A guy on one of the smaller lakes I fish just got a new Merc Electric. I saw him come out of a cove and pulled beside him and we talked about it while running. Here's the "kicker:, he didn't have any way to measure speed so I took his phone and downloaded a speed app. He took the phone back and hit full throttle and it reached 12 MPH and was almost on plane. (he had a small 12' alum flat bottom) When running side by side at 5 MPH my 9.9 4 stroke Merc was almost as quiet and his electric Merc. My Merc tops out at 24 MPH on the 12' MirroCraft I'm running.
If I was going to limit myself to a single body of water or only small lakes I'd think about an electric OUTBOARD. They wouldn't work for me because I like to go MILES up different rivers fishing and exploring.
But that's just me........