I need to find the proper propeller for my older boat?

Need to find the proper size and pitch for my older boat. It's a 17' Renken 1977 v hull. It has a mercrusier sterndrive that the decals have disappeared over time. 302 V-8 motor. The prop has no numbers on it. I need whatever nomanclature, hub size, whatever I can get to replace the one that broke.