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Piranha Propeller Test

Posted: Wed Sep 03, 2014 4:03 pm
by NCBOATER
Well, I thought I would give the Piranha Propeller a try on my heavy toon, since the reviews were mixed. I tried a 14.5"X15 pitch and 14.5"X13 pitch on my Yamaha F150. My stock prop is a Yamaha SS Reliance 14.5"X15 pitch. I tried the 15 pitch blades first on the Piranha prop, and I could only turn 4700 rpms and it was slow coming out of the hole. I tried the 13 pitch Piranha blades and they could only turn 4900 rpms. I was also using the new hydro bite blades the haves the raised ribs on the prop face. Both pitches also dropped my trolling speed to low at 1.8 mph GPS. I have to troll between 2.5 and 2.8 for Striper fishing. I like the concept and the design of the Piranha propellers, but they would not work on my 4500 lb toon. I think they would work great on lighter and lower horsepower applications, but for me, sadly they did not work. My toon is an Xcursion X23RFC powered by a Yammy F150. Twin tube hull at the moment, with no strakes. Just thought I would pass along my test results. I am returning the prop to Piranha for a refund less shipping.

Re: Piranha Propeller Test

Posted: Thu Sep 04, 2014 5:03 am
by rockhound
i am currently running a 13.8x11 pirahna on my 24 footer with the 3.0 merc i/o. i am happy with the prop for the most part. i went with the prop mainly due to the fact that we were having trouble getting the rig set up properly. the rig came with a badly damaged prop and mercury's prop chart gave us a totally useless suggested prop. the 11 inch pitch finally let the i/o get into the proper wot at 4800-4900 rpms.

the hole shot is pretty good, i feel i could pull up a skier with no issues, i have not tried it as the kiddos usually ride the big mable. we pull the big tube with no issues with three kids on her.

issues: the little fins they add for "bite" have begun to tear off just from normal use.

I have plans for the off-season to change the entire configuration of the boat so we will be looking at different props again. i will use the piranha hub long enough to find the right pitch for the new motor and then purchase a nicer prop for a daily use keeping the piranha for a spare. if you dont have access to loaner props for setting up your boat or have a smaller craft the piranha is a nice option as they will send you blades to try. i could continue to use the piranha on my current setup, but i do feel it is slipping more than a steel or alum. prop would,

Re: Piranha Propeller Test

Posted: Thu Sep 04, 2014 5:47 am
by TDJ2591
My new to me (used) boat came with a 15-15 Piranah. Ran 25 mph gps but only 5000 rpm. Switched to a 14.25-13 and speed picked up to 27 but RPMs dropped to 4500-4800 WOT. Tried an 11 pitch (big ear blades) but son said it was really noisy, much slower and used a lot more gas. So, back to the 13. It has plenty of torque and reasonable speed, but the low RPMs concerns me. I'm wondering if the tach could be off. I just tightened all the tach nuts and will see if that changes anything.

Would love to try stainless steel in 13 and 15 pitch, but no where to get loaner props around here.

The Piranha folks are great to talk with and know their stuff. Laura Griffiths and Mike were both very helpful and knowledgeable. They will gladly swap out blades to help you get the right one. You pay shipping. The Piranha a good concept and I believe the props are well made.

Re: Piranha Propeller Test

Posted: Thu Sep 04, 2014 5:48 am
by TDJ2591
My new to me (used) boat came with a 15-15 Piranah. Ran 25 mph gps but only 5000 rpm. Switched to a 14.25-13 and speed picked up to 27 but RPMs dropped to 4500-4800 WOT. Tried an 11 pitch (big ear blades) but son said it was really noisy, much slower and used a lot more gas. So, back to the 13. It has plenty of torque and reasonable speed, but the low RPMs concerns me. I'm wondering if the tach could be off. I just tightened all the tach nuts and will see if that changes anything.

Would love to try stainless steel in 13 and 15 pitch, but no where to get loaner props around here.

The Piranha folks are great to talk with and know their stuff. Laura Griffiths and Mike were both very helpful and knowledgeable. They will gladly swap out blades to help you get the right one. You pay shipping. The Piranha a good concept and I believe the props are well made.

Re: Piranha Propeller Test

Posted: Sun Sep 07, 2014 8:55 am
by rockhound
Your tach is off, smaller prop lower pitch and a faster boat, you have to be spinning faster,

Re: Piranha Propeller Test

Posted: Sat Aug 08, 2015 7:00 pm
by TDJ2591
Finally replaced the Piranah 14.25x13 composition prop with a Honda (Solas) 15-5/8x13 SS. The SS is designed for pontoons and is the model recommended by Honda for my setup. I'm now running around 5,500 rpm with a top speed of 27 (gps). So, WOT speed is the same 27mph as the Piranah but RPMs are where I believe (from this forum) they should be.

Interestingly, the Piranah ran 27 mph (gps) speed at 4800 rpm. At 4,800 rpm on the new SS prop I'm only running at 20 mph. Which do you guys think would burn more fuel at WOT, the old prop at 4,800 rpm or the new SS one at 5,500 rpm, both producing the same speed?

Re: Piranha Propeller Test

Posted: Sun Aug 09, 2015 6:05 am
by rancherlee
Honestly the fuel burn should be pretty close but would probably be a touch better running WOT@4800, BUT 4800rpm isn't good for the engine or all around performance. 5500rpm is a pretty good number for the large displacement Honda 135hp engine and is right in the middle of the recommended RPM range. 5700-5800 would be better but I wouldn't toss money at chasing those numbers as the BF135 had a pretty wide HP window unlike my DF140 which needs to turn 6000rpm+ to hit the rated 140hp.