ok, I didn't realize that, but makes sense now, why you were looking at a 2.5 hp, I likely go with mid of the range, 5 or so, two stroke will be lighter than a four, but they are getting closer in weight every year,
A little electric may also work quite well, I have a 55lb thrust minkota on my old boat in Canada, a 17 foot lund, with a 115hp out board, and it pulls at along (Bow mount) at a very good clip. 10-15 km hr at a guess. runs for hours on a car battery.
Bookmarks