So the home-made mud motor I picked up doesn't have a cav plate. Yesterday was my first time testing it out, and for it to not cavitate I had to BURY that thing in the water. The square frame also seemed like it might be helping the prop cavitate by giving a funnel for air to get down there. At any sort of respectable speed (for a 9hp long tail on a 14ft semi-V hull) it was a chore to keep it deep enough to keep speed. I was going almost as fast at half throttle because the prop wasn't pushing as much air.
Would adding a cavitation plate make a world of difference, or does this sound like design flaw so I should look into a different frame or a whole new motor?
Side note, how easy is it to shear the shear pin? Because it broke on me last night trying to go through a little section of cat tails... as a storm was rolling in... and I didn't have a hammer and punch to get the old pin out... and the 9.9 'rude that I brought along just in case wouldn't start either. I got wet, but at least the lightning stayed in the clouds
