Prop test data

Potomacbassin’

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Yep - default position, LU is lowest in the water. I’m going to move mine to #2 or second lowest to pick up some speed and efficiency.


I think your RPMs are ok - but you can pitch or diameter down to get some additional RPM but it also depends on what Merc says your optimal range is. At least for Yamaha, the recommended diameter for their inline 200 is sub-15, but again probably different with your Merc. Maybe try a 14.5 diameter?
 

Potomacbassin’

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One more thought - see if there are any performance bulletins for Benningtons with that motor and see what the prop is. If no Benny, then check out other makes - a tritoon is tritoon, so the performance should be somewhat similar, at least ballpark.
 

Bob V

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Called the dealer told them were they put the motor in which hole, they said its's were it should be, they said to bring in the boat they will change the prop out,, They also said to change the low pressure fuel filter, but they didn't think that was the reason it's not putting out more than 5400 RPM.
 

Walter Kurtz

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I have a 2018 23SSXP with a 200 Verado, The best I can get wot, is 39 mph @ 5500 rpm,, with 2 ppl and half tank of fuel, I have a SS 15x15p prop, which the dealer put on,, I really think this boat should go faster,, I need help
I think I read the ESP gets up on plane faster, turns better and drafts less, but is a little slower on top speed vs the SPS+ due to weight and larger “pad” at WOT. I could be dreaming that as well.

I think a 17 in general will have a 1/4 or 1/2 less diameter than the 15 so it should have better top end at the sacrifice of holeshot and time to plane. Since we don’t do water sports I’m leaning towards top end and cruise efficiency. I know the 19 won’t give me that but worth testing so I know what the upper limit is. Will likely end up with a 18p or try one of the Merc props.
I’m definitely leaning towards the 17P to get me started. Motor mounting height is my next bit of research. Have about 10 days before the boat is shipped so have a little time to figure out which holes to use for motor height. It’s Interesting when you say pad, I’m guessing you mean the flat area underneath the middle toon created by the elliptical shape? I believe any flat area on a toon tends to act more like a strake in itself, in-turn adds a little more buoyancy & quicker to plane with added top-end. In my experience it’s a slightly harder ride vs the smaller round toon but if it’s speed you’re looking for, that elliptical shape should help not hurt. But as you said the weight of a heavier elliptical on the other hand will slow it down. Does the extra weight negate any gains from the pad (once on plane)? Mmm thats a crazy calculation I’m staying away lol.
If the elliptical toon that Bennington is adding to my 23SX Premium is truly less beefier than the 300HP and above models (G,R etc), then I’m hoping there’ll be a little more added speed from additional ‘pad’ vs loss due to weight. I can only hope at this point, and will have to report back with some numbers. Surprised though that nobody else has mentioned in other threads about 2 diff ESP hull options. Maybe the beefier ESP only applies to the rear part of the toon for added motor support/strength and larger fuel tank?
 

PartyBarge

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Updated slip chart, not sure if it looks right but I checked it against the Merc online calculator.

Any takeaways?



For me it would seem the current prop is horribly efficient up to 5000rpm. The 15.75 x 15 gets down into the 20% range at 2500 rpm which is where it appears to get up on plane.

View attachment 27365
OK, that's a lot to unpack, fortunately you are the type that likes to tinker. I have several comments that maybe won't be in the best of order.

Now that you are (correctly) focusing on the saltwater-series props, forget about your old prop data. The definitive document is the Yamaha Performance Bulletin. No way is some online prop selector going to give you info like that. Generally, those bulletins are gold as the combinations are not happenstance. From what I've seen and used, Yamaha only publishes about the best anyone can expect from non-custom products. Your current task (should you chose to accept it) is to make what should be a small pitch adjustment (if any) from the test boat to yours. But first consider this: on a pontoon similar to yours that 15p held your motor to 5900 RPM WOT (if memory serves). Ponder that for a moment.

No more than a pitch correction of 1 or 2 inches seems reasonable. I think you correctly speculate that a saltwater 19p may be too much (put the new prop next to your old one, expect an eyeopener). However since you are a professed tinkerer, here's a plan that MAY help. Raise the motor incrementally. With that and as the pontoon lifts with speed, you MIGHT hit a point where induced prop ventilation allows you to pull a 19p into the upper part of the desired RPM band without unloading or using some wildass trim (where you want to be, right?). Operating that way may cause other problems, but we'er only tinkering...

BTW: consider another general reference point: IF some free spirit were to find a way to hang an additional 250 HP motor on the test boat, ball park props would be ~4" "taller". Of course the resulting new speed regime might call for something other than the saltwater-series prop (Reliance?).

OK, that said, indulge me for a moment. You clearly like and value mathematical analysis...me too. However, keep in mind that mathematics are merely descriptive. Mathematics do not prove anything. Mathematics do not explain anything. That's a tough pill to swallow for some people, but if problem solving includes that understanding the results will be better. "Ground-Truthing" through actual application/observation is the path to nirvana, thus the value of reliable performance bulletins. Otherwise it's easy to make mathematical projections that would have an ancient alien theorist blushing. Yes, mathematics is the language of science. However, just like any other language, sometimes what is said is gibberish.
 

Potomacbassin’

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I’m definitely leaning towards the 17P to get me started. Motor mounting height is my next bit of research. Have about 10 days before the boat is shipped so have a little time to figure out which holes to use for motor height. It’s Interesting when you say pad, I’m guessing you mean the flat area underneath the middle toon created by the elliptical shape? I believe any flat area on a toon tends to act more like a strake in itself, in-turn adds a little more buoyancy & quicker to plane with added top-end. In my experience it’s a slightly harder ride vs the smaller round toon but if it’s speed you’re looking for, that elliptical shape should help not hurt. But as you said the weight of a heavier elliptical on the other hand will slow it down. Does the extra weight negate any gains from the pad (once on plane)? Mmm thats a crazy calculation I’m staying away lol.
If the elliptical toon that Bennington is adding to my 23SX Premium is truly less beefier than the 300HP and above models (G,R etc), then I’m hoping there’ll be a little more added speed from additional ‘pad’ vs loss due to weight. I can only hope at this point, and will have to report back with some numbers. Surprised though that nobody else has mentioned in other threads about 2 diff ESP hull options. Maybe the beefier ESP only applies to the rear part of the toon for added motor support/strength and larger fuel tank?
Correct on pad being flat area. But speed and efficiency are related to the size of the wetted area while running, so above planing speed the less surface area the better. I believe that was one of the main design intents of stepped hulls, to reduce the pad area. I do agree time to plane will be quicker with the ESP, and in that sense the larger wetted surface benefits here. But once you have realized that benefit, the extra drag starts working against the hull.
With respect to stability, I would guess the ESP is also superior to the SPS at all speeds. In general the ESP is probably the preferred option for most applications, and IF it does give up a little to the SPS in other areas, probably de minimus.
 

Potomacbassin’

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OK, that's a lot to unpack, fortunately you are the type that likes to tinker. I have several comments that maybe won't be in the best of order.

Now that you are (correctly) focusing on the saltwater-series props, forget about your old prop data. The definitive document is the Yamaha Performance Bulletin. No way is some online prop selector going to give you info like that. Generally, those bulletins are gold as the combinations are not happenstance. From what I've seen and used, Yamaha only publishes about the best anyone can expect from non-custom products. Your current task (should you chose to accept it) is to make what should be a small pitch adjustment (if any) from the test boat to yours. But first consider this: on a pontoon similar to yours that 15p held your motor to 5900 RPM WOT (if memory serves). Ponder that for a moment.

No more than a pitch correction of 1 or 2 inches seems reasonable. I think you correctly speculate that a saltwater 19p may be too much (put the new prop next to your old one, expect an eyeopener). However since you are a professed tinkerer, here's a plan that MAY help. Raise the motor incrementally. With that and as the pontoon lifts with speed, you MIGHT hit a point where induced prop ventilation allows you to pull a 19p into the upper part of the desired RPM band without unloading or using some wildass trim (where you want to be, right?). Operating that way may cause other problems, but we'er only tinkering...

BTW: consider another general reference point: IF some free spirit were to find a way to hang an additional 250 HP motor on the test boat, ball park props would be ~4" "taller". Of course the resulting new speed regime might call for something other than the saltwater-series prop (Reliance?).

OK, that said, indulge me for a moment. You clearly like and value mathematical analysis...me too. However, keep in mind that mathematics are merely descriptive. Mathematics do not prove anything. Mathematics do not explain anything. That's a tough pill to swallow for some people, but if problem solving includes that understanding the results will be better. "Ground-Truthing" through actual application/observation is the path to nirvana, thus the value of reliable performance bulletins. Otherwise it's easy to make mathematical projections that would have an ancient alien theorist blushing. Yes, mathematics is the language of science. However, just like any other language, sometimes what is said is gibberish.
I tinker because I’m not smart enough to figure out the science of it - tinkering is probably the lowest form of problem solving!

Great comments PB - I agree with many of your points. But a few other things to consider:

1) the test boat is roughly 250 lbs heavier than mine (Q ESP vs SX SPS)

2) did the test boat have the wave shield? Maybe not, mine does have the full shield including bow

3) on my binnacle, assuming 90 available degrees of articulation from N to WOT, I hit the rev limiter 5-8 degrees short of the stop. According to the Yamaha tech at the dealer, this indicates to him the motor can handle way more pitch. Is 19 out of the realm of possibilities?

I still agree with you that 19p is likely going to be the wrong prop, my guess in addition to the 2 extra inches on pitch and extra 1” on diameter my RPM will drop like a stone. But what is available to me right now is the 19 (dealer has on the shelf) so why not try it and work incrementally backwards instead of incrementally up? I think I’ll arrive at the optimal solution in as many steps, at worst a little more. But I’ll forever know that the hull/motor can’t take a 19 - no more day dreams of “what if”.

One last comment on the performance bulletin - I agree the prop is likely the best one, but for what? Top speed? Fuel efficiency? Time to plane? I would think since most pontooners bought these to be Swiss army boats, Yamaha would select the best all-around prop for the bulletin. But I don’t have any intents, at least for the foreseeable future, to tow tubes or skiers, so it’s possible a different prop would fit my boating objectives better.

Only one way to find out - the tinker train continues!
 

PartyBarge

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Ahhh....I did not get that the 19p prop is going to be a loaner that you can easily exchange and is the only one available close to what you want to try.

Also need to clear up something else. I didn't notice if you ever linked the Performance Bulletin you referenced. Below is the one I am using...note there is another similar test combination with a heavier pontoon, but same motor and prop (it made a bit less speed @ 6000 RPM). The reason for wanting to clear that up is that the calculated slip numbers I get for the test combo are significantly apart from yours. Try running those again (brace yourself for an eyeopener). Do you have the same gear ratio as the test motor (1.75? some motors, typically VMAX have a 2:1)?


I going to venture a guess that you have not run a prop with very low slip....yet. I'm also going to guess that, as of the writing of your last note, you don't have the 19p Saltwater prop in-hand yet. If it's anything like saltwater props I have seen, that will be an eyeopener too (get a load of that blade area). For heavy, moderate speed boats, common freshwater props get relegated to the toy box when a working-class saltwater prop shows up. Expect the right saltwater prop to be very good for acceleration and speed with efficiency at least as good as any other type.

Seems to me the 19p is going to be frustrating because it's step up in pitch of ~27% from the test combo and is likely to hold your motor below it's rated max-HP RPM of 5500. You might squeeze out the speed you have now (not sure about that), but expect sluggish accel. (The other side of that coin is that your current prop allows RPM well above max-HP RPM, so best HP is not available for top speed.) Anyway, your speculation that a 17p Saltwater may work is good. IF your pontoon has significantly less drag than the test boat, either a 16p or 17p MAY put 50 MPH within reach and a pontoon with better manners than you have now.
 
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Potomacbassin’

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Correct - prop has not been installed yet, dealer is backed up on work orders. Hope to get it installed this weekend and test it out - will report back findings. Thanks for comments and thoughts PartyB!
 

Walter Kurtz

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Potomacbassin
Does your dealer have your prop in stock? My dealer just told me he’s waiting on Merc & Yamaha props. Apparently all on back order & are at-least 2 weeks behind schedule to date. My boat was delivered a few days ago and still no 15x15 or 15x16/17/18 Enertias. The only one they have for me this upcoming week if I don’t want to wait is a 16x17.
 

Potomacbassin’

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Hey Walter - the SWS 15 X 18 I wanted was back ordered for sure, but dealer said they had a 15 x 19 on the shelf so we’re going to give that a go. So yes, confirming dealer said Yamaha was way behind on props. Not sure about Mercury but given the recent sales boom in boats everything boat-related is probably way behind. I would like to also try an Enertia prop. I went to West Marine a few weeks ago and it looked like a bankruptcy sale was going on.
 

Potomacbassin’

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So I went out this morning for an early fishing trip with the kids and two surprises waited for me - first, the dealer had put the 19p prop on! I was completely pumped until I went to put the key in the ignition and.... surprise #2 there was no ignition. Apparently instead of calling me and having me drop off the key, they took the ignition apart to Hotwire it and never put it back together. So the next 20 minutes were spent figuring out how to get it reassembled. I was just happy to have the new prop so no big deal.

Initial impressions were YES! This thing is so much more efficient at low and mid RPMs than the Reliance. And the amount of bite (I assume a more aggressive cup) is much more substantial, almost like having real winter tires in snow instead of summer tires. The wind kicked up on the river and we hit some 2-3’s and the prop just chewed them up and spit them out. Almost like having 4WD out there.

Now the not so great, engine RPM expectedly fell at WOT down to 5300. Speed was similar at 46. Didnt datalog as I didn’t have my laptop and was on a time constraint.
Now I can confirm the upper limit of this configuration and start working backwards. The 18p probably still be too much pitch, so thinking the 15.5 x 17 might be the ticket.
 

Vikingstaff

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So I went out this morning for an early fishing trip with the kids and two surprises waited for me - first, the dealer had put the 19p prop on! I was completely pumped until I went to put the key in the ignition and.... surprise #2 there was no ignition. Apparently instead of calling me and having me drop off the key, they took the ignition apart to Hotwire it and never put it back together. So the next 20 minutes were spent figuring out how to get it reassembled. I was just happy to have the new prop so no big deal.

Initial impressions were YES! This thing is so much more efficient at low and mid RPMs than the Reliance. And the amount of bite (I assume a more aggressive cup) is much more substantial, almost like having real winter tires in snow instead of summer tires. The wind kicked up on the river and we hit some 2-3’s and the prop just chewed them up and spit them out. Almost like having 4WD out there.

Now the not so great, engine RPM expectedly fell at WOT down to 5300. Speed was similar at 46. Didnt datalog as I didn’t have my laptop and was on a time constraint.
Now I can confirm the upper limit of this configuration and start working backwards. The 18p probably still be too much pitch, so thinking the 15.5 x 17 might be the ticket.
Based on what you got with the 19p, I am inclined to agree with the 17p. Cannot believe they overlooked putting the ignition back together. Not funny in the moment, but will be funny over time.

Good luck with your testing!
 

Vikingstaff

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Part of their new “push button” ignition system like cars these days. :oops::D:rolleyes:
 

PRaudio

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I know this is a bit apples-oranges, but I have a 23RFBA with ESP/300 Yamaha mounted in the top hole and running a SWS2 15.5x17. My max RPM lightly loaded is 5800. At the 20 hour service I asked [and was declined] if they would swap out the prop for a SWS2 15.25x16 given that is what Bennington recommends for my build. The Yamaha prop selector spec'd either the SWS2 15.25x16 or 15.5x17, so I guess I'm good (though they don't ask for current prop diameter or model when gathering data).

That said, appears to me the SWS2 15.5x17 might be a good match for your configuration unless you often run heavy. Have you asked Bennington for their recommendation for your HID?
 

Potomacbassin’

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Thanks PR - great thoughts and confirms for me the 17 is probably going to be “the one”. I’m also going to try the Enertia prop as there seems to be a lot of fanboys in the pontoon world I would guess for good reason. Only one way to know - I need to datalog the 19 first before I start swapping. Out of curiosity why did you want to try the 16? Unhappy with any aspects of the 17? Not enough holeshot or just thinking fully loaded you might drop out of optimum RPM?

I didn’t have any direct access to Bennington during the sale so no feedback from them (yet). But as luck would have it, I’m in Indiana this week and might drop by the factory if they are allowing tours again!
 

PRaudio

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I have no real issues with the 15.5x17 other than 5800 rpm lightly loaded and 5600 rpm with 50 gal fuel and three adults. Both are well within the recommended WOT rpm, but I wanted to crowd 6000 rpm lightly loaded so if I ever do have a heavier load. I believe the holeshot is great with five adults (most I've carried).

Bennington has an inquiry page at https://www.benningtonmarine.com/en-us/bennington-inquiry. They have been very responsive to all my questions. Remember to include your hull id#.
 

PartyBarge

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Initial impressions were YES! This thing is so much more efficient at low and mid RPMs than the Reliance. And the amount of bite (I assume a more aggressive cup) is much more substantial, almost like having real winter tires in snow instead of summer tires. The wind kicked up on the river and we hit some 2-3’s and the prop just chewed them up and spit them out. Almost like having 4WD out there.

Now the not so great, engine RPM expectedly fell at WOT down to 5300. Speed was similar at 46. Didnt datalog as I didn’t have my laptop and was on a time constraint.
Now I can confirm the upper limit of this configuration and start working backwards. The 18p probably still be too much pitch, so thinking the 15.5 x 17 might be the ticket.
Considering that the water conditions were not the greatest, your numbers are good. Assume you were running pretty light to do that well. You will definitely like a 17p (or 16p) better for accel and the speed should pick up a bit with either one too. Your current calc slip is ~16%. That seems a little higher than those props get on other pontoons, but the chop or motor position/trim may have caused some of that. Would love to see you make 50 MPH, but that's a tall order for 250 HP on your pontoon.......
 
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