Tri-toon prop

[duckdummy1]

1) Performance issue you are trying to correct.
Maintain 27-29mph top end, but good towing and cruising ability

2) Current prop manufacturer, model, aluminum or stainless as a minimum (tested in identical weather conditions)

#1: Original E-Tec prop 13 7/8 x 13 aluminum 3-blade
WOT 6,000+ @ 23.9 mph (average load)
(this prop worked great, but no change in performance from 4,800 to 6,000+ with more throttle left in it yet. Tach only reads to 6,000. Prop is great at the dock)

#2: Viper 13 7/8 x 15 stainless 3-blade
WOT 4,900 @ 29.5mph (average load)
(great speed increase but maxed out at 4,900rpm, reverse was terrible to nonexistent)

2007 Evinrude E-Tec 115 (E115DPLSUC) on a 2007 South Bay 8522 (23.2?) tri-toon with lifting strakes, total weight unknown. Evinrude tells me 5,750 WOT is optimal on this motor. Speeds are GPS. I know there is a lot of great support info out there and thanks in advance for your time & expertise

 

[coastalrichard]

Re: Tri-toon prop

Duck...as your numbers show, you're gonna have one or the other (rpms v. mph). Is that Viper cupped?

 

[duckdummy1]

Re: Tri-toon prop

Chief Richard,

The Viper is relatively flat with little cupping. I guess my question more specifically would be what to get if I would like to operate around that 5,750 to maximize my top end yet retain performance. Evinrude tech support suggested the Viper and that was a failure because it had no reverse. Local shop suggests a SST, and I don't mind a few extra $$ to get the increased performance and durability.

 

[etracer68]

Re: Tri-toon prop

An SST is an OMC painted stainless prop. I run one on my boat, and like it. I dont know alot about Toons, but I would say the Viper is more of a speed performance prop. You may want to see if there is a prop shop around your area, that have test props.

I would have to say, you were getting alot of prop slip with the Alum prop between 4800-6000 rpm. The SST should be alot stronger, and not flex as much, at those rpms. Rev should be good too. I would try a 13 pitch in the SST. Just my .002. Maybe more Toon guys will give there expert thoughts.

 

[duckdummy1]

Re: Tri-toon prop

Has anyone found a reliable online service that will do prop exchanges for $20-30 until you find the one that works? I found one but am just wondering if it is worth it. I do not have a boat shop nearby and it would cost me $50 in gas and a day just to get to a place that will lend out a used one for trial.

 

[steelespike]

Re: Tri-toon prop

From my limited reading it appears pontoon/tritoon speeds are all over the place.
several etec tests use 15" ss props with excellent success.rpm in the 5500 5700 range.
Your speed seems good with the 15 but we need to get your rpm up.You might see if a prop shop can reduce the cup a little.
I have seen some excellent results to gain rpm that way.
4 blades are sometimes suggested for pontoons with troubles.On a pontoon they usually reduce slip,improve speed and improve handling.
Based on the rpm with your 15 it seems that you would go back to a 13" ss 4 blade prop.

 

[duckdummy1]

Re: Tri-toon prop

PropGods,

So I went with a Power Tech 14" x 12 pitch and am achieving 28mph with 5,500 RPM WOT. Everything is where I think it should be.....except I get a warning alarm from under the console after about two minutes wide open. It is corrected with a bit of trim, but when I pull a tube it is a constant alarm. None of the warning lights in the console flash for oil, water, or service, so I have no indication of what the alarm may be. My nearest Evinrude tech is an hour away. I spoke with him on the phone and the guys has no customer service skills and appears quite annoyed when I call, so this puts me at my next tech an hour and a half away. Any thoughts?