I am a new owner of a 1977 AMF Crestliner 15' tri-hull with a 78 Chrysler 65 hp motor. This is the first boat i have ever owned. The boat wont get out of the hole at all with 2 or more people in it. Motor seems to run strong but really bogs down and wont plane. Someone told me to change prop pitch. All I can see on my prop now are the numbers 12 and 22 in that order. I assume 12in diameter with 22in pitch. I am trying to find a prop with a lot less pitch but not sure what style will fit? I want to at least pull a tube behind my boat. Trying to figure out if what will fit this motor. I did some research and think it has a 13 spline thru exhaust type prop but would like some advice before i buy