Re: which prop for evinrude 115 (1983
I ran an 18' Caravelle tri-hull with a pretty good load and did a lot of water skiing, usually with a family of 6 aboard. Had a '72 Johnson 125 which, if your engine is prop rated, and I think it is, has more hp at the prop than I had. It would run 39 alone and easily pull me on slalom, family in the boat, at 35 (tops). I remember the 35 number as I had heard that you had to get there to ski barefoot and I wanted to try that.
My prop was 17P also but was one of the first OMC SS wheels which was also cupped; much better performance than what you can get out of an alum as I had an alum (many) alums before the SS came out on the market and that was my last prop.
I think you will like it, not knowing anything else about it on your end.
HTH,
Mark