What is the tons per mile per gallon of ocean going vessels?

Question

What is the tons per mile per gallon of ocean going vessels?

Answer 1

Like others have said, it all depends on speed, fuel used, tonnage, weather conditions...   The last ship I was on, a car carrier, used between 45-60 tons of fuel a day at 13-17.5 kts.   It was burning a cheaper type of diesel.   If we'd had the expensive diesel we could have reduced RPM way down and saved fuel instead of going in circles to let bad weather go by.   We needed to keep above 80 RPM though to keep the engine from building up too much carbon with the cheap fuel.    As a wild guess and many areas with possible mistakes I figured we burnt about 20 gallons per mile for a 600+ foot ship of around 45000 tons at 17 kts.   This was figured out on the graveyard shift with no paper or pen, so might be far off.

On LNG carriers we'd burn boil off gas which was basically free since we didn't have recompressors onboard.   It didn't have nearly the BTU per ton as bunker fuel does, but did burn hot and clean.

Answer 2

do you mean how is fuel consumption on ocean going vessels expressed?

Answer 3

My own ship, a 40,000 ton tanker, burns 65 tons of bunker-C (crude oil without the dirt and water, basically) per day, averaging 15.5kt. At sea (full cruise) speed, we produce 13,500hp. One must also consider fuel burnoff for our turbogenerators (steam-powered electric generators), too, however. That's part of the 65 tons/day.

The speed you want, shape of the hull, fuel you use and horsepower involved will determine fuel consumption. A container ship averages 23-25 kt, and seems to have between 25 and 60,000 hp for a handymax (small) and panamax (medium) hull. Their engines are more efficient than my ship's steam turbines, however. At 60khp, the last container ship I sailed on used about 75 tons/day of IFO 380- a more refined (and more expensive) black oil). Post-Panamax containerships (big, fast, efficient) are coming out with 100,000+hp diesels.

The goal isn't to minimize fuel costs, it's to maximize efficiency. I can move gasoline, diesel, etc, at only 15.5kt, but it's cheap at the cost- about $60,000/day including fuel. This adds only about 1.2cents/gal to the price at the pump.  Pushing the speed higher gets inefficient when compared to fuel costs. Running at a lower speed creates the risk of large price fluctuations at the retail level when compared to production costs. My charterers want their cargo to get to the discharge port relatively quickly, but they don't want to pay too much... BUT, if the price drops, they lose money- a 5cent/gallon price drop hurts when you've just purchased 10,5 million gallons!

Answer 4

I am on an ocean going tug and it burns 208 gallons per hour at full rpm. It will make 8.5 kts in still water,  moving a barge loaded down to 25 feet with 85,000 bbl of #6 oil.

Answer 5

That varies massively depending on the engines type and power.  Size and shape of the hull. whether the ship is hauling *** or moving at it's economical speed. the economical speed is the fastest the ship can go without guzzling more fuel per horsepower than you get back in speed. The hull gets less efficient due to drag as the ship goes faster so more and more power is needed to move say one knot faster may cost you an extra 10,000 horsepower after a certain speed. that speed varies with the ships hull shape.