I have one of the cheap $60 electric trolling motor on my walker bay that pushes it along well. I use a 24"x24" roll up solar panel to charge the battery. Even thou its not for salt water it has held up over 2 yrs. want to sneak up on someone this is the way to do it
I also have a Nissan 3.5 2 stroke that's very light.
Both are only used when the capt. is in the dinghy other wise I row and find no out-board to be the lightest.