40hp props on suv17

Discussion in 'Prop Shop' started by topnative2, Jun 25, 2011.

  1. topnative2

    topnative2 Well-Known Member

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    What props are being turned on the 17suv w/ a 40hp and the top rpm your obtaining?
    Decisions?????
     
  2. Josh

    Josh Well-Known Member

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    Topnative2,
    On my Native SUV17 I have a 40hp 2011 Nissan/Tohatsu. The stock 3 blade aluminum prop had a strong mid range and the best top end of the props Ive used. I kept it on thru the motor breakin period. This was with the motor's cavition plate roughly 1 inch above the bottom surface of the hull. The top 300- 500 RPM the torque curve seemed almost flat (no increase in speed). It had good grip and decent hole shot. I also have a jackplate and trim tabs. With this stock prop, if I did not use the tabs, the boat would porpoise. With minimal tabs the nose drops and the ride smooths out. To answer your question depends on what you are trying to achieve. Running very shallow? Jumping on a plane quickly? Heavy load with multiple passengers? I believe its a matter of compromises. I settled on a Powertech SWC3R12PTN40. This was recommended to me by Marcus of Powertech to meet my requirements. I was going to elevate the motor to run shallow, would be running in weeds, so would need to have good holeshot, running WOT and turning quickly, needed good grip and no cavitation, but would like to keep as much top end as possible. The 4 blade SS selection would load the engine too much and significantly reduce top end. This prop is a 3 blade SS with alot of cupping. It works great to all my expectations. One note, you have to have trim tabs to make it work. The hull works best with this prop at the highest elevations on the jackplate and tabs used partially down. With this setup the boat is nearly level in the water. Some top end is sacrificed, but the handling is retained. My GPS is not working currently, but the last time it was I was seeing roughly 30-31mph. The props torque seems to be in the bottom half of the RPM range. This is where I use it the most so it meets my needs. The negative to this setup, reverse is almost non existent. Kinda of like an airboat.
    Hope this helps.
    Josh
     

  3. topnative2

    topnative2 Well-Known Member

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    Josh,
    thanks for the info... I am only looking for basic performance meaning hitting the allowable rpm.
    After reading your input it brings up more ques. regarding hp,prop, and tabs.
    1. what was the pitch of the stock prop and new prop?
    2. Did lowering the jp eliminate using the tabs to get rid of the porpoising?

    I have no need to run shallow just want get her propped rt. and I am leaning towards a 13 7/8 x 17 (for  a 40hp etec)
    but maybe going up to a 19 because the suv is so light.
    Just trying to find out what's working out there
    life should be so tuff ;)


    topnative2
     
  4. out-cast

    out-cast Well-Known Member

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    I have a 40hp(stock prop) on mine and easily see 33mph with a decent load at 5300rpms. I tried a smaller pitch, gained rpm but lost speed. I wanna try the stock prop in stainless next.
     
  5. topnative2

    topnative2 Well-Known Member

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    what pitch are u running?
     
  6. out-cast

    out-cast Well-Known Member

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    Stock 11.1x13 aluminum
     
  7. Gramps

    Gramps Living & Dying in 3/4 Time

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    I'm late to the party....

    Stock prop 11x13 no jack plate hit 5800rpm & 36mph (Scary fast to me)

    Stock Prop, TH Marine Jack Plate - Bad news. Blowing out in turns, rough chop, etc. I never had the opportunity to run WOT.

    Turning Point Props 11 pitch, TH Marine Jack Plate, 32mph, Very Punchy hole shot  :eek: 5750rpms but Cavitation plate was only ~4 above transom.

    Turning Point Props 13 Pitch w/ Proprietary Cup, TH Marine Jack Plate, Sluggish hole shot, 5400rpm, Cavitation Plate ~5.5" above transom, top speed 33mph.

    I'm going with a custom built stainless 3 blade prop with a proprietary cupping once I get the setup dialed in.  It's only (HA!) $310 for the custom prop which is still a lot of money, but for a prop tuned for my application and that costs about the same as an off-the-shelf model. Ya, I'm sold!
     
  8. topnative2

    topnative2 Well-Known Member

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    thanks for the info

    ck out-- propmd.com-- good info one of Brett's old ones