It will help keep the fuel "fresh" over off season storage but it doesnt do much for in season fueling. No alcohol in ethanol free, obviously, so there isnt a water component to worry about.
I put my boat to sleep last week for the summer because of the drought. Spoke to a few mechanics and they have me doing it a little different. Instead of filling boat to 80% full, and add stabilizer, they wanted me to run it down to as low as it will go and add a stabilizer. I ran the engine with the stabilizer and 3.5 gal of remaining fuel to get it into the engine well and thats it. IF we have water next year, ill be able to add fresh 28 gal of fuel and should be good to go. But IF we dont have water and it has to sit on the lift longer, I only have to worry about 3 gal of gas in there vs 28 gal of gas. Both mechanics did not have concerns of breakdown of the fuel since hopefully ill be adding 28 gal of fresh to mix with it.
Washed it, put the playpen cover on it for the first time, opened up the seats and floor storage for ventilation and then tucked it in tight inside its Touchless cover. It sits until we get water.
Lets just hope we get water next year and I can run it.
I currently add Stabil 360 Marine to the cans before filling them with non-oxy fuel. It's most likely over kill, but
a) I don't have a trailer
b) nearest repair shop is 20+ miles away
it's cheap insurance to prevent fuel related issues.
Next year I may switch to using regular unleaded and add Stabil/Yamalube and ring-free