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wheels

Help me pick a prop for 17 ri237

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wheels    147

So I will be ordering my new ri237 shortly. They have told me I can order it with what prop I want. With the new strut angle I have lots of options for a bigger prop which this boat definitely needs. I want to be able to get the surf rpm's down to between 3600 to 3800 if possible and have enough torque to have full ballast and people.

 

Surf prop for 2016 was 1589 14.5" x16 pitch which runs between 4200 to 4600 of what I've seen and heard but struggles with full ballast and more than 4 people.

Heard some new 2017 coming with 2277 15x15.75 haven't heard real world reports on performance and rpm?

 

I would like to run a 15.5" diameter so thinking either

2849 15.5x15.75

2847 15.5x15

 

Anyone have any insight of these or what they may do for rpm and performance? I know for every 1" in diameter you decrease 400 rpm and for every 1" drop in pitch you increase 200 rpm.

Edited by wheels

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Darkside    248

When i demoed the 17 237 it had the 14x5x16 center tank was at 75, everytging else full, i am not sure what cats, and stinger were set to but RPM was 3900. Personally i would do 17x20 if it would fit, 16x16 second choice, 15.5 x 16 third.

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wheels    147

When i demoed the 17 237 it had the 14x5x16 center tank was at 75, everytging else full, i am not sure what cats, and stinger were set to but RPM was 3900. Personally i would do 17x20 if it would fit, 16x16 second choice, 15.5 x 16 third.

As of now it is still coming with a 1 1/8 shaft so I do not want to go any bigger that 15.5". Centurion tells me they have no plan to change the diameter on the ri237. Ri257 comes with 1 1/4 shaft and 16x15 prop. Dark, did you have the bow bag full on your demo?

Edited by wheels

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Darkside    248

No bow bag was empty, it is primarily used for wakeboarding...i did not even order a bow bag on the 257. Caveate, i pulled 1000 pounds of lead out of the MXZ last night. So if i needs a touch of bow weight, i have a solution. The factory rep recommended adding a couple hundred pounds in each corner, below PNP...

Also even if i ordered PNP they made bow bag smaller, the RI do not seam to like bow weight. They made rams and center a touch bigger, but bow for 257 is 500 vs 750. They may have changed the 217/237 also i am not sure. 257 also comes with transom bag, full width behind the engine. 500 pounds there... so sink that platform!

Edited by Darkside

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Kalidgh    37

I jerked around with the prop changes and in the end I run the prop that the designers and engineers designed it from the factory with. You move away from that prop ,you will give upon thing to gain another.....and vice versa.

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wheels    147

I jerked around with the prop changes and in the end I run the prop that the designers and engineers designed it from the factory with. You move away from that prop ,you will give upon thing to gain another.....and vice versa.

Is your a 2017? What prop came on your boat?

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wheels    147

I went with the 2277. Only options from factory is 2277 or 1589. Boardco is having some 16x13 ish acme props made for them that I may change to after I have tested the 2277.

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Darkside    248

The 257 surf prop is 16x13, it seamed to work well.

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Mrdeerwood    26

Wheels. Did u get a chance to run your boat w the 2277? How was it?

 

I have been in a few 16 Ri237's. As I have said before on here it really struggled with the 14.5" 1589 with the H6 when slammed full. Glad to see they addressed the issue and made clearance for a bigger prop!

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wheels    147

No I have not had a chance to try with the 2277. I will try it fully loaded with 400lbs lead and see how it does and what rpm' s it is spinning. I want to be able to reach speed fully loaded but would also like to have the rpm under 4K. Darkside just got his 257 with h6 and he has the 16x13 and was spinning 3900 rpm. Once I have real world results and numbers I will be able to figure out what prop to change to if need be.

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Darkside    248

I am also suspecting if I run a touch of weight up front and get the bow down a bit the RPM will follow. I am going out again Saturday we will have 7 people on board so and I am going to run a touch more weight. We will see how she does.

Edited by Darkside

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nailem    29

Please post results when you have them.

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carguy79ta    66

Darkside I would say load it up full. when I tested the 16 237, I could adjust the wave to shorten it or lengthen it with the CATS

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Darkside    248

I have to play with it, there is SOO much more adjustability than I am used to.

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MistyCreek    3

We are running the 2847 on our 2016 ri237. I have No complaints of significance. We are in Utah so we run 3500 elevation when at Powell and as high as 6500 or so at the mountain lakes we visit frequently. This prop yields about 3700 rpm for surfing with the rub rail within an inch or so above the water. For cruising at Powell, 25mph is about 3500 to 3600 rpm depending on load. Pretty good overall for such a heavy boat at elevation.

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wheels    147

We are running the 2847 on our 2016 ri237. I have No complaints of significance. We are in Utah so we run 3500 elevation when at Powell and as high as 6500 or so at the mountain lakes we visit frequently. This prop yields about 3700 rpm for surfing with the rub rail within an inch or so above the water. For cruising at Powell, 25mph is about 3500 to 3600 rpm depending on load. Pretty good overall for such a heavy boat at elevation.

No prop burn on gel coat with a 15.5" diameter prop on a 16? Do you have the old shaft angle?

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MistyCreek    3

No prop burn. 143 hours of use. About half with this prop. Started with a 15", wanted as big as possible for better cruising speed and lower surf rpm. Mission accomplished. Yes, original prop angle.

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wheels    147

Awesome to hear. Where were you four months ago when I started this thread. Lol

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Fivebar2    176

I used the one that came with it, it worked pretty well

Edited by Fivebar2

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Lak3surf3r    712

No prop burn. 143 hours of use. About half with this prop. Started with a 15", wanted as big as possible for better cruising speed and lower surf rpm. Mission accomplished. Yes, original prop angle.

Thats impressive! Do you have a pic of the prop to show the clearance with that 15.5 on it?

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Darkside    248

I have the H6 and surf prop (16x13) on my 257. It handled everything we threw at it with ease! Never once did I feel a lack of power. Surf RPM 4000 regular 3800 goofy, this is likely due to different quicksurf, stinger, etc between sides. Downsides...4000 RPM at 23 Mph cruising. Top speed 33. I would be very interested in trying a 17x15 or 17x17. However this is going to be very low on my priority list.

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Lak3surf3r    712

I have the H6 and surf prop (16x13) on my 257. It handled everything we threw at it with ease! Never once did I feel a lack of power. Surf RPM 4000 regular 3800 goofy, this is likely due to different quicksurf, stinger, etc between sides. Downsides...4000 RPM at 23 Mph cruising. Top speed 33. I would be very interested in trying a 17x15 or 17x17. However this is going to be very low on my priority list.

 

Joe, make sure you have them to try before you buy 1st. By my math if you were at 4000rpms on the Port (the only) side that counts ;) and went to a 17x15 it would only lower you to 3800rpms (4000-400 for 2" of pitch + 200 for gaining 1" diameter) or for the 17x17 would put you at 3400rpms (4000-800 for 4" of pitch + 200 for gaining 1" diameter). But moving up to 17" diameter with more surface area while changing that much in pitch also increases your chances of cavitation on that heavy of a boat (15k of ballast, gas, people, and the boat weight). If I were you I would try a 16x15 or something close to that if that is an option and see if it works as that should drop you 400rpms before going up to a 17"

Edited by Lak3surf3r
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wheels    147

 

Joe, make sure you have them to try before you buy 1st. By my math if you were at 4000rpms on the Port (the only) side that counts ;) and went to a 17x15 it would only lower you to 3800rpms (4000-400 for 2" of pitch + 200 for gaining 1" diameter) or for the 17x17 would put you at 3400rpms (4000-800 for 4" of pitch + 200 for gaining 1" diameter). But moving up to 17" diameter with more surface area while changing that much in pitch also increases your chances of cavitation on that heavy of a boat (15k of ballast, gas, people, and the boat weight). If I were you I would try a 16x15 or something close to that if that is an option and see if it works as that should drop you 400rpms before going up to a 17"

Lake you have the diameter Rpm's backwards

 

For every 1" of diameter you increase you would drop 400(approximately) rpm

For every 1" of pitch you increase you would drop 200 rpm

So he would be theoretically at 3200 rpm. With the 17x15. I do not think the 17x7 would work at all with 1.72 gear ration on ri257

The non surf prop 16x15 may just be the right prop for the ri257 as long as it can get it up to surf sped with out a struggle. It would be around 3600 rpm. In 17" you would want a 17x13 or 17x14 in theory

Edited by wheels
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Lak3surf3r    712

Lake you have the diameter Rpm's backwards

 

For every 1" of diameter you increase you would drop 400(approximately) rpm

For every 1" of pitch you increase you would drop 200 rpm

So he would be theoretically at 3200 rpm. With the 17x15. I do not think the 17x7 would work at all with 1.72 gear ration on ri257

Agreed, i doubt the 17x17 would even work on that 257

 

 

"If you're changing pitch on a recreational boat, remember that each inch of pitch is worth about 200 rpm. Lowering the pitch will increase rpm and vice versa. For example, going from a 23 pitch to a 21 pitch will increase engine rpm by about 400 revolutions."

 

"Increasing pitch reduces rpm and reducing pitch increases rpm. A 1" change in pitch will usually result in a 200 RPM change in engine speed. Therefore, if your engine operates below the optimum proper rpm, you should consider a boat propeller with less pitch. If your engine over-revs, consider increasing the pitch."

 

^ That being said increasing the pitch by 2" (13" to 15") would drop it 400 and add 200rpms by adding 1" diameter (surface area)

 

 

 

 

Also Ive changed props on 2 different surf boats keeping the pitch but going up 1" in diameter and it has increased rpms by 200ish on both (possibly just because of slip and drag). For some reason its always different on different boats though lol. they only way to know for sure is to try!

 

ive tried tons of props on tons of boats and this is what ive found to be true. Just my opinion though and the numbers are estimated theoretically. I used to have a spreadsheet to calculate it but lost a backup HD and cant find it anymore :(

 

Edited by Lak3surf3r

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