Another Electric drive small sailboat

seandepagnier,
relatively small props at sailboats is a result of compromises: large bronze porp is too heavy, large carbon prop is lightweight but easy to break. In any case large prop is easy to reel in fishing net or seaweed. Also, short waves at heavy weather will bend carbon propeller blades, this will impact in efficiency. I have no doubt large props is better for efficiency, but real world does not only demand maximum efficiency. As for sailboat Kaplya - there are installed as much large prop as fit under hull - 12". We got a 2 kW power at 600 prop RPM. This is not bad in terms of efficiency.
Meanwhile, Kaplya sailboat was used often since converion and owner still like the new drive.