This from the marine industry.
http://www.unitedmarine.net/blog/ind...thanol-update/
The marine industry has been dealing with f-glass tanks dissolving (leaking) and spilling into the bilge frequently being pumped over the side by the pumps with E-10. Since all these tanks are vented and sitting throughout the winter months phase separation is taking place as well with many visits to the engine shops to clear the lines and tanks. Rotax and others are accepting E-10 but E-15 will be too high a concentration. Each state decides how much fuel is blended with ethanol and what grade. Personally I and many other fuel users would like to see 91 rating fuels be ethanol free and keep the E-10 on the lower octane rated fuels. As an aside - high performance boaters are buying 100LL for their engines.