Prop, aluminum vs. stainless

[gobydon]

What are the pros/cons of aluminum and stainless props. I have 18 hp mercury on a 14’ aluminum flats boat. I replaced the carburetor with one for a 25 hp merc witch has given me quite a bit more power and runs a lot cleaner. Does this increase in performance mean I use a different prop? I use the boat in the shallow flats, and I am often at risk of hitting rocks. Will the aluminum prop protect the bottom end if a rock jams the prop, what I mean is will the prop, being softer material, give before the gears and shaft?

 

[kevlar3000]

Re: Prop, aluminum vs. stainless

If you are running where you are going to ding your prop I would stick with aluminum. Stainless props are great because of there strength but that can be a liability to your lower unit. I would really use stainless in situations where true performance is your goal. Be it speed or power.<br /><br />It is hard to know your prop needs as I would guess that there is no tach on board. Your prop needs are defined by where your rpm is sitting. Maybe you could find the general prop recomendation for an 18 and a 25 hp. I would assume they are gonna be real close.

 

[12Footer]

Re: Prop, aluminum vs. stainless

The increase of performance will not require a different prop if the RPMs at wide-open have not increased. I'm not a prop guru, but am safe in telling you that.<br /><br />The benifits of stainless over aluminum,is the resistance to damage from hits and such.<br />the protection inherant to any prop is provided by it's hub and other weak links (like shear-pins or keys).<br />On a low HP outboard, aluminum is best, as slight HP reduction (because of the wieght) have a better chance of being noticable. A good alternative is the "comp prop", as they are very lightwieght.