[Alaninga]

I've researced composite props and decided to try this one. Got a good deal accidently as I 'googled' the prop name and found a new in box one for $60 on ebay [half price].
I've got the prop designed for my motor/boat combo, but comparing it to the aluminum stock prop [same pitch] I see the new composite has a bit less blade area on each blade [both 3 blade props/same diameter]. I've not yet tried the new Piranha on water yet but will soon.

What do you think or guess will be different in running characteristics with less blade area? I'm running the Merc 40 4 stroke shown in my avitar.

http://www.piranhapropellers.com/

 

[DuckNut]

My buddies use them in MI running rivers with rocks and although I do not have a tremendous amount of time with them they have used them for years and I can't tell any discernable difference.

 

[Alaninga]

My aluminum prop is like brand new [I've owned boats all my life, Dad's included]. However it will become by 'spare prop' even though I could replace blades on this Piranha prop easily. I do like how Piranha will swap blades for different pitch if you're careful to NOT scratch yours that you turn in for swap!
I'm very anxious to try this Piranha prop!

 

[deerfly]

After ruining a long weekend deep down in ENP last Sep by bending my prop shaft and destroying my prop after hitting some hard bottom I came across these piranha props and decided to give them a try. I got a deal too, I think it was like $85 with 2 extra blades all brand new. Been running it on my Panga 18 50hp Yami since about Feb this year and couldn't be happier. I really can't tell much difference in performance over the aluminum, but the leading edge on the composite is getting dinged and frayed a bit more than I think the aluminum would have under the same circumstances. I have hit some junk a time or two but not enough to throw any blades yet. So I can't say whether it will spare me a bent prop shaft or not on another hard impact, but that's what I'm hoping for. I regularly run a rocky gauntlet around the Homosassa area and it's holding up better than I expected for sure though. The spare blades stow easily too. Right now I think these are as good as an alternative to aluminum as anything and if they end up sparing you from lower unit damage then they are the chit. 

 

[Alaninga]

A couple of advertised advantages that DO sound logical are: lighter prop reduces 'gear clunk' when changing from neutral to 'in gear'. OK, I'll like that. Also as you said the prop is the 'sacrificial' part that breaks hopefully before you chomp the prop shaft or anything in the bullet case.
One thing I wonder is, IF the prop tosses all three of the blades on a hard hit, does the motor have a rev limiter? If your hand is not on the throttle [mine is always] could you blow the motor by letting it over rev with no blades to give resistance?
Just a thought.
Also, I've looked at the blades a bit closer and it does not appear that they have as much 'cup' as the factory aluminum prop. I think I can tell any difference in running because I can 'induce' cavitation with tilt while running. The cupped aluminum would run surfaced and bleed off air easily. I'm thinking the Piranha might not do as well. In fact I think I'll send an email to Piranha Propellers asking about wether they have some blades with differing amounts of 'cup' in them.
My researching of props in general was because I needed a second prop for 'backup'....and got into the composites. There are some interesting web sites when you search composite propellers. I had just about decided against composite when I found Piranha Propellers and wanted to try them. It's on my boat, but I've yet to get it in the water! I'll report back when I do.

 

[noeettica]

I think the performance trade off is worth it on "bad" waterways ...