where do i find info / groups that build rc boats with 18 to 38 cc string trimmer engines, like my 50 in hydro?

my 2nd rc boat is a 50 in pickle fork hydroplane (mid 80's miss circus circus), wooden, scratch built boat. built out of 1/4 and 1/8 in plywood. this is a project that i started about a Year ago. now I'm redesigning it a lot. i have a 28 cc engine for it. its built from plans bought on eBay. i enlarged it to 50 in at the local copy shop (Kinko's). I'm looking for drive shaft / prop info so i can plan the final motor mounts, drive line, prop and rudder locations. thanks

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