The December issue of the BooatU.S Magazine has a couple of interesting articles reading regarding marine gas fuels.
One is about Ethanol Myths that most of us have considered previously, that includes expertise from BP , Chevron and Mercury Marine: http://www.boatus.com/magazine/2011/december/ethanol.asp Note at the end Merc mentions E10 (NOT E15) is a pretty good fuel in that it allows the gas in tanks to "stay dry" as normal minimal amounts of water is pulled through water separators with the gasohol to pass through the engines without harming the latter.
And the second is about research into a potential (and related) alternate-alcohol additve to replace ethanol: Isobutanol.
http://www.boatus.com/magazine/2011/december/affairs.asp
No indication of relative end costs other than "potentially cost-effective".
Note that much of the summarized information below is from that offered in the article by Dave Munz,representative of GEVO Co. a publicly traded company (NASDAQ) who as a producer has strong interest in promoting isobutanol.
It reportedly has 30% more energy per unit than ethanol, does not bond to water to the same level as E10 so phase-separation apparently is not an issue (but a water separator would be more important again), is less corrosive so it can be run through a pipeline instead of transported by train & truck and supposedly can be used in higher % mix without the dire consequences of E15 use in marine engines.
It's solvent properties are weaker than ethanol so it might be safer in f/g tanks (and rubber parts?) but would likely not keep fuel systems as clean.
Preliminary testing in boats with O/B, I/O & jet drives indicates no increase in emissions or internal wear.
It should be interesting to see what becomes of this as more facts and tests are reveled.
One is about Ethanol Myths that most of us have considered previously, that includes expertise from BP , Chevron and Mercury Marine: http://www.boatus.com/magazine/2011/december/ethanol.asp Note at the end Merc mentions E10 (NOT E15) is a pretty good fuel in that it allows the gas in tanks to "stay dry" as normal minimal amounts of water is pulled through water separators with the gasohol to pass through the engines without harming the latter.
And the second is about research into a potential (and related) alternate-alcohol additve to replace ethanol: Isobutanol.
http://www.boatus.com/magazine/2011/december/affairs.asp
No indication of relative end costs other than "potentially cost-effective".
Note that much of the summarized information below is from that offered in the article by Dave Munz,representative of GEVO Co. a publicly traded company (NASDAQ) who as a producer has strong interest in promoting isobutanol.
It reportedly has 30% more energy per unit than ethanol, does not bond to water to the same level as E10 so phase-separation apparently is not an issue (but a water separator would be more important again), is less corrosive so it can be run through a pipeline instead of transported by train & truck and supposedly can be used in higher % mix without the dire consequences of E15 use in marine engines.
It's solvent properties are weaker than ethanol so it might be safer in f/g tanks (and rubber parts?) but would likely not keep fuel systems as clean.
Preliminary testing in boats with O/B, I/O & jet drives indicates no increase in emissions or internal wear.
It should be interesting to see what becomes of this as more facts and tests are reveled.