TRI TOONS, 3 OR 4 BLADE PROP TRUTH AND FACTS....

[2FORCEFULL]

I THINK I KNOW THIS FOR FACT... as I read it on the internet....heavy boats like 4 blade props and tritoons should run @ 10% slip WOT...

 

[2FORCEFULL]

so using facts...
17p 3blade, 1.85 gear, 6300 rpms,52 mph, =5% slip..

using 10% slip, 17p, 1.85 gear..6000 rpms, = only 47 mph...

 

[2FORCEFULL]

I'm gonna be doing a lot of testing on 2 different 24' pontoons... one honda, and one Evinrude.... one 2 stroke, and one 4 stroke..

but here's some info from what I've found out so far with the 27 vs 24 toons,... the honda, 5000 rpms netted 30 mph...that's 25% slip

while the Evinrude ,4000 rpms netted 30 mph....that's only 14% slip...

so what does that tell me... the 3 blade on the honda was not getting enough bite,...coach said this...the 17p is too big and it blows out before pushing the 27' toon...

so using that theory, 15p, 4000 rpms, 2.0 gear ,10% slip...only 26 mph

 

[Andy B.]

I think you buy stuff just to do testing LOL!

 

[2FORCEFULL]

also another fact....I was asked... how much difference the 1.85 vs the 2.0 is in MPH? with all things the same otherwise..4000 rpm, 17p , 14% slip, the mph is 2 mph slower... so to make up the 2 mph, you'd have to be able to spin a 18.42p prop

 

[2FORCEFULL]

so here another point,... the Evinrude is a torque monster, lets say it spins a 19 pitch prop.... the same 30 mph will be done at only 3600 rpms..... you would need a vacume gauge to measure the load on the motor...or make sure it will still spin to the max 6000 rpms....

but lets say now you went to a 4 blade 17p to bring the slip down... to 8%... the same 4000 rpms would net 32 mph...

 

[2FORCEFULL]

so here another fact, and why guys that know better have no problem calling bull shit on toon speed...17p prop, 1.85 gear 52 mph is zero slip... yeah, sure you did...but, another fact... if you over rev the motor to 6500 rpm, you can get there with 8% slip..

 

[2FORCEFULL]

but at the same time...my way of propping a boat is this,.. if you can over rev by 500 rpms... try a bigger prop... using the same numbers... a 19p prop will get you to 54 mph @ 6000 rpms...

 

[2FORCEFULL]

so my goal is this...take the 3 blade theory …. and prove it to be fact... or fiction...and my theory is this...the proper 4 blade is gonna net better performance than a 3 blade.... on a load...as in pontoon..

what I want out of my pontoons is the most I can get with what I got...I wanna cruise @ 30 mph...at a lower rpm, and still be able to go the most mph @ wot.... notice I didn't use the words fast, faster, or fastest

 

[2FORCEFULL]

So in my testing, after removing the roll bar and windshield, both toons will be pretty close in weight... the coach has a 60 gal fuel tank... so I'd have to test with the coach 3/4 tank, with the godfrey @ full...to keep it fair... but just guessing,... the other difference is the godfrey has a 27'' toon with a notched rear..that should be a faster toon ...my guess is this,..when at max performance... the Evinrude godfrey toon is gonna be 5 mph faster.... that's a lot of mph ...10% faster...

 

[2FORCEFULL]

also, gonna say this...you get a lot of bang for your buck wth the godfrey / Evinrude @ only $59,999

 

[Outdrive1]

No way does a tritoon run at 10 percent slip.


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[2FORCEFULL]

No way does a tritoon run at 10 percent slip.


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more fiction....

 

[Outdrive1]

more fiction....

And no aerodynamics


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[2FORCEFULL]

here's more facts.... the 27 coach weight is 3050 lbs... the 24' is 2800 lbs... while the 24' godfrey is only 2500,... my theory is the roll bar and windshield plus the added weight of the second helm picks up the 300 lps… or more...

 

[2FORCEFULL]

And no aerodynamics


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with the front and rear doors open , and the right angle of attack, you have a magic carpet ride

 

[2FORCEFULL]

never believe what a salesman says and you will be $$$$$$$$$$$$$$$$ ahead...

 

[Outdrive1]

with the front and rear doors open , and the right angle of attack, you have a magic carpet ride

Lol.


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[2FORCEFULL]

Evinrude makes a prop, rx4... they say it's for tri tooms….????

and question,... anyone tried a 4 blade on a toon?

 

[DRYHEAT]

You’re forgetting wave spanning ability between the two different length boats in your equation.

 

[2FORCEFULL]

You’re forgetting wave spanning ability between the two different length boats in your equation.

????? faster or slower???

 

[DRYHEAT]

????? faster or slower???

I have no idea Steve, just stirring the pot a little bit. But I do enjoy reading your comparisons.

 

[2FORCEFULL]

I have no idea Steve, just stirring the pot a little bit. But I do enjoy reading your comparisons.

gonna be interesting for sure.... getting the motors set to the right height for the props and testing 3 and 4 blades...I'm thinking the motor could be a hole higher with four blades...

 

[outboardrick]

Evinrude makes a prop, rx4... they say it's for tri tooms….????

and question,... anyone tried a 4 blade on a toon?

Steve, I've done a bunch of prop testing on similar boats. I'm like you, if my boat has the potential to go 29.5 mph then that's what I want to see! As you know, props are all different and they react differently on different boats. Basically the best set ups I've found are large diameter/blade area 3 blades such as Merc Mirage. I was VERY surprised as to how efficient a Merc High 5 was on an outboard deck boat I had. Your results may vary

 

[LHC30]

I’ll throw our 23 Bennington with a 200 Verado in the test pool.

 

[FlyByWire]

The math is over my head. Our toon hits the limiter at 55 ish with a 16. Tested with a 17 solo (sales demo) was 60 on the nose so they dropped a pitch because we would always have a few people on board.

I want to try a 17 with the family and see if it’s better, or at least gets me off the limiter.

If you have one that’ll fit a mercury 400 I’d be interested if you are going to sell it once you nail down the right one for yours.

 

[Lavey29]

While spending a grand on a new prop for 1 or 2mph in a toon doesn't appeal to me, I am curious what your water testing of different props shows. Pretty sure most of us roll with full bimini up so that has to take away from the top end also.

 

[warlock250]

gonna be interesting for sure.... getting the motors set to the right height for the props and testing 3 and 4 blades...I'm thinking the motor could be a hole higher with four blades...

Ask Scott about a the Electric Jack off plate. Lol.

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[BajaMike]

The math is over my head. Our toon hits the limiter at 55 ish with a 16. Tested with a 17 solo (sales demo) was 60 on the nose so they dropped a pitch because we would always have a few people on board.

I want to try a 17 with the family and see if it’s better, or at least gets me off the limiter.

If you have one that’ll fit a mercury 400 I’d be interested if you are going to sell it once you nail down the right one for yours.

You’re always better with a lower pitched prop. Family and friends show up. It puts way less stress on the engine and Captain.

 

[2FORCEFULL]

While spending a grand on a new prop for 1 or 2mph in a toon doesn't appeal to me, I am curious what your water testing of different props shows. Pretty sure most of us roll with full bimini up so that has to take away from the top end also.

Friday I went from winsor to the avi casino,... on the way back pretty good head wind...so I put the top down,... cruised 50 not on pin...personally I think the motor needs to come up,...and think it will do better with a 4 blade... but, everyone pretty much runs them how they came....Sues Evinrude jumps on plane....and I think it's gonna be about 5 mph or more faster than my honda….I was in havasu this morning, got the windshield off, and last night we got it switched on to the triple axel trailer,....I didn't know catus didn't do service work,... but I dropped it off anyway this morning,.. there gonna install the bimini top, and warranty the dash, the vinyl covering is coming loose... so probley won't get it back till Tuesday....then I'll go run it to get a base reading,... I have a 17p and a 19p prop to try...

 

[2FORCEFULL]

Question…. does any one know how far below the bottom of the toon the prop shaft should be????

 

[2FORCEFULL]

Ask Scott about a the Electric Jack off plate. Lol.

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how much are they???

 

[warlock250]

how much are they???

Go see Scott. Lol. It's our little mph secret and Berkshire learned that from us for the Twin engine boats[emoji6][emoji8]

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[Lavey29]

Question…. does any one know how far below the bottom of the toon the prop shaft should be????

I'll take a picture of mine tomorrow when I get into town but I know it sits pretty high with minimal draft on plane.

 

[Lavey29]

I do think I'm getting to much slip with the 17 Enertia 3 blade though. So curious how your 4 blade tests look.

 

[warlock250]

I'll take a picture of mine tomorrow when I get into town but I know it sits pretty high with minimal draft on plane.

Put a straight edge out from bottom of the Toon to drive case

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[2FORCEFULL]

Put a straight edge out from bottom of the Toon to drive case

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and where should the prop shaft be from there...I guess there is a lot of variables when it comes to toons and prop shaft heights and props... thinking all I know about boats and props is not gonna apply ...

 

[warlock250]

and where should the prop shaft be from there...I guess there is a lot of variables when it comes to toons and prop shaft heights and props... thinking all I know about boats and props is not gonna apply ...

That's the beauty of the Jack plate. You can bury the prop deep for turning (Tubing kids) and then raise it up high for better top end speeds. Now the fun begins because I haven't takin a lot of time to play with the different combinations of props and the jack plate heights for the differences in how they perform while plates down or up with different props.
So you could try out different style and pitch props to see. Usually larger diameter props work the best for Toons.
We usually see a 3 to 4 mph top speed with the Jack off Plate. [emoji12]

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[2FORCEFULL]

That's the beauty of the Jack plate. You can bury the prop deep for turning (Tubing kids) and then raise it up high for better top end speeds. Now the fun begins because I haven't takin a lot of time to play with the different combinations of props and the jack plate heights for the differences in how they perform while plates down or up with different props.
So you could try out different style and pitch props to see. Usually larger diameter props work the best for Toons.
We usually see a 3 to 4 mph top speed with the Jack off Plate. [emoji12]

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now throw the notched 27'' gt in the mix....confused here....when you first hang the motor... do you straight edge the bottom of the toon and sit the motor at a specific measurement...

 

[warlock250]

now throw the notched 27'' gt in the mix....confused here....when you first hang the motor... do you straight edge the bottom of the toon and sit the motor at a specific measurement...

For a fixed bolt on motor I never played a lot with the height with the straight edge off the bottom but I have seen when running at speed the motors seemed a little deep and could come up a hole. But if they set them up high then the people complain about blowing prop out.

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[warlock250]

Being able to control the X dimension on the fly is handy for lots of situations. It also allows you to raise it high enough that you can go into some seriously shallow water at some beaches and not have the gear case hit the sand.
Or drop it down low for Holeshot lol. Just kidding but it does make it better for whipping the kids on the tube.
I like the 10" jack Plates lots of travel.

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[2FORCEFULL]

 

[2FORCEFULL]

There are disadvantages to raising the motor. With the propeller closer to the surface it’s more likely to ventilate and slip on acceleration, making it harder for the boat to get on plane. And the trim tab above the prop may become less effective and make the boat harder to steer at speed.

But if the motor is mounted too low the anti-ventilation plate will drag in the water when the boat is on plane and can cause excessive spray around the motor and transom. Low-speed work boats pushing a heavy load, however, can benefit from having the motor mounted low and the prop deep in the water.

 

[2FORCEFULL]

There are quite a few variables in play when considering optimal engine height on the transom. A key factor is how far aft the propeller is located from the bottom of the boat. Water flowing from under the boat rises so if the prop is further away from the transom, it may be possible to mount the engine higher. All outboards are different in this regard. For example, a Mercury Verado positions the propeller about six inches further aft than a Mercury OptiMax outboard. A boat rigger’s rule of thumb is that the motor can be raised one inch for each eight to 10 inches of distance between the transom and prop. As the prop moves further aft, it’s also likely to be in cleaner, “harder” water, and be more efficient. This is one reason performance boaters use a set-back device between the boat transom and the motor bracket.

Propeller diameter also can affect the ideal engine mounting height. Switching from a small-diameter prop like a 13.5-inch Mercury Laser II to a 14.5-inch Mercury Enertia effectively lowers the swing of the prop blades by a half-inch.

 

[2FORCEFULL]

A True 20

Despite the effort to standardize transom height and motor length, there has been some “creep” by both boat and engine builders over the years. Techs I talked to say that most “L” outboards actually measure about 21 inches, which may be intended to provide a little adjustment latitude – the motor can always be moved up if it’s too long for the transom, but it can’t be moved down. This issue became apparent with the introduction a few seasons ago of the Mercury 150 FourStroke. Mercury engineers designed an all-new mid-section and mounting bracket for that motor and made it exactly 20 inches to the anti-ventilation plate, and have since done the same for its new Mercury 70/90/115 models. Last summer I had a dealer tell me a few customers were having trouble with Merc 150s blowing out the prop on hole-shot and in even moderate turns. The motor was too high but mounted as low as possible. Turns out some boat builders are letting transom height get closer to 21 inches or 26 inches.

 

[2FORCEFULL]

There also can be significant imprecision on fiberglass boats. One tech who rigs a lot of motors tells me he measures every transom, and will find up to an inch variance in transom height on different examples of the same boat model. This was exactly the problem encountered by the dealer with the unhappy Merc 150 customers, with the worst cases being on pontoon boats. Because pontoons can create a frothy stream of aerated water at the transom, the prop really needs to be set down in the water.

Greenwood says Suzuki is also moving from a “stretched” length to a “true 20” on its latest DF70A and DF90A motors, and has encountered an occasional issue with a tall transom. The solution is usually a different prop with more blade area, often a four-blade propeller.

 

[Lavey29]

I did not have a straight edge up here but measured it with tape measure. I would say the lower unit extends 21" below the bottom of the center can. It also appears that the engine is mounted in the lowest position possible on the jack plate attached to the transom. I know I really need very little positive trim at speed with the way the engine is mounted.

 

[warlock250]

Another factor that can really affect cavitation is if you have a lot of people sitting towards the front of the boat therefore lifting the stern a little higher and the prop cavitates.. Once again with the electric jack u off plate u can lower the motor. [emoji6]

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[PlanB]

Your cavitation plate should be just above the waterline when running at speed. When I bought my current toon the motor was mounted as low as possible. I raised in one hole (about an inch) and picked up 7mph. I could probably go up another inch, but the boat still turns well and top speed is about where it should be for the size of the boat and the power I have (probably leaving 2-3 mph on the table). The cav plate is also just above the waterline now when running at speed.

When I was setting up my Skater I was able to get hard numbers on motor height and setback using jack plates from guys that had already done it. With toons there is not as much info out there because most don't care much about dialing them in for ideal performance. The manager of the dealership I bought my toon from thought I am crazy for changing the motor height until I told him I gained 7mph.

A jack plate (like mentioned above) would be the easiest way to play with motor height. It might also void your warranty though. Good luck with the prop testing. I have thought about trying a 4 blade as well. I will be interested to read how the different props work for you.

 

[Lavey29]

also, gonna say this...you get a lot of bang for your buck wth the godfrey / Evinrude @ only $59,999


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2FF - Does it look odd to you that the water line appears to be around the engine cowling as you are beached there? I know the water level on my Merc is no where near the top portion engine cowling just the mid portion even idling trimmed down. Perhaps your engine is made to operate differently like a sealed unit.