How to determine yearly fuel usage

dserrell · Dec 2, 2009

I would begin by asking boaters how many days per year they use their boats, and how do they use they boats. Then, how many gallons per day they average using! The type of boat, LOA, displacement, number and size of motors, would need to be categorized. This would be a perfect opportuntiy to develop a generic formula that might apply for figuring how many gallons a boater uses in a year. There are so many variables involved the process of coming up with at realistic answer will take some time. Good luck! Fair weather!

David

PS

A very basic and simple way to figure how many gallons per year would be: Classify the type of boat then apply the following: days per year x miles per day / miles per gallon = gallons per year!

Our Compac 19/3 sailboat might use 20 gallons per year based on using the following formula:

19' Sailboat with 5HP outboard = 60 days per year x 5 miles per day / 15 miles per gallon = 20 gallons per year

kloudie1 · Dec 2, 2009

I dunno, Geoff.. I’d ask for the number of gallons used.. most folks who sailboat can give you that number pretty accurately.. For instance, I know I used about 20 gallons because I haul it in 5 gallon jugs.. I know where the level was and I know it is about there right now.. ‘course, the year isn’t done yet and I’ll probably use another gallon before Jan 1.. If you are including powerboat folks I would do #1 and #2 .. some will know pretty much how many gallons.. some will know #2.. #3 is iffy ‘cause a lot of powerboat folks won’t be honest.. ya know.. kind of like asking a Toyota Prius owner what his fuel mileage is..

Ross · Dec 2, 2009

just ask! but then ask for details concerning the boat and the use. Most of the sailors I know would rather sail slowly than motor. This past May we went out for two weeks and had no wind or too much wind so we motored a lot. Some days we didn't even hoist the sails, but we motored slowly and used fuel at a very low rate.

Ron20324 · Dec 2, 2009

4) Some other snazzy way.

-- Geoff

Call BoatUS and see if they have the figures.

woodster · Dec 2, 2009

this sorta brings on a new question i would think.......How accurate is there log books???? i would think that info would be in there along with other stats..

Seattle Scott · Dec 2, 2009

I know average engine run hours a year

it has a hour meter and I know average consumption per hour .75 gal, so I know 100 hours x .75 = 75 gals for me.

doesn't really matter how often or how much boat is used, but anual engine run time and most people have done a average consumption calculation, fill up tank run engine and keep track of hours until next fill, then hours divided by gallons = ave gals per hour.

Ross · Dec 2, 2009

Re: I know average engine run hours a year

I log 10,000 miles +- /year in my car @ 20mpg. therefore 500 gallons. fuel consumpsion for the boat is based on number of 5 gallon cans I use /season. There fore most years less than 10 gallons.

petersea · Dec 2, 2009

Geoff, I think you might have overcomplicated the issue. I agree just ask how many gallons of fuel used. My bet is most people will be close (with in 10%) if they think about it but most would not bother to even figure the car usage. Bet most boat owners can tell you more about there boat engine then their car engine. Keep it simple......

Steve Dion · Dec 3, 2009

I have a log and can tell you exactly how much fuel we use. Normally we fill up 2-3 times a year. The fill ups are based on where we may be going. If it is just a short trip, I will only check the gauge to see where we are. If we are making a trip 5-15 hrs. I will normally fill-r-up.

tommays · Dec 4, 2009

Does your CO2 figure change with the engine type and Emissions level ?

kloudie1 · Dec 4, 2009

You betcha the CO/CO2 mix changes a LOT between gasoline, 2 stroke/ 4 stroke.. and diesel 2 stroke/4 stroke.. Typical normally aspirated 4 stroke diesels make very little CO compared to gasoline motors that are running without catalytic converters.. marine motors.. Any fuel containing carbon makes these things when the fuel is burned to extract the energy inside it. Basically every fuel we use today to any extent makes those products, including alcohol laced fuels and pure alcohol and biodiesel, natural gas, propane, etc.. Engines like the space shuttle mains make only water since they burn only hydrogen and oxygen.. Don’t think that plugging into shore power saves lot of carbon footprint because getting the power to your plug is pretty inefficient (there are significant losses just moving the electricity to the plug from the generator) .. and produces a lot of carbon and other things .. Nuke, wind, solar, hydro and a few other drivers for power are a little better, but ya have to factor in all the carbon that was released when the plants were constructed, and the requirements for maintenance.. Not being a nay sayer, just saying that the whole package needs to be included when looking at things like this.. Gasohol, a noted net loss project, is a result of not looking at the whole package.

tommays · Dec 8, 2009

I see the facts from the EPA and it may match boats powered with old tech but that does not match up with the claims form newer green motors

Moody Buccaneer · Dec 8, 2009

geoffschultz said:
It doesn't. The amount of CO2 produced is related to the type of fuel, but basically unleaded gas generates 19.5-19.9 lbs of CO2 per gallon and diesel generates 21.2 lbs per gallon. If you use Bio-diesel, that only generates 5 lbs/gal.

-- Geoff

Interesting numbers ... gas produces over 3 times its own weight in CO2 ... about 20% of the total exhaust weight?

Count me in for about 20tons for last year.

I'll probably be able to double my production in 2010! Glad to do what I can.

kloudie1 · Dec 8, 2009

I dunno.. It is time to get our Chem Engineer friends involved.. Biodiesel has only about 8% less carbon by weight in it per gallon than standard diesel (http://www.epa.gov/otaq/models/analysis/biodsl/p02001.pdf)
When ya burn it, it is going to make about 8% less CO2.. The carbon in it goes to CO2 and the hydrogen goes to water .. Like I was saying, there are other things to consider.. Again, here is a quote from the EPA report:
“Although it would appear from the values in Table IV.A.3-2 that biodiesel would have a
tendency to produce less CO2 emissions than conventional diesel fuel, biodiesel also contains less energy per gallon. Thus more biodiesel must be consumed to propel a diesel vehicle a given distance than conventional diesel fuel. In order to take the difference in energy content into account, we calculated the carbon content per Btu by dividing the values in Table IV.A.3-2 by the volumetric energy contents given in Tables IV.A.2.a-1 and IV.A.2.a-2. The results are shown
in Table IV.A.3-3.”
I am not saying that biodiesel is bad.. it does reduce emissions compared to regular diesel.. But CO2 is not reduced.
Gasohol.. Here is a quote from a US Dept Of Energy report:
“Combined Tailpipe and Evaporative Emissions

When both tailpipe and evaporative emissions are considered, Niven found that E10 showed increases in total hydrocarbon, non-methane organic species, and air toxic emissions, while substantially increasing the ozone forming potential relative to gasoline.”
Gasohol, E10 and higher level blends, has the problem of not having as much energy in it per gallon as regular gasoline does. It also requires more gallons to make the same horsepower. Not an easy problem to address..

Ron McCoy · Dec 8, 2009

Rather than ask boaters about their fuel use (you're down in the weeds IMHO), or cars, or trucks, or lawnmowers, or any other type of combustion engine, why don't you look at a more macro-picture? How about the quantity of gasoline distilled/distributed in the country. While its not all consumed immediately, over a certain period of time (90 days) you can get a fairly close approximation. The American Petroleum Institute probably has some fairly good estimates too. When you limit yourself to boats (or sailboats who use even less), you miss out counting other users - mega yachts to the small PWCs, bass boats, etc. Seems like a course in statistical or quantitative analysis is in order.

Moody Buccaneer · Dec 8, 2009

geoffschultz said:
I don't understand how these weights are calculated/measured. If anyone can explain how you can produce more this, I'd be very interested.

-- Geoff

Taking the number you posted: but basically unleaded gas generates 19.5-19.9 lbs of CO2 per gallon.

1 gallon gas weights 6.2 lbs and mixes with 14.7 lbs of air per pound of gas to burn efficiently. Total weight of mixture for 1 gallon gas is 6.2 x 14.7 (air) + 6.2 (gas)

19.5 - 19.9 is close to 20% of the total exhaust weight and about 3 times the weight of just the gas.

I can't comment on why anyone is measuring CO2 without getting this thread bumped.