that are kept in their own mooring space and dock will only
use fuel whenever the engine runs. But owners who must tow their favorite holiday
vehicle (typically at least 30-feet long) from their home garage to the nearest bay
sometimes about a hundred miles away must factor in the fuel consumption of the truck
or moving van that will take it there.
Secondly, some ships are large engine-powered sailboats which can harness the
natural power of the wind to augment traveling speed or do away with engine power
altogether at certain times. Other ships are small yachts akin to small cruise ships, or
high-powered speedboats, either one of which require engine power just to move a few
Thirdly, what type of fuel does a particular ship or boat consume, and how will it use it?
It’s either gasoline or diesel. Generally speaking, gasoline engines are more expensive
than diesel engines. Gasoline boat or ship engines use about a gallon of fuel per hour
that uses 10 horsepower; diesel engines use about a gallon of fuel per hour per 18
horsepower. Given water movement and the size of a ship, increasing the mileage per
gallon can be achieved by traveling across the water at a much slower speed.
To illustrate, here are a few examples. A typical 33-foot sailboat with a diesel backup
engine traveling for 300 miles at 7 knots (assuming calm weather) can get by on 50
gallons. However, that entire amount would easily be burned by a 40-foot twin-engine
“sportfisher” boat over a distance of only 33 miles if it traveled at 40 knots.
But how much would that fuel cost? As of April 2013 across the United States, for
instance, retail prices for diesel are currently averaging a little under $4.00 per gallon;
gasoline is selling at around $3.70 per gallon. Based on such prices, for every $200,
that same sailboat can take a leisurely 300-mile cruise in fine weather. Meanwhile,
the gas-guzzling speedboat would be gobbling up the same $200 for every 33 miles it
Floating cruise ship
The numbers become astonishing for companies running cruise ship-operations. In fact,
managers use statistics that are relevant to shipping: ship volume (tons) or length (feet)
per gallon (of fuel).
Today’s cruise ships can weigh anywhere from 70,000 to 93,000 tons including onboard
lifeboats and secondary vessels, and travel anywhere from 21 knots to a brisk 32.5
knots. Such ships are typically powered by at least eight or nine diesel engines. At that
weight and speed, and with that many engines, cruise companies tend to estimate fuel costs based on how many feet of water a ship can cover with a gallon of fuel at those speeds in knots.
One good example to use as an illustration is Cunard Line’s cruise ship “Queen
Elizabeth 2” nicknamed “QE2”. At 963 feet long, 105 feet wide, and 204 feet high, given
a gallon of fuel she can move at 30-plus knots for a mere 40 feet.
Of course, such ships typically log in hundreds, if not thousands, of miles. Since one
nautical mile is about 6,076 feet, a 252-nautical mile cruise on board the QE2 from Fort
Lauderdale in Florida to a port in the Bahamas would require over 38,000 gallons of
diesel fuel. That’s at least $152,000 fuel cost per trip!
In fact, a fleet of Hawaiian inter-island cruise ships can rack up at least $250,000 per
week just for fuel alone.