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How would a carbon prop affect my 350DD?


Well-known member
I have an 11-7 Star or Panacraft hull cant tell which one. It is set up driver up front and double bench in the back. Usually I only run two people. I bought and installed a brand new 350 Chevy from GM. It is not a rebuild it is brand new. I am turning a 72 x 33 I think, and I can push it up to 2500RPM's. Will switching to a synthetic prop get me more RPM's and better performance? Will it hurt my engine?
A70 or 72 carbon prop is what you need . They can be pitched to the motor to run more or less RPM.
my buddys dd350 had a wood 72/36 on a 11x7 glass boat and would not run the hill.got a 72 inch whirlwind stump puller and the boat ran the hill good.the whirl wing made a big difference.i personally per ferr sensenich q 70"
Every one will tell you that it is night and day between a wood prop and a carbon prop no matter what brand you decide to use, as long as it suits your application, but more than likely the sensenich 2 blabe Q-series 70" or72" will do nicely. You will see improved throttle response, better fuel economy and a noise reduction that is if you like the rpm you are currently running your wood prop at. I would try to get it somewhere around the 2800 mark at full throttle sitting on the trailer. it all ways good to have response more gas peddle if you need it, that is if you get one, they are adjustable, you can dial them in right where you like it.
Dagwood 0520 is right, I run a 350 dd on a 13 ft snake boat, switched over from a 72x32 wood blade to a 72 q series . the prop will spin up a lot faster , you can adjust the pitch mine is set at 2800, you will plane at a lower rpm and the fuel economy will improve, the difference for me was night and day.
Duece":2mizvze7 said:
Wouldn't the lighter prop be better on the crank as well? I always hear horror stories about direct drives coming apart b/c they weren't designed to be swing a large wooden prop.


I think a DD comes apart more so as a result of the engine not being designed to deal with the huge amounts of thrust load a propeller puts on it. A wood prop absorbs harmonic vibrations better than a hollow composite propeller and I don't think exsessive harmonic vibrations are good for an engine either much less the engine stand and rigging. I've heard several people on here comment on the amount of vibrations felt after a switch to a 2 blade hollow composite.
I am not sure about how trust loads affect on crack shafts, but I do know that in many cases were the crank shaft has failed it was because of a bad shaft itself. The way airboats use the prop to push and the the boat turns at the rear does put alot of stress right on the crank and many times engines are put together with used parts and nothing gets checked properly. Just like a buddy of mine, who built his first boat, flipped it broke the prop , then fixed his metal works bought a new prop, then lost a rudder while running hard in the water he lost control and ended up flipping his boat again prop hit the water and broke 2 blades. He tore the motor completely down rebuilt it fixed his stuff again then got it going and it did not run for 2hrs and the crank broke, he currently has given up the idea of airboating, what a pity, he never checked or changed his crank after all of the impacts.