Prop selection

[Johnny5015]

We have a 2021 23Lsrc Tritoon with the 200HP 2.8l inline 4 Yamaha engine. the current prop we are running is a 3 blade reliance series 14.5 Diameter 15 pitch that the previous owner had installed. Our top speed at about 5900 Rpm is about 36mph on a good day. We don’t do any water sports and would like to get a better top speed. Is there any recommendations as to how to achieve this? I feel as if this can definitely get faster as I see some larger boats with the same HP doing 40+ MPH. Any thoughts? Thanks!

 

[Vikingstaff]

Hmmm…You are pretty much at the top of your RPM for WOT. Reliance is a solid prop, but not the best for dialing things in for top speed at WOT. Which tritoon hull - SPS? Are your pontoons clean…like totally clean? Also, what was the load and water conditions for topping out at 36mph? Full tank of fuel and a lot of people and gear, then that’s really it. Only 1-2 people, half tank or less of fuel, and calm conditions…yup, there is more speed hidden away somewhere.

For top speed at WOT, I would recommend an SWSII or Enertia prop. I’d lean more towards a 13-14p with the inline 4 vs a 6 cylinder. The SWSII and Enertia are going to do the best job at achieving your goal. If your pontoons are dirty, even with a slight film, that will slow you down significantly. Tossing that out to highlight different possibilities.

Finally skim through the “List Your Specs Here” thread for boats and motors similar to yours. You can consider what props some of them have went with.

List Your Specs Here

 

[Johnny5015]

That RPM and MPH was with 2 people on board and a quarter tank of fuel this was a saltwater boat and the previous owner did have all three pontoons bottom painted we now use it on a lake and that isn’t needed yet the paint is still there, could that really make that huge of an impact? I’m sure I’m losing a few MPH from the bottom paint but even then, 2 people on board and less than a half tank of fuel I think I should be faster even with the paint. And yes this has the sps tritoons. And With around 5 people a cooler, and 75% fuel we are in the 26-28Mph range

 

[Jack M]

Check with Ken at propgods.com

 

[Scott1]

Vikingstaff covered most of it. Make sure you don't have water in any of your pontoons. Some people have water in toons and don't even know it, especially the middle Toon. Is 5900 your top rpm trimmed up? If so then you are around top speed with that prop.

 

[Johnny5015]

Vikingstaff covered most of it. Make sure you don't have water in any of your pontoons. Some people have water in toons and don't even know it, especially the middle Toon. Is 5900 your top rpm trimmed up? If so then you are around top speed with that prop.

Yes that’s trimmed up, is there a prop that would be better for top speed if so what prop would that be? Also how would you check for water in the toons?

 

[Scott1]

Yes that’s trimmed up, is there a prop that would be better for top speed if so what prop would that be? Also how would you check for water in the toons?

A Yamaha Saltwater Series ll or a Mercury Inertia (need a hub, no biggie). I think you should be getting more speed but I can't promise those other props will do it because you may have something else going on. If you take your boat out of the water and put on a trailer you can check to see if any water is leaking from any lower welds. You could also take an upper plug out of each toon and put a siphoning tube in with a hand pump or electric and see if you can suck anything out. Not sure if you have lower plugs in you Toons. It can get tricky because I think some Toons are chambered. Other may have better methods.

 

[Vikingstaff]

If those pontoons are not shinny clean, MPH drop off can be that much…and even much more. Many are shocked if that is their problem. Any light scum, let alone really dirty pontoons create an incredible amount of drag across the entirety of the pontoons length. Add to it that it is a tritoon and you have basically 23’ x3 of drag. It can cut MPH in half.

Also as mentioned, if any water in chambers (the SPS tritoon pontoons are 3 separate chambers) will also have a big impact. Another way to test is on a trailer have someone else pull ahead slowly and abruptly stop, while you walk beside boat and listen. IF there is any water in the pontoons you’ll hear a faint sloshing around sound.

Those two things aside, I do believe type of prop mixed with being too big of a pitch for your motor is part of the issue. But it could also be something else. Checking cleanliness of pontoons and checking for water in pontoons doesn’t cost anything, so I’d start there. If those things are ruled out, your not propped for speed with that Reliance anyway, and its probalby 1-2 pitch too much for your motor and boat. So that would be the third thing on my list. As mentioned by me and Scott already, SWSII or the Enertia prop (with hub kit) are the two that will get you to top end speed when dialed in at the right size.

Finally, the only other remaining possiblity is if your motor is mounted too low into the water. That too can cause a lot of drag, slowing a boat significantly. It really is a process of elimination. Starting with things that are free, and moving to things that cost money.

 

[Lay Lake]

How are you getting the rpm reading? If it's through a dial type guage then it could possibly be off. However, I have basically the same boat with the same motor and prop and am 38-39 mph with 2 people aboard at 5600 rpms and the motor in the lowest setting. Raising it could gain some speed but would also ventilate easier in sharp turns when I'm pulling a tube.

 

[Johnny5015]

How are you getting the rpm reading? If it's through a dial type guage then it could possibly be off. However, I have basically the same boat with the same motor and prop and am 38-39 mph with 2 people aboard at 5600 rpms and the motor in the lowest setting. Raising it could gain some speed but would also ventilate easier in sharp turns when I'm pulling a tube.

I have the simrad screen that is showing me the information seems pretty reliable but who knows, I believe the engine is up pretty high can’t remember what hole exactly

 

[Johnny5015]

If those pontoons are not shinny clean, MPH drop off can be that much…and even much more. Many are shocked if that is their problem. Any light scum, let alone really dirty pontoons create an incredible amount of drag across the entirety of the pontoons length. Add to it that it is a tritoon and you have basically 23’ x3 of drag. It can cut MPH in half.

Also as mentioned, if any water in chambers (the SPS tritoon pontoons are 3 separate chambers) will also have a big impact. Another way to test is on a trailer have someone else pull ahead slowly and abruptly stop, while you walk beside boat and listen. IF there is any water in the pontoons you’ll hear a faint sloshing around sound.

Those two things aside, I do believe type of prop mixed with being too big of a pitch for your motor is part of the issue. But it could also be something else. Checking cleanliness of pontoons and checking for water in pontoons doesn’t cost anything, so I’d start there. If those things are ruled out, your not propped for speed with that Reliance anyway, and its probalby 1-2 pitch too much for your motor and boat. So that would be the third thing on my list. As mentioned by me and Scott already, SWSII or the Enertia prop (with hub kit) are the two that will get you to top end speed when dialed in at the right size.

Finally, the only other remaining possiblity is if your motor is mounted too low into the water. That too can cause a lot of drag, slowing a boat significantly. It really is a process of elimination. Starting with things that are free, and moving to things that cost money.

Makes sense I’ll have to check for water and we don’t plan on re applying the bottom paint on the toons so I’ll probably end up getting the paint removed and go from there. If that doesn’t do the trick and there’s no water in the toons I’ll have to switch props, should I keep the same diameter at 14.5 or change that up? And as far as the pitch what would be the difference between changing it down a pitch to changing it 2 pitch down? Is there any specific benefits to both?

 

[Johnny5015]

A Yamaha Saltwater Series ll or a Mercury Inertia (need a hub, no biggie). I think you should be getting more speed but I can't promise those other props will do it because you may have something else going on. If you take your boat out of the water and put on a trailer you can check to see if any water is leaking from any lower welds. You could also take an upper plug out of each toon and put a siphoning tube in with a hand pump or electric and see if you can suck anything out. Not sure if you have lower plugs in you Toons. It can get tricky because I think some Toons are chambered. Other may have better methods.

Where can I find the upper plugs on the sps spec toons I’ll have to check that out and ruled that out first

 

[Vikingstaff]

Where can I find the upper plugs on the sps spec toons I’ll have to check that out and ruled that out first

Because your pontoons are chambered, this method really wont let you check each chamber. Do the trailer test I mentioned above. It’s the easiest way to try to determine if there is water in a pontoon. May very well not be the problem, but its free to rule out.

If there is, due to it being chambered, then you’ll need to either have a dealership sort out which chamber(s) have water and where it is leaking in (hole, weld seam, etc). They or local aluminum welder, would then need to drill and drain the chamber(s), and then weld and seal they drain hole shut.

However, I suspect your main problem is probably dirty pontoons, or perhaps non-smooth bottom paint causing excessive drag. You’d need to clean those down, maybe run hands over paint. You want them pretty much bare aluminum smooth.

 

[Vikingstaff]

Makes sense I’ll have to check for water and we don’t plan on re applying the bottom paint on the toons so I’ll probably end up getting the paint removed and go from there. If that doesn’t do the trick and there’s no water in the toons I’ll have to switch props, should I keep the same diameter at 14.5 or change that up? And as far as the pitch what would be the difference between changing it down a pitch to changing it 2 pitch down? Is there any specific benefits to both?

So, contacting Ken at Prop Gods might be helpful for you. Many here have contacted them. He is one of the best experts nationally at narrowing down recommended prop type and size for ones desired performance goal. The goals usually are either hole shot, efficient cruising or top end speed. Each of these somewhat works against the other due to how prop type, and prop diameter and pitch work to achieve each. A prop designed for quicker hole shot and thrust by nature will have lower top end speed. Conversely a prop that is designed to maximize top end speed wont maximize hole shot.

Article explaining how prop diameter and pitch work: Prop Pitch and Diameter: How they affect boat performance

Pic that explains Diameter & Pitch:


Diameter impacts thrust and torque, but creates drag.

Pitch: theoretically how far forward the boat travels in one revolution is more directly related to acceleration.

Generally each +1 in pitch increases rpm’s by 200, and each -1 in pitch decreases rpm’s by 200. Varies slightly, but its a ballpark.

Finally, different props are “cupped” differently. The cupping can impact hole shot, efficiency, WOT speed, etc….

I believe your i-4 200HP Yamahas rpm range is 5000-6000 rpms. That is where you want to remain when at WOT. Under or over is not good on your motor. For top speed you want to remain as close to 6000 as possible at WOT.

However, if you have water in pontoons, dirty, slimy or non-smooth pontoons, then those factors artificially cause your motor to work harder and increase your rpms at a given speed independently of your prop. Hence, IMHO, rule those out, and then retest your performance on the water. From there you can determine if it’s a prop issue, and what prop size and type to go with.

The props recommended so far, the SWSII and Enertia are designed and cupped to provide good acceleration arc and top end speed. They deliver nice hole shot depending on the motor, but shine in top end speed.