Your statement that the prop works efficiency in either rotation is correct. Now set the prop up as a right hand prop......now the shaft needs to be rotated clockwise to go into forward. I think you should be able to understand?? Putting the gear
into forward usually means you go forward and the shifting your gear
lever to the stern puts you into reverse.... it really is a pretty simple concept
. I can make a left hand prop make my boat
go forward if I run in REVERSE. Not advised!!....unless maybe the transmission can be run hard in reverse??