Slowing down my 8 hp four stroke honda
 

I have an 8 hp Honda 4 stroke that I would like to use on a 19 ft. Flat bottom displacement hull. The boat was built for sail but I'll be using it as a launch. My plan is to build a well. This was tried in the past with a similar boat with poor results because the motor has way too much thrust. The boat could just not go slow enough. It has the three blade prop that the motor came with. Is there a stock propeller that I can get that won't push the boat at hull speed at idle?