Choosing a prop help.

Ladon

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May 3, 2019
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Hey Guys and Girls, I need help choosing a prop. My current prop is a 13.7/8 x19 viper. I need more hole shot so im looking at a 14x17 or 13.25 x 17 four blade. Which will be the best and still keep me in my wot rpms.
 

Ladon

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May 3, 2019
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7
Choosing right prop.

Hey Guys and Girls, I need help choosing a prop. My current prop is a 13.7/8 x19 viper. I need more hole shot so im looking at a 14x17 or 13.25 x 17 four blade. Which will be the best and still keep me in my wot rpms.
 

Starcraft5834

Lieutenant Commander
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Jun 2, 2013
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Assuming your current prop at WOT is running within your engines recommended rpm range... more hole shot will be accomplished with a 4 blade prop, what you have already stated going to (17) 4 blade would likely give u what u want, you may loose a few mph top end tho
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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read the first sticky in the prop forum and answer post the answer to all of the questions. if you dont have an answer, go get it before posting all the answers to all the questions.
 

Ladon

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May 3, 2019
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Thanks for the reply. Yes current prop is giving me the WOT rpms. Just wondering if the lower diameter prop will be any better. This props are from different manufacturers that can get close to the viper in size in a four blade.
 

jimmbo

Supreme Mariner
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May 24, 2004
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12,944
What is your engine? "current prop is giving me the WOT rpms" is very Vague. Where within the WOT range is it running?
It is difficult to make comparisons of between brands of prop, or even between different models/lines within a brand. Your are currently running a viper, which is a slightly, very slightly, tweaked version of the original OMC SS line. If you want a 4 blade with the same blade shape as the Viper, your best chance of that is from BRP.
 

Ladon

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May 3, 2019
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My boat is a 16ft Hydro sports,CC. Skiff with a 2001 70 johnson. Boat DW is 1390lbs total weight I figured 2100to 2200lbs loaded. With the 13 7/8 x 19 viper it pushes the rpm 5500 to 5700 based on trim level. Im trying to fish the flats, taking off in 2ft of water. The boat is sluggish getting on plane. Im looking at the four blade aluminum turning point props for there forgiveness if i strike under water objects. The boat is in the shop now for shaft replacement because of the viper didnt give any on striking a rock. Im thinking of raising the motor up two notches and going to try the 14x19 4 blade TP props has (I know raiseing motor up will increase the rpms as well). Im willing to give up the speed to gain plane quickness. Just didn’t know rather the 13.25 x 17 or 14x19 would be better.
 

Scott Danforth

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you are already are prop'd right for the motor WOT RPM range

if you have 3 blades now, you can drop in pitch to go to up in number blades. do not keep the same pitch when adding blades

dropping down to a 18p or 17p and going up a blade would help. however if you simply wanted a better hole shot, a vented prop would help too. many times, simply moving the beer cooler to the bow is all that is needed to get out of the hole

you are trimming all the way in for the hole-shot correct?

as for raising your motor, take a picture of the boat and motor from the side (and stand back about 10' farther than you think). make sure the motor is down and the anti-vent plate is even with the keel. if the AV plate is even with to about 1" above, its about perfect for height and raising it will only cause venting. raising the motor up only raises RPM's if your venting (prop blow out) or plowing because you are too deep.
 

Ladon

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May 3, 2019
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So the 13.25 x 17 will be a better choice? I was afraid of the diameter drop would cause more prop slip? I wished they made 14x17.
 

Scott Danforth

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the prop diameter doent affect it as much as blade profile or pitch. however if all your weight is in the back of the boat, it costs you nothing to move a few things forward.
 

Ladon

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May 3, 2019
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Thanks for your help. I’ll go down a pitch and see what happens. Ill reply soon after testing when the boat gets fixed up. Never seen a prop shaft twist at the splines and the prop didnt show much damage to the eye.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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if your prop shaft is twisted at the splines, replace the prop shaft. that means it took a hit. probably a stainless prop
 

QBhoy

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Normally 4 boxes have a bigger diameter I’m sure. I’d stick to a good 3 blade if you can get away with it at all. Sounds like your current figures are about perfect really.
 

Ladon

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May 3, 2019
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7
if your prop shaft is twisted at the splines, replace the prop shaft. that means it took a hit. probably a stainless prop

Yep, it is a stainless. Thats why im trying to go 4 blade aluminum to give a little when I do hit something. Im letting the shop go through the foot this time because of the fact im afraid it might have twisted the down shaft (power shaft) as well. Wished the prop hubs work like they are made to do!
 
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