by GreenLake » Tue Mar 09, 2021 8:49 pm
My electric outboard uses .3hp in electric energy (there are various reasons why this isn't 1:1 compatible to the way hp's are measured for a gas outboard). My trolling motor used three times as much, or ~1hp electrical energy for getting to the same speed.
Those values define the lower bound on a practical power range.
5HP in my view defines a practical upper bound. I'm not sure it's enough to get the DS to plane, and therefore you'd be limited to hull speed. From what I've seen a fully loaded DSII do with a 2.5HP outboard, my guess is that somewhere past 3.5HP you get to a point where the additional power no longer makes the boat go faster through the water. (Theoretically, if you were motoring into a gale, you might need more power to reach hull speed, because you'd have to overcome the wind resistance as well).
My take would be that if you already own a 5HP you should be able to use it, but I wouldn't recommend you purchase one new: you'll be happier the less weight you hang off your transom. (I know that a 2.5HP works if transom mounted, but don't know if a dedicated motor bracket is indicated for a more powerful outboard)
Motor recommendations depend heavily on your usage scenarios. (The way you phrased your question, it focuses narrowly on what is possible, not what might be desirable or optimal. I've tried to answer it that way, but if you are still figuring out your requirements, let us know).
~ green ~ lake ~ ~