I think having the engine able to do 3600-3800rpm on existing prop is comforting and doesn't mean I'll run at that speed all the time or at all. Mostly I do betw 2600-3000rpm but with some white smoke (and doesn't smell or look like steam, nor do I burnt luboil). Also with max 3600rpm in gear, there is scope for me to re-pitch my prop currently 14"Dx6"P 3-Blade Campbell Sailor by an inch or two. I've an 18HP 2GM20F on a 8500lbs displ boat. Its supposed to be sufficient but at times, I've to struggle against tide and also usually last in a convoy (when no wind).
2002 Hunter 326, SV Millennium 2
1999 Macgregor 26X, SV Millennium