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Thread: more top end speed?
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01-29-2008, 11:31 PM #1
more top end speed?
Looking advice on getting a fer more top end speed
Why
I barefoot and my fat butt needs to go faster, or lose weight. The weight loss isn't working so I need to speed the boat up.
I have a 2007 Outback with about 100 hours on it. When I took it in for the 100 hour oil change and service I asked the dealer about a prop to get more top end speed, but they could not decide what I needed.
One guy said go up in pitch the other said down, they were still discussing it and I just walked off.
opinions?
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01-30-2008, 12:15 AM #2Senior Member
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Not sure what you pitch is now? But to gain more distance per revolution you must increase your pitch. If a prop says 13 x 13 that is the diameter and the pitch with the pitch being the amount of forward travel in inches per revolution. So a 13" pitch goes 13" per revolution and a 14" goes 14". Inboards are around 13/14 Outboard props are 15, 17, 19, 21 and 23 but remember an outboard goes thru a gear box and is NOT a one to one drive.
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01-30-2008, 03:09 AM #3
You want to go up in pitch to a 17 or a 19. It'd be best if you could find someone who'd let you try b4 you buy.
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The 19 may be pushing it, though.
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Hope this helps
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BLearn all you can today. Tomorrow you may need to know it!
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2004 Moomba Outback. Tower Speakers, amp, ballast, ssrr ... she's a cutie!
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01-30-2008, 06:24 AM #4
How much speed are you looking for? I have seen comments, either here or on Skifly, that these hulls are designed for max of about 46-48. Take that with a grain of salt....
If I understood it correctly, as the boat tries to go faster the hull actually starts to come down and thus increases drag, thus limiting speed.
I did not even know you could get a 19 for an inboard?
Maybe stainless might be a choice?
Are you long line or on a boom?If you believe something to be true, it will be - in it's consequences.
2009 MasterCraft ProStar 197 - DD - 5.7L - 325HP - Zero Off
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01-30-2008, 07:06 AM #5Senior Member
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more pitch = more top end until you run out of horsepower... I'm with butta try b-4 you buy. If you are running a 13 pitch now try to jump to 15 and work from there. how much mph do you feel you need?
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01-30-2008, 12:17 PM #6
Word of caution.....more pitch will also pull engine rpm's down some, so it'll have to be a balancing act. Good advice on starting with the 15...it may do the job just fine.
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BLearn all you can today. Tomorrow you may need to know it!
.
2004 Moomba Outback. Tower Speakers, amp, ballast, ssrr ... she's a cutie!
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01-30-2008, 07:25 PM #7Sled491 Guest
everthing is a trade. More speed = less hole shot. Try calling the boys at OJ props, they'll talk to you and if they can't firgure this out for you no one can. PS you were right to walk away from a mechanic that thinks less pitch = more speed. More blades won't do it for you either so don't get sucked into that one either. If pitch won't get you there they might have something in the blade or cup design that would work for you
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02-04-2008, 08:44 PM #8Banned
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I agree with sled, call OJ and they will tell you exactly what you need, that way, you won't have to make and educated guess.
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02-06-2008, 04:25 AM #9Senior Member
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If we are to believe the folks at Waterski Magazine, they say the prop on the 08 Outback is a 13"x11 prop. You should determine your starting point before moving up in prop size. So perhaps a 13 or 14 pitch prop would do the job, if you are starting with an 11 pitch prop.
Please remember to post your results once you get the new prop.
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02-06-2008, 05:12 PM #10Senior Member
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Not saying you are wrong but maybe the magazine? Seems like the standard inbooard skiboat (DD) prop for the last 20 years was a 13x13? We are talking about direct drives and old but well proven American V-8 engines, whether it be the Ford Windsor 351 or the Chevy 350, they turn about the same RPMs. You would usually see that the top ends of all these boats was from 45 to 48mph.
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