Re: Trouble turning...
Cupped props help to grab water when air wants in. I don't know what the gear case diameter has to do with it, but that's just it, I don't know. My first gut reaction is obviously why?
Also as stated, engine too high on transom, or trim too far out will both increase the ability of air to enter the slipstream and cause ventilation problems.....but that's where the cupped prop came into existence.......high performance boaters that wanted to run their mils partially out of the water minimizing drag and increasing mph while still grabbing water only.
My avatar is a picture of my boat at 50 with a 90 hp. I like to play during my fishing trips and one of the things I do to play is to coast into a turn at about 30-35 and do a hard turn and halfway through the turn, firewall it. With the trim all the way out, when I smack it, it just screams; rpm's go up to 6 or 6.2, obviously sucking some air. When I complete the turn, sometimes I notice that my rpm's are lower, but still a couple hundred above normal, meaning that I am still sucking in some air. With it still at WOT, I tap the trim down a time or two and it locks back in. Once it locks back in, I push the trim back out and continue my straight line travel. But I am running a Ballistic XP SS that I drilled 1/4" vent holes into so that my hole shot would be better and still be able to run my 24P prop. The vent holes are causing the air induction once out of the hole, but that's ok....didn't have the problem till I added the holes.
Adding a few comments for those who may frown on my activities: Boat is BIA certified for 130 hp and 7 folks. I'm running a 90 with 2 folks. I boat on a 1000 acre lake belonging to a local township. You have to have a hurricane hit to have more than a 1' wave on this lake. I boat during the week and seldom are there more than half a dozen trailers at the launch. I boat away from others so as to not interfere with their fishing. We wear our life jackets at all times while on the water. I'm over 70 and in my second childhood. My last truck was a 2 door short bed Dodge Hemi in Candy Apple red and 20" chrome clad wheels and all the trimmings.....hot dog truck....it would do everything you asked of it and the higher the rpm's the more it wanted to go. You are as young as you feel and I haven't felt better in my life.
HTH,
Mark
