I've seen racing boats with sharpened prop leading edges but for most normal boating I doubt there would be much to gain...I run a Stainless Steel Ballistic prop on my Yamaha 90HP and the edges are pretty darn sharp enough as they are....at least for my usage...
First off W_Guy there is nothing as a stupid question....the only question that is stupid is the one not asked.
If you are looking for performance gains by sharpening the answer is simply this....NO....you wont notice anything unless you have a fast ultra light boat setup for racing and then it is better off to let the prop experts get there hands on it. BUT it is a good practice to keep the leading edges of your prop true and in good shape. This will help to keep the prop performing as it should and also help to eliminate any further problems but keep in mind that any file work done should be VERY minimal for fear of getting one out of balance which aint good.
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Here is an example of a cleaver prop with sharp leading edges and somewhere around 15 hours running time. Even though it is stainless, note the relative blunting of the leading edge due to normal running, not damage from running through sand or mud. Note also the pattern of paint wear from ventilation/cavitation before the prop "Locks-up."
Note the damage at the tip of one blade that was incurred in shipping. UPS treated the shipping box like a football. The sharp blade punctured through the factory original shipping carton, an outer corrugated carton, AND a layer of packing in between both. You can NOT take a prop with thinned blades and sharp leading edges like this one and bang it against anything. Hit anything while running and the prop would probably be beyond repair.
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Well, Mark: I don't know if Chrysler ever had Michigan teflon coat their props but it does stand to reason that they might. When I had this prop repaired, the fellow who did the repairs remarked that where he removed the coating, the stainless underneath was not polished but rather it appeared to be sandblasted. Additionally, the parts of the blades where the coating has worn or peeled or otherwise failed to adhere, the surface looks the same. Logically, if I were going to apply a coating such as teflon or even a powder coat, I would ensure a good surface with a lot of "grab." This particular coating is glossy like powder coat but I don't think they had powder coating technology in the early 1980s (The approximate year of this prop).
These two photos hopefully show the glossiness of the coating. One also shows where an aluminum tag with "Chrysler" silkscreened in red was applied. This tag blew off the first run.
As for the leading edge, I can offer no explanation. The prop was initially sharper. It was always run in clean water and never touched bottom of any type.
This prop has probably 15 hours running time at about 3000 prop RPM and 60 MPH. I never noticed any loss of performance.
Unfortunately, My Ballistic 21 pitch runs about 600-1000 engine RPM less (I forget the exact number) and still delivers the same top speed so this prop rarely gets used anymore. Personally, I am a big fan of Ballistic props however, the lower unit thrust washer needs to be replaced with a split shaft collar on Chrysler/Force engines in order to get the necessary exhaust snout clearance to use these props.