Well, soon maybe. In my apparently Quixotic quest for a single fuel for vessel, tender and toys, I keep looking for new ideas. Using propane as fuel for an internal combustion engine is not new, but it is for a modest outboard application. A company I can only identify so far as Marine Green (more on that later) has posted a video on YouTube that shows a small outboard running on what appears to be propane from a recognizable tank near the transom.
To quote the YouTube poster, “The ongoing progress of Marine Green’s R&D program. Propane is a better alternative fuel than other fuel sources. Safe, reliable, it does not go bad, and emits much fewer harmful emissions than gas… ” Here’s the video:
Is propane really a good fuel to use for your outboard? Possibly. We’ll have to wait and see Marine Green’s final performance and emissions numbers, but we do know a little bit about propane, generically, as a fuel. Check out the table below to see how propane ranks in terms of its energy density.
Btu Content of Common Energy Units
- 1 barrel (42 gallons) of crude oil = 5,800,000 Btu
- 1 gallon of gasoline = 124,000 Btu (based on U.S. consumption, 2008)
- 1 gallon of diesel fuel = 139,000 Btu
- 1 gallon of heating oil = 139,000 Btu
- 1 barrel of residual fuel oil = 6,287,000 Btu
- 1 cubic foot of natural gas = 1,028 Btu (based on U.S. consumption, 2008)
- 1 gallon of propane = 91,000 Btu
- 1 short ton of coal = 19,988,000 Btu (based on U.S. consumption, 2008)
- 1 kilowatthour of electricity = 3,412 Btu
You can see that propane has about 26 percent less energy in a gallon than a gallon of gasoline, and nearly 35 percent less than a gallon of diesel. That means that you’re not gonna get as far on a gallon, but if range isn’t an issue and if you’re already carrying and monitoring propane availability, it might be a solution. It’s hard to tell what size outboard is in the video; but I might be anywhere from a 9.9hp to a 25hp unit, based just on appearance. We’ll have to wait until the company’s website is up and running to get more details. I have also reached out to an individual well-known in passagemaking circles to confirm a rumor that he is at the center of this project. I’ll let you know what I hear from him.
Ultimately, I would still like to see someone like Evinrude take one of its multi-fuel E-TEC models and just certify it for diesel. It will already run on the stuff, as well as practically everything else out there; from gas to Jet fuel. Yes, I know diesel fuel is harder on an engine and it would require beefing up key components, but there are a LOT of diesel-powered yachts out there who would love not to have to carry gasoline for their tenders and dinghies.
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