There is not a single gasoline marine engine manufacturer that allows anything over 10% Ethanol in their engines. If one uses a higher amount- warranty automatically VOID.
E-15 will not work in gas based marine engines. Why? Because of storage, phase separation, moisture absorption, etc.
We are long overdue for fuel efficient automobiles, in the at least 40MPG range. It could have been accomplished long ago but greed got in the way, along with arrogant attitudes by the manufacturers. Add in lobbyists for the auto industry and we are where we are today. VW is the perfect hindsight example. Not only did they do the diesel scam to make more money by claiming ridiculous unobtanium results, they also tweaked gas cars too, lots of them.
More Ethanol is NOT the answer. Building and selling fuel efficient cars/trucks is needed and long overdue.