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  1. #46
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    I am gonna say you are Tilting at Wind Mills.....Don Quixota. You are playing with a 3 blade prop to start with and building in more low Hole Shot Torque....Hence the Bow Lift.

    You need a 4 Blade to lift the Stern and run flat as I never pull anything....But I fly flat and smooth on Glass, wind or even back through my own wake doing 50 MPH and still no Chine Walk. I can slide the stern in a turn and all is still stable and running flat....Check out a 4 Blade SS 20 Plus Pitch.

    Just my opinion and .02 worth

    Karsten

  2. #47
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    Karsten you need to read it again.
    I DO NOT WANT STERN LIFT.. adding cup to the tip is supposed to add bow lift not stern lift.
    I know what the sidewinder is , I owned one of those boats from the original molds, in the uk it was called dateline bikini.
    A 4 blade prop that raises the stern is exactly what I DO NOT WANT.
    I need bow lift not stern lift.

    Yes I get bow lift at the very start, then the prop pulls itself to the surface once under way, this is NOT what adding cup to the tips is supposed to do.
    The whole point of adding the cup is to try and add rake, by adding tip cup it is supposed to act like more rake to the blade thus would give better bow lift.
    This is Not what has happened at all, from the standing start it pulls ultra strong due to having the tips cupped to give more bite plus 3 vent holes in
    the hub. That is exactly what I was expecting from the pull away, so its perfect in that respect.

    But my main goal when adding the cup was for extra bow lift once on the plane.
    I have no extra weight in the boat and made sure nothing is up the front for the test.
    From zero to plane the boat is fast, then she goes over to plane and then the trouble starts, the bow drops too far even with full trim out and the boat
    then becomes incredibly unstable because the back end has come up far too high and the noise from the exhaust is deafening.
    so I trim the motor all the way down and still the hub of the prop is breaking the surface causing exhaust noise as if it had a snout.

    This type of boat has a tendency to ride very flat with the stern up on the water, but this is something else.
    I have a home made jackplate that I sometimes fit to raise the motor so propshaft is level with bottom of the transom, even when I use that normally I
    cannot get as much stern lift as this props now produces even with a srx prop.
    If I had a deep v hull with heavy stern this would be the magic bullet, the stern on my boat is almost flat and Not deep v..

    By cupping the tips it has made the prop want to run surface like a cleaver prop !!!!! and that I cannot understand at all.
    maybe this now needs to run with a jack plate ? I have no idea

  3. #48
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    You are getting a paddle wheel effect. No slip. The prop is trying to climb out of the water. Un settling the boat and torquing the boat to the right, and giving stern lift.

  4. #49
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    Quote Originally Posted by XstreamVking View Post
    You are getting a paddle wheel effect. No slip. The prop is trying to climb out of the water. Un settling the boat and torquing the boat to the right, and giving stern lift.
    You may want to try airing out the prop some (jackplate) to lessen the "paddle wheel effect" or ya might have ta "pound" out some of that tip cup.
    Gary
    "12" Super Lite Tunnel (11') "88" 25 Yammy twin carb "BANANA SPLIT"
    "77" Hydrostream Viper "87" 140 Rude heavy modded w/15" mid, Bobs nose and lwp (in progress)
    "Too much is never enough" Keith Richards " Dreams become reality via hard work and perseverance" G.A.Carbonneau

    "This coming from an old man that strapped two bananas together, hung a motor on it and calls it a boat" XstreamVking

  5. #50
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    yeah I am thinking maybe raise the prop up a bit more to try and lessen the torque, but this has gone completely the wrong way to my thinking.
    and I was wondering if I put enough tip cup in the blades ha ha good job I did not put any more in.
    From around 30mph onwards up to around 40 the boat is terrible, and I mean proper dangerous.
    I have hydraulic steering with no slack in the system and I am fighting left and right like mad trying to stop the boat over turning.
    its bouncing all over the place as if I was in extreme rough water, and yet this is only on the river !!! almost dead flat.
    this is in a boat that normally you can take your hand of the wheel and she will go dead straight on plane and stable too.

    what I did not do is remove the flair on the end of the hub !!!!
    I know this is there to help with heavy stern boats unlike the original convergence rings so I might try taking that off and re-test.
    maybe with the flare the prop is now fighting against itself and trying to do two totally different things ?
    I am a bit puzzled to be honest.

    oh and normally these props like to run deep, I have the motor mounted direct to transom on 2nd hole from bottom, so can only go up 1 more or
    fit my home made jack plate that can take it sky high. ( more like a Frankenstein plate).
    Last edited by phillnjack; 10-06-2017 at 07:42 AM.

  6. #51
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    Leave the hub flair, it is there to help draw the exhaust out of the lower. Next time you do a prop, just mod a little at a time so you can see where you are at.

  7. Likes Slimm liked this post
  8. #52
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    XstreamVking
    I understand exactly what your saying and your probably right,
    but the only mod done to this propeller that is not a very well known modification to just help holeshot was the cup tip.
    Every where I asked I got told the same thing, to get more bow lift you need more rake and to get that from a prop you cup the tips.

    In an ideal world I need a Raker prop, but the rare chance of getting a good used one over here is almost impossible.
    new price is just ridiculous here, and I dont even know if that would solve my problem ?

    I have vented tons of props and never known them to do anything at all to handling or effect planning speeds in any way, so that
    simple mod I dont even count.

    Flare removal and why.
    the reason I was going to remove the flare is because with that removed its the same basic stainless prop as a OMC/Brp REBEL prop.
    the new props with a flare are called VIPER, and the viper is better for boats with a heavy stern.

    when I look at the rebel prop and see reviews it is known to give a little bit more bow lift than the viper but not good for stern heavy boat.

    as for exhaust being drawn out that was the idea behind the original sst with its bronze convergence ring not the flare.
    The flare was mercury's patent just a couple of years after the omc convergence ring hit the scene.
    do the rings or flares work for exhaust extraction ? I dont think so to be honest, I have tried with and without the bronze ring with
    another sst and it does give 1.2mph more top end without the ring but nothing else was altered at all, no handling difference and no difference at slow speed that I could notice on my boat.

    I have seen many Ballistic props have the hub shortened and they then give even more bow lift than normal. the same is done on a few uk race boats with trophy props to give more bow lift.
    it seems the longer the barrel the more bow lift, ut would make sense as the long hub/barrel will act like a trim tab/spoiler type device.

    Any mods I do to the prop would be able to be easily reversed, apart from shortening the hub, that would be the last mod to be done.
    removal of the flare is just cut off the 4 spot welds between hub and flare inside the hub.

    need to re-test the boat and get someone else to drive it while I can see what the boat is doing, sometimes looking from a distance can help to
    suss out what is going on.
    need to talk to a friend of mine and get him to drive the boat while I video from the bank, if he dont drive it I will find another victim
    need to video a normal prop side on then this one to see the actual difference of the level of the boat on the water.
    for safety I will ensure the new test pilot/victim wears full safety gear (ski vest and arm bands ).

  9. #53
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    I have found a driver for my next test ( a real idiot ) who will get in and take full instructions from me while I video what is happening to the boat.
    The new driver has been told what is happening and he thinks its going to be a simple case of sit down at idle and then whack on the throttle to its full extent.
    He is in for a massive shock ha ha , this prop on my boat is lethal for pull away.
    New driver said he dont know much so will be taking full instructions from me at the river bank... ( what a plonker).
    he will be wearing a crash helmet ( this is only so I can relay to him and him being able to hear perfectly through a blue tooth headset.) I will alllow him to even
    wear a life jacket and obviously the kill cord ( dont want boat tearing of down the river and doing a self destruct type thing against a brick wall.)

    The water where testing will take place will be a bit on the cold side, and should be almost dead flat calm with little current.
    I might have a go at rigging up a remote control kill switch as well before the next test, dont realy want to have to go diving for the motor as its running like a dream now.
    Looking from the bank might give me a better idea of how the angle of the boat is now running, I will be having it jacked up a touch more, cav plate 1 inch above water if
    the prop can handle this height should give best top speed results and show if this modification is helping to keep the bow up, or is a total failure.

    I hope to have a video of the test to show results, will show even if a crash happens as it might be a lesson in what NOT to do ?

    oh and test pilot is not married , dont have a girlfriend and his parents hate him, so he is the ideal candidate for the job......

    .

  10. Likes XstreamVking, NICE PAIR, olboatman, Slimm liked this post
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