Plastic ring on stock aluminum OMC props?

[Johny25]

I was curious if anyone know what the plastic ring on the end of OMC props is for? I am sure other brands have them also but I have never seem them on a stainless prop or high quality aluminum props?

To me it doesn't seem to have a purpose. Just looks like extra resistance and drag going through the water. Before I go busting mine off maybe someone has input on whether it actually has a purpose. Here is a pic of what I am talking about

 

[sschefer]

Re: Plastic ring on stock aluminum OMC props?

Looks like a blow-out ring to me. It helps to keep clean up the water flow into the prop, (rough description).

 

[Johny25]

Re: Plastic ring on stock aluminum OMC props?

The ring is behind the blades. The pic is showing the back of the prop where the castle nut and cotter pin goes. So I don't see how this would help with blowout?

 

[BaileysBoat]

Re: Plastic ring on stock aluminum OMC props?

That is an exhaust diffuser ring. It prevents exhaust from causing cavitation on hole shot.

 

[Johny25]

Re: Plastic ring on stock aluminum OMC props?

Wonder why stainless props don't have them? Or even higher end aluminum props?

 

[Part-time]

Re: Plastic ring on stock aluminum OMC props?

Wonder why stainless props don't have them? Or even higher end aluminum props?

The edge will be flared out instead.