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Thrust vs prop length


Well-known member
Ok heres the deal guys, I am currrently spinning a Sensenich 70x34 kevlar tipped stick prop on my DD SBC. I will be getting a new prop soon and I wnat some advice on the length. Lets just say for example I switched to the same prop but in a 72x34 or a 74x34, assuming I spin all the props to the same rpm, how much more thrust will I get from the longer props vs the original 70" model? When I am on plane in deepwater I can't back the rpms down below 2200 without falling off plane, I want to be able to run an plane at around 1700-1900 and I thought I might be able to with a longer prop. Or should I switch to a paddle prop instead of the stick prop all together? I don't care much about top end and a composite is out of the question for now. Thanks.
Haven't tried that yet, but when I got he boat it porposed really bad and I put some 2x3 aluminum angle (10" pieces) at the bottom of the transom on each side and bent them down a little and that cured the prorposing and now it runs real smooth at 2200 or higher, if I go down to 2100 or 2000 it will slowly just start slowing down and squatting in the back until it's not on plane any more.
I'm running a 72x 32 wood blade sensenich on a direct drive 350, hull is 13'6 cotton mouth boat planes all day long at 1600-1900 rpms depending on the wind