Ventilating a prop

[k4m]

In one of my previous posting I received a reply suggesting I ventilate my prop.<br /><br />As a "first mate" I have no idea what this means.<br /><br />Can someone define what this is, how its done? Can I do it myself or should I have a prop shop do it?<br /><br />What effect will this have on the performance of my boat & motor.<br /><br />1999 bayliner 1800 bowrider running a 115hp merc outboard 2 stroke.<br /><br />RPM's @ WOT approx. 5100<br /><br />Thanks,<br /><br />Tony

 

[rickdb1boat]

Re: Ventilating a prop

Check this link out for answers: Maybe you were taking about "Cupping" the Prop. What prop are you using now?<br /><br /> Prop

 

[Bear]

Re: Ventilating a prop

I think this is what you are looking for:<br /> http://marinemechanic.com/site/page76.html

 

[petryshyn]

Re: Ventilating a prop

K4m<br /><br />I don't believe Dhadley was suggesting you ventilate the prop, but was merely stating what could happen if you attempted to raise the motor to achieve a higher RPM using an aluminum prop. If you want to achieve the "Sweat spot" RPM, I'd take him up on the prop offer in that previous post....<br />

 

[k4m]

Re: Ventilating a prop

Thanks folks, Looks like my best option is to give Dhadley's offer some serious consideration.

 

[b.gagnon]

Re: Ventilating a prop

I would say a 17 would be just right !

 

[Hooty]

Re: Ventilating a prop

There is such a thing as ventilating a prop but I'm not sure that's the proper term. It's done by drilling holes (2 or 3) in the hub in front of the prop and letting exhaust gases out in front of the prop. It causes minor cavitation and lets the engine get up some revs,like slipping the clutch in a car.<br /><br />c/6<br /><br />Hooty

 

[Red Rider]

Re: Ventilating a prop

We have a Evenrude 90hp that has a "Raker" SS Prop that has the holes in the prop. Each hole is about ¼ inch or slightly larger in diameter. Each hole is located about ½ inch in front of each blade. The motor is on a 17 foot Dixie When the throttle is "firewalled" from idle, the boat leaps out of the water onto plane and is off like a scalded dog.