RE: 4 stroke boat motors??
There have been Model 4 strokes for marine in the past. I believe OS had a few. Don't know of the current availability. Displacements were around a .40 I think.
It's true that a 4 stroker does not have the rpms as a 2 stroke, But like other motors, electric included, some types provide more torque, thus able to swing a larger prop.
The same holds true for a diesel, which I have seen in the past.
I see nothing but possibilities for a 4 stroke in a scale type boat, Like a Dumas Cris Craft or something. A mid-size DV hull would be suitable also if it's not speed you are after.
Just came to me.............there are several conversion kits out there in the RC Touring Car world for 4 stroke conversions, one that I remember seeing is for a .26 4 stroke. I believed it was air cooled.
I'll have a look through my mags if you want ,and see what I can come up with?
The possibilities are there