It'll "run" with ethanol, but it doesn't run as well with it and causes all engines to work harder. The biggest problems caused by ethanol don't have anything to do with "running" though. Ethanol gasoline separates much faster than non-ethanol leaving water in the tank. It also dissolves fuel lines and resins (especially in fiberglass).
Ethanol contains less energy than gasoline so naturally it's going to produce less power running E10 than straight gas. Ethanol doesn't separate from water, it's hydrophilic so it absorbs water, when it reaches it's saturation point the water falls out of solution and you get water in the tank. That's the reason it's not good to leave it long term in a tank especially in a humid environment. Straight gas isn't good to leave long term either, but ethanol's worse. It won't dissolve any fuel line on a boat or car made in the last 30 years, they've long ago changed the rubber formulations to be resistant to ethanol. Same thing with fiberglass resin, if ethanol is dissolving it you've got a really old boat or the resin wasn't properly catalyzed. Ethanol shouldn't affect it.
I don't like the stuff at all in gas (love it in the single malt I'm drinking now) but it's not going to hurt any late model boat engine just like it's not going to hurt any late model car. Your '66 corvette ain't going to like it nor is any boat motor from that era. If you're running anything built within the last couple of decades it's not going to make any difference.
