Education on props??

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JETTYWOLF
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Education on props??

#1

Post by JETTYWOLF » Sun Jun 16, 2013 5:13 pm

I have a 3 blade stainless prop, 14-1/4 X17 R on my boat now.

Never reach over 5300-5500 RPMs, depending on wind behind or on bow, number of passengers, and is the tide screaming....

Saw what was maybe a great deal on a 4 - blade Honda prop: 13 3/4" x 24

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Does anyone know what this would do, TO ME, or FOR ME?

<<<OR>>>

Should I just give a different 3 blade a try? And should I be getting straight to 5500 or better RPM's straight away??

-Versus a slow build up as I go??



I hear all the dock talk. And have a buddy with a very light 22' Hydrasports rolled edge plastic boat, under powered with a 2-stroke Evinrude Ficht 150, and he raves about going to the correct 4 blade, on his boat.

CLUE-LESS? Yes, that's me...But my ears be OPEN to someone who knows their stuff, and has a boat like mine.

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Sabs28
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Re: Education on props??

#2

Post by Sabs28 » Sun Jun 16, 2013 7:58 pm

Long story short. Damaged my 3 blade Mercury prop, 13&1/4 X17. Purchased a "Turning Point Hustler" 3 blade 13&1/4 X17, On test run I noticed RPM's were at 6300 @ WOT & lost 3 MPH :shocked: . Ordered another "Turning Point Hustler" in a 19 pitch & it brought me back down to 6000 RPM & got my 3 MPH back :clap: .

So if you are looking to gain a few more RPM's, Drop your pitch 2 inches. But as I have learned a "17" pitch from one prop manufacturer MAY not be the same as another, So be carefull with what brand you buy. Call or e-mail who ever you are going to buy the prop through & see what they say.

I also noticed with the slower prop the boat gets on plane VERY EASY & VERY QUICK & handles a loaded boat alot better :highfive: .

I DO NOT have any experiance with 4 blade props. :popcorn:
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Re: Education on props??

#3

Post by JETTYWOLF » Mon Jun 17, 2013 7:20 am

I'm dealing with all HONDA.

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Sabs28
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Re: Education on props??

#4

Post by Sabs28 » Mon Jun 17, 2013 9:45 am

Then buy a HONDA prop with 2 inch less pitch. :idea:
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JETTYWOLF
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Re: Education on props??

#5

Post by JETTYWOLF » Tue Jun 18, 2013 6:26 am

whoa that would be a pretty small prop, huh......coming from a 14-1/4 x 17 Honda prop now?

Okay, I guess no one knows anything about 4 blade props. And by the time I fish out I'm sure it will be sold anyhow.

Was just curious. I'm so far behind this month, I can't pay attention. So, never mind.

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Re: Education on props??

#6

Post by Sabs28 » Tue Jun 18, 2013 7:54 am

You can still do your homework, & get educated on the subject, pick out the prop you want & buy it when the time arrives. No harm in being prepared.
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pjay9
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Re: Education on props??

#7

Post by pjay9 » Thu Jun 20, 2013 1:38 pm

Some info for you...A 4 balde will run smoother less vibration...but with a relatively small OB sized prop you may not even notice it being smoother while underway...but in bigger size for IB larger boats with speeds around 10 to 20 knots..you would know. Another blade means more resistance in the water so the picth will need to become less than a 3 blade. On an OB the diameter is critical in order to clear the cav plate...plus there is an optimum distance for the tip to be passing by the underside of the plate...all very techincal and complex...if you get bubbles you loose push/thrusrt..then everything else suffers. Many blades have a cupped edges which basically is worth an inch in pitch.

On my old heavy charter boat of decades ago I had a 24" x 24" 4 blade (nickname for that is a square wheel)...I wanted thrust at lower RPM since the boat would not plane no need to try...issue was if you pushed the revs up the engine would start to heat up...so all of this prop stuff is complex and you surely can go to your local prop fixer and talk to them...also as said go to the H dealer...they will have a solution for size...then look for that on the internet.

On my 90 Yam..I changed pitch and RPM comes up nice to proper top end range and cruise revs are good and speed dif can't tell! In fact I could most likely go to another pitch change (less) and get to the top of the rpm range, but why...this works well for my loads.

With your boat load situations it may be nice to get the top of the top end rpm range when empty, so then when loaded you can get to the lower end of top end rpm range. Does that make sense...!

Think of it this way that tiny little prop when compared to what it is pushing is amazing and complex and a cool invention! Have fun figuring it all out! PJ
2009 Raider 185 Pro Fisherman, 2005 90Yamaha, 2012 Yamaha9.9HT, 2008 EzLoader roller, 2004 Dodge TCD dually, 2005/2015 Lance1161

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Re: Education on props??

#8

Post by goatram » Thu Jun 20, 2013 9:27 pm

Dave 2" of pitch drop for going to a four blade is about right and You might see a rpm rise as well. I have a 15" Dia. X 17P 3 blade props on my 250s. I tried 4 Blade 15" X 15P. 6450 RPM and a drop of 8 MPH. It did Jump up on plane Real Fast but my cruise speed dropped as well at 4000 RPM.
Mine are Powertech Props. I will Second calling some one local to buy and try out different props. They will want to know what you have already. Wt of boat, What you want out of it. ie Speed, Fuel eco, Planing ability,. The local guy will be asking you a bunch of questions. Props cost me $525 plus shipping and tax a piece.
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Re: Education on props??

#9

Post by JETTYWOLF » Fri Jun 21, 2013 4:53 am

AHAH....finally more info.

Thanks everyone. Because I had no real knowledge at all about the Prop issue.

Reason I was asking a guy on Ebay in SC who I bought my battery cables off of for my spare Honda, had several brand new Honda props.
And they were super deals. $189, $200, $250 but they were 3 and 4 blades of various sizes.

The auctions are over now, OF COURSE. So he may or may not still have them. But in the "interim"...(fancy word) I have bought another action camera.

OPPPS :mrgreen: So I'm back Po' again.

Was out "solo" yesterday and yes, 1/2 tank of fuel 75 gallons, and just me I can get only 5300 RPM out of the 225 Honda. SOOOOOOOO,

-I'll assume, the prop I have is a bit too large in pitch???

So, if a good deal on a Honda prop (plain ole 3 blader) comes around I ought to try LESS PITCH. Is what I'm getting out of this. Keep the same size?

PJay, yeah Props are one of those things that if it ain't broken. Don't fix it. For me, over the years.

I'm assuming

WHY, I don't know. That when Pacific puts a boat out, rigs the engine, that they're giving you the best overall prop?

Best not to assume anything though. I know.

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Re: Education on props??

#10

Post by goatram » Fri Jun 21, 2013 6:51 pm

Dave
Call Jeff @ North Harbor Propeller up in my neck of the woods. He used to work for Powertech Propellers As I said you will need some info; Weight of boat, Model of engine, make , model, and size of prop, current max RPM. He has the numbers in his head. Different makes and sizes of props do work differently on different boats.
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Re: Education on props??

#11

Post by pjay9 » Fri Jun 21, 2013 11:54 pm

Jetty, As you said you were running light and only hit 5300...so what it means you are getting more thrust for lower RPM and thusly some fuel economy...but loaded and you pushed her it would seem to me the engine will get hotter as it is working hard...but then when you are loaded...do you go on plane that much, then it probably doesn't matter...BUT if you go on plane the engine has to be sort of lugging equal heat equal not good for engine...so here's what I'd do.

I think the range for your engine is 5500 to 6500 RPM...install a prop so when you are running light at WOT you get close to 6500...that will be less but still in range when loaded at WOT...then pull her back for cruise while on plane...should be around 15-16 knots for most planing boats, then all will work well and fuel eco good and speed decent.

On my boat I turn about 5800 WOT light at 29 kts..back off to 4000-4200 drops to 19-21kts, run her when engine sounds sweet...of course my tach only shows 100's...hate that!

Anyway a good prop guy will help you fill in the blanks...tell him what you said re the RPM and your prestent prop size...ususlly stamped on the hub...he'll most likey will have you take at least 2" out of the pitch...BTW the SS one do not flex as much as Alum...so there is some diff there too...he'll tell you if he is knowledgable. BTW make sure you don't have any hull issues..dents, stuff dragging, rough spot on bottom...that will always be bad fro speed.

Will be anxious to hear what you find out and change too. PJ
2009 Raider 185 Pro Fisherman, 2005 90Yamaha, 2012 Yamaha9.9HT, 2008 EzLoader roller, 2004 Dodge TCD dually, 2005/2015 Lance1161

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