Ri237 prop options?

[Combs19 20]

Thats ridiculous lol. The factory prop should be able to handle the full amount of factory ballast and the full capacity of people that the boat can carry. My 14.5x14.25 prop came as the HA prop from the factory but my RI is also from last november.

 

They told me they started shipping all them out with them 1589 prop sometime after the 1st of the year

 

Then the H6 RI's should be able to run them as well as long as it the right pitch. More factory R&D needs to be done on this.

 

I hear you on this one! They told me there is another prop study right now going on and should hear something this week or next but if they still have the same thought of not filling up the ballast and people at the same time I will have to come up with my own study!

 

 

All the 2014-2016 Nautiques that I ride behind have 17" props here in AZ from the factory so something must have changed. These RI's need to be running a 15.5" at minimum for more surface area with the weight they carry.

I'm thinking a low pitch 15" prop is the way to go at least. Should leave 1" of space from it to the bottom of the hull.

[Combs19 20]

Messed up that quote above.

[Lak3surf3r 714]

I'm thinking a low pitch 15" prop is the way to go at least. Should leave 1" of space from it to the bottom of the hull.

That should be plenty with more surface area. The 2243 15x14.25 should work fine or the OJ WakePro 848 4 Blade 15" x 14" Propeller but the 2315 15x12 I feel would be overkill and keep the rpms way too high. I ran my 15 FS44 with the stock HA prop (14.5x14.25) on it for 278 hours last year and it only had 5/8" clearance. It was always overweighted with lead and ppl above stock ballast and never had any gel coat burn.

[Combs19 20]

That should be plenty with more surface area. The 2243 15x14.25 should work fine or the OJ WakePro 848 4 Blade 15" x 14" Propeller but the 2315 15x12 I feel would be overkill and keep the rpms way too high. I ran my 15 FS44 with the stock HA prop (14.5x14.25) on it for 278 hours last year and it only had 5/8" clearance. It was always overweighted with lead and ppl above stock ballast and never had any gel coat burn.

Ok that makes sense. I just got off the phone with a local prop guy and told him I was looking for a prop that could handle say 11 adults and full ballast. With him not know much about these new boats he said he wouldn't go less than 1" clearance and suggested the 2773 15" x 13" 0.105 cup or would the 2923 15.5" x 13" be even better? I'm really looking for a spare prop that I can stick on the boat mostly during holiday weekend when I'll have 10 to 12 people on the boat and still be able to fill up all the ballast and make it to surf speed. I also plan to run some lead on the days when it's just me and the wife/kids. Lak3surf3r what was your rpm at with the 1235 prop and loaded with people and lead at surf speed?

[Lak3surf3r 714]

Ok that makes sense. I just got off the phone with a local prop guy and told him I was looking for a prop that could handle say 11 adults and full ballast. With him not know much about these new boats he said he wouldn't go less than 1" clearance and suggested the 2773 15" x 13" 0.105 cup or would the 2923 15.5" x 13" be even better? I'm really looking for a spare prop that I can stick on the boat mostly during holiday weekend when I'll have 10 to 12 people on the boat and still be able to fill up all the ballast and make it to surf speed. I also plan to run some lead on the days when it's just me and the wife/kids. Lak3surf3r what was your rpm at with the 1235 prop and loaded with people and lead at surf speed?

It was about 4400-4600 rpm with full ballast, QS, 700lbs of lead (we threw my buddies 400lbs in that day just for fun to make the wave massive) and 10 ppl at 12mph. regularly its between 4000-4200 with my 300lbs of lead and 6 ppl at 11.6mph. Keep in mind that every 1" of pitch that you go down will take your rpms up by 200 and also for every 1" of diameter that you go up takes your rpms down by 200.

Edited May 9, 2016 by Lak3surf3r

[Combs19 20]

It was about 4400-4600 rpm with full ballast, QS, 700lbs of lead (we threw my buddies 400lbs in that day just for fun to make the wave massive) and 10 ppl at 12mph. regularly its between 4000-4200 with my 300lbs of lead and 6 ppl at 11.6mph. Keep in mind that every 1" of pitch that you go down will take your rpms up by 200 and also for every 1" of diameter that you go up takes your rpms down by 200.

 

Thanks a lot to think about. Leaning towards the OJ WakePro 848 4 Blade 15" x 14" Propeller now.

[Lak3surf3r 714]

Thanks a lot to think about. Leaning towards the OJ WakePro 848 4 Blade 15" x 14" Propeller now.

Thats what I will probably go with, it should be capable of handling a full load plus some and not go to low in pitch for the rpm band and fuel consumption. We surf about 8 hours per day and i go through at least a tank in that time if not more lol. Im going to call my dealer 1st and see what they have in stock that I can try out and see actual rpm and pulling difference.

[Combs19 20]

Thats what I will probably go with, it should be capable of handling a full load plus some and not go to low in pitch for the rpm band and fuel consumption. We surf about 8 hours per day and i go through at least a tank in that time if not more lol. Im going to call my dealer 1st and see what they have in stock that I can try out and see actual rpm and pulling difference.

Awesome! Keep me post on what you come up with. Need to pull the trigger on something before the long holiday weekend at the end of the month. Your right they do go through the gas. I've had some 4 hour sessions but as soon as the kids are out of schools I'll be pull for 8 hours plus I'm hoping!

[Donterry 7]

It was about 4400-4600 rpm with full ballast, QS, 700lbs of lead (we threw my buddies 400lbs in that day just for fun to make the wave massive) and 10 ppl at 12mph. regularly its between 4000-4200 with my 300lbs of lead and 6 ppl at 11.6mph. Keep in mind that every 1" of pitch that you go down will take your rpms up by 200 and also for every 1" of diameter that you go up takes your rpms down by 200.

 

From what I have been researching with prop manufacturers, the RPM's actually go down by ~400 for every 1 inch increase in diameter. You are correct with the 200 RPM change with 1 inch of pitch change. The prop shaft is spinning much slower with the new 1.72 reduction ratio.

 

When a boat designer increases the reduction ratio and slows down the prop shaft RPM's they need to increase the prop diameter to keep enough surface area to push the boat efficiently without too much slip. That's why you see 17" diameter props on the boats with a 2:1 reduction ratio. The Ri really should have a 16" prop. 15" is the correct diameter for transmissions in the 1.4-1.5 range. The 1.72 range should have a 16" prop and the 2:1 range should have a 17" prop. It's also important to keep the clearance to the boat better than 10% of the prop diameter (1.5"-1.7") to keep efficiency up and not hurt top end. The 3/4" to 1" clearance to the hull that ACME recommends is primarily to keep from burning the gelcoat.

 

It's really too bad that Fineline didn't design room for a 16" prop with proper clearance but I have a feeling that they will be correcting this in the future. I do think that a 15.5" prop could still be an interesting try especially if you believe you will have at least a 3/4" clearance.

[Combs19 20]

From what I have been researching with prop manufacturers, the RPM's actually go down by ~400 for every 1 inch increase in diameter. You are correct with the 200 RPM change with 1 inch of pitch change. The prop shaft is spinning much slower with the new 1.72 reduction ratio.

 

When a boat designer increases the reduction ratio and slows down the prop shaft RPM's they need to increase the prop diameter to keep enough surface area to push the boat efficiently without too much slip. That's why you see 17" diameter props on the boats with a 2:1 reduction ratio. The Ri really should have a 16" prop. 15" is the correct diameter for transmissions in the 1.4-1.5 range. The 1.72 range should have a 16" prop and the 2:1 range should have a 17" prop. It's also important to keep the clearance to the boat better than 10% of the prop diameter (1.5"-1.7") to keep efficiency up and not hurt top end. The 3/4" to 1" clearance to the hull that ACME recommends is primarily to keep from burning the gelcoat.

 

It's really too bad that Fineline didn't design room for a 16" prop with proper clearance but I have a feeling that they will be correcting this in the future. I do think that a 15.5" prop could still be an interesting try especially if you believe you will have at least a 3/4" clearance.

 

Thanks for the info. I talked to a couple different prop places including ACME. ACME does sell a few different 15.5" props but there's not many of them out there and little testing. I decided to order OJ wake pro 948 15" x 14" and should receive it next week. Once there's more know about the 15.5" I may test that next. I'll post up my findings once I get it installed.

[DarksideR 1,679]

So, any boat with the 1.72 gearing should have a 16"prop? I'm guessing there's more to it than that. Like overall weight. ?

[Dreamer 96]

What size shaft do the new boats run? Nautiques had to upsize theirs to 2" as some we failing due to the larger diameter props.

[Combs19 20]

What size shaft do the new boats run? Nautiques had to upsize theirs to 2" as some we failing due to the larger diameter props.

The Ri's are 1 1/8". Doing some looking around I was finding the same thing with other boat company's and some can't remember witch ones were warrantied and given the larger 1 1/4" shaft haven't heard of a 2" shaft yet.

[Dreamer 96]

My bad. Maybe it was the 1 1/8's failing so they upgraded to 1 1/4"

[DarksideR 1,679]

2" shaft!!! OMG. There's a joke there that I'm just trying ever so hard to avoid

[Donterry 7]

So, any boat with the 1.72 gearing should have a 16"prop? I'm guessing there's more to it than that. Like overall weight. ?

 

I'm sure there are a bunch of factors that can push it one way or another but from the little I've learned the major factor has to do with the how fast the prop is going to spin at max engine RPM's. And the WOT required RPM for these engine's is 5300-5500 RPM's with a reduction of 1.72 the math put's you at a starting point of 16" for the diameter and the pitch is adjusted to get the RPM's right for the other factors (weight, hp, elevation)

[Lak3surf3r 714]

 

From what I have been researching with prop manufacturers, the RPM's actually go down by ~400 for every 1 inch increase in diameter. You are correct with the 200 RPM change with 1 inch of pitch change. The prop shaft is spinning much slower with the new 1.72 reduction ratio.

 

When a boat designer increases the reduction ratio and slows down the prop shaft RPM's they need to increase the prop diameter to keep enough surface area to push the boat efficiently without too much slip. That's why you see 17" diameter props on the boats with a 2:1 reduction ratio. The Ri really should have a 16" prop. 15" is the correct diameter for transmissions in the 1.4-1.5 range. The 1.72 range should have a 16" prop and the 2:1 range should have a 17" prop. It's also important to keep the clearance to the boat better than 10% of the prop diameter (1.5"-1.7") to keep efficiency up and not hurt top end. The 3/4" to 1" clearance to the hull that ACME recommends is primarily to keep from burning the gelcoat.

 

It's really too bad that Fineline didn't design room for a 16" prop with proper clearance but I have a feeling that they will be correcting this in the future. I do think that a 15.5" prop could still be an interesting try especially if you believe you will have at least a 3/4" clearance.

Perfect because a reduction in rpms is needed. I just had a birdie tell me that a larger prop diameter will be going on the 2017s as well.

[Donterry 7]

That's funny, I was sure that they were going to go to a larger prop I just wasn't sure how quickly they would get it together. Unfortunately I'm about to pull the trigger on a Ri237 this week. It's killing me to know that they are probably going to make a change for the better in a few months.

 

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[Donterry 7]

Also the dealer had a few Ri237's down at Powell this week and said they were running the Acme 2277 15x15.75 prop and it was performing really well.

[Lak3surf3r 714]

Also the dealer had a few Ri237's down at Powell this week and said they were running the Acme 2277 15x15.75 prop and it was performing really well.

Exactly where my birdy came from