Prop for VF115 Sho

Kapili

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Mahalo Party Barge for your informative response. I thought spinning a 135/8 x 14 @ 6450 rpm, and 26.6 mph with a gear ratio of 2.15 where the WOT range is 5500-6300 that I would have to increase the pitch by at least 2 ", not decrease the pitch. But I guess the shape of the blades makes a huge difference. Thereʻs no calculator for that, only to spend money to try different props. Our intended use of the tritoon is mainly cruising @around at 10-15 mph, and some very occasional tubing/waterskiing.

I did run my numbers through Mercuryʻs slip calculator and got 33%. What is the acceptable slip % for my tritoon? How do you like the flow torq hub? What kind of pontoon boat do you have? The SDS prop shifting is so smooth. BTW, I remember from your previous post that you were a C-141 pilot, I flew fighters in the Hawaii Air National Guard, and retired as a captain from Aloha Airlines.

I agree with you that I should have started with a cheaper aluminum prop, but knowing that I wanted a SS prop, and after all my online research, lead me to think I could jump right to a SS prop This has been a very humbling experience for me. I still want to achieve my goal from the 4/9/21 post: "I hope to achieve about 5800-6000 rpm without trim; with trim 6100-6300rpm, and 30-35 mph. with 2-4 people and 3/4 fuel on board." I believe that this goal is firmly within reach.
 

Vikingstaff

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Yamaha's SS pontoon prop in 13p (even if it is a 3-blade) would have been a preferable starting point. If you should want to make the next attempt less expensive, try the Yamaha Talon Pontoon in 12p (3-blade aluminum) or the Quicksilver Nemesis pontoon in 13P (4-blade aluminum, Merc Spitfire twin).
Follow this advice here. Your latest prop was way too big of a pitch for that motor. I run a 16p on my 200HP (different prop all around, but still).

PartyBarge has some good suggestions here, and importantly, much better pitch sizes for that 115HP. Good luck with whatever you try next. You’ll get there.
 

Kapili

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My saga continues: Just spoke with Ken from Prop Gods, and he recommended the Talon SS Pontoon prop 14 x 12, but this prop is on back order until August, but Sim Yamaha had 1 Talon SS Pontoon 14 x 13 in stock, so I pulled the trigger. PartsVu was kind enough to give me a Return Authorization for the Talon SS4 13.25 x 16. Our intended use is mainly cruising (10-15 mph), and occasional tubing/waterskiing. Again, will update after prop arrives, and sea trial accomplished.
 

PartyBarge

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Getting your money back for the 16p prop is good news! The 13p Talon SS should not only be better, but may be about a good as there is for what you want. If any prop can put your motor/pontoon combo into the low 30's, that one should do it.

You asked several questions earlier. Maybe this will help. Calculated slip is not the be-all/end-all of performance analysis, but it is a way to see if a particular prop design is not well suited to a particular application. Saying what is too much slip can be a bit arbitrary. Most would say anything above ~25% at WOT means there is a better solution to the problem. Some, in fact, target nothing more than 10-15%, but that is a pretty high requirement for a modestly powered pontoon that is only going to run modest speeds where most people are going to run an aluminum prop anyway. As you've already figured out, switching from a high-slip prop not well matched to some use to a design tailored for a particular application is like changing the gear ratio (custom tuning the performance and getting a better hookup). Next, the Flo-Torq hubs work great. I have a couple of props that use that for our Stingray too (one of those is 23p Hi5 SS, the other a 23p Nemesis). However, the SDS hub in our 12p Talon pontoon (aluminum) is smoother and I expect the difference is even more noticeable with SS props because they weigh 2 or 3 times as much.

Yeah, active duty and reserves, I flew C-141's for ~22 years. Combined that with flying for National Airlines, Pan American and United too. Even with commuting to work by air most of the time, I've only been on fire twice....all-in-all not too bad...
 

Vikingstaff

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Kapili, I am glad you got your money back on the one prop, and a nice and specific direction to work towards based on Kens advice at Propgods. I hear such great things about him all the time on this forum.

PartyBarge, I really aprpeciate all the information and detail you provide on propping topics. Always great information and details. Also, based on that last paragraph, thank you for your service! 22 years as a military pilot is awesome.

Anyway, the comment about “I‘ve only been on fire twice...” Yikes! For us terrestrial bound humans, with safe jobs, I cannot imagine being on fire once while in the air.
 

Kapili

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Mahalo Vikingstaff for your response; and a BIG mahalo to Partybarge for your propeller wisdom (greatly appreciated!). I only been on fire once in the F-15 Eagle, it flies great on 1 engine.

The TalonSS Pontoon prop is scheduled to arrive in Hawaii on Friday 5/7. Hopefully, I can find some help (since I am fully disabled from a massive stroke in ʻ03) to mounted it on the tritoon, and give it a good sea trial.
 

Vikingstaff

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Some of my childhood dreams - going up in an F-15 Eagle, an F-14 Tomcat or Cobra & Apache attack helicopters (as well as always wanting to go up in an assortment of older WWII era planes).

I did get an opportunity to get into the Cobra once in my teens due to my uncle (career attack helicopter pilot starting in Vietnam into the early 1990’s - and eventual flight commander at a few Army airbases). I also got up in some Black Hawk Great Lakes rescue helicopters a few times with him because he piloted them for awhile following his retirement from the Army.

Of course, being on fire in an f-15 and down to one engine, not so much of interest to me. Unlike some others, I certainly don't have the right stuff for anything like that. ;)

Thank you for your service as well Kapili!
 

PartyBarge

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PartyBarge, I really aprpeciate all the information and detail you provide on propping topics. Always great information and details. Also, based on that last paragraph, thank you for your service! 22 years as a military pilot is awesome.

Anyway, the comment about “I‘ve only been on fire twice...” Yikes! For us terrestrial bound humans, with safe jobs, I cannot imagine being on fire once while in the air.
Thanks for the kind words! It was my privilege to operate some of the world's most sophisticated aircraft all over the world for multiple employers, especially PanAm. For almost fifty years, those jobs have put food on the table for the family (including retirement). All that is worth a bit of risk, although my wife might describe it differently (I operated PanAm 103, London to NYC, six days before the bomb and then after the event, but it wasn't called 103 anymore).
 
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PartyBarge

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The TalonSS Pontoon prop is scheduled to arrive in Hawaii on Friday 5/7. Hopefully, I can find some help (since I am fully disabled from a massive stroke in ʻ03) to mounted it on the tritoon, and give it a good sea trial.
Wish I could be there tomorrow to help you out! Over the years, I was a pilot on C-141's, DC-10's, B-747's and B-777's to various Hawaiian airports, but sadly haven't visited there in almost 15 years.
 

Kapili

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PartyBarge; I would be honored to have your help. I have a Hydrosteam HST that I bought from Howard Pipkorn in 1990, with a 2.4 Bridgeport Mercury racing engine with 57 hours on boat and motor. Itʻs been sitting in my yard since my stroke, because I cannot fix it (rewire) nor run it. My friend is a retired certified Mercury mechanic who can get the motor running for me. Kaneohe Bay where I live is just too small to wind the motor up, I run out of water, but I donʻt want to spend money until I can rewire/upgrade the boat.

When I mounted the motor on the boat, I didnʻt know about heat shrink connectors, so I used automotive connections for the hydraulic jack plate, trim pump, et al. Call me if you would like to chat: Marcus @(808) 342-2089. Kapili is the name of our tritoon boat (means "get together" in Hawaiian). About time for a Hawaiian vacation!
 

Kapili

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Praise the Lord! I was able to find someone to help me change the prop, here are the results for:
2021 Godfrey 2286 SBX Tritoon;
2020 VF115 SHO,
Talon SS Pontoon 14 x 13P.
Wind 20-25 mph,
3 people,
1/2 tank gas (15 gal),
With trim into the wind: 5600 rpm @27 mph(GPS),
Following sea, with trim: 5850 rpm@32mph.
Time to plane about 1.5 seconds, great hole-shot, boat will turn with no sliding/cavitation @ WOT.
The Talon Pontoon prop really bites the water, ie: I went from 33% slippage to an unbelievable 4% slippage!

Mahalo to Partybarge and Ken Reeves from PropGods for the correct advice, they recommended a Talon Pontoon Prop with a 12P, but this prop is on backorder until August, a 13P was in stock (the above tested prop). In order to obtain the best performance out of our Tritoon, I will place an order for the 12P on Monday, to get at least 6000-6300 with trim, but will confirm this with Ken Reeves before placing the order.
 
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