porpoising at higher speeds
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porpoising at higher speeds

  1. #1
    gets 'em wet ultrajet's Avatar
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    Default porpoising at higher speeds

    I have searched quite a few threads here and it seems that porpoising at higher speeds is a relatively common phenomenon. Since I've added the droop and some wedging my boat rides great up to 55mph-60mph but just as my secondaries begin to open up and start to really haul a$$ the boat begins to bounce and I have to trim down out of it. Will adjusting the rideplate help at all?? Currently it is set to 2.5* relative to keel. Tried bring it up a bit to 4* but it drives and turns like crap(reverse bucket below angle of plate at this point). Will bringing the rideplate down do any good? Haven't heard of anybody placing their rideplate even with keel.

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    Senior Member GT Jets's Avatar
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    The ride plate adjustment will help IMHO, there are many many hulls out there that do not respond well with a droop.

    The whole idea of a droop is to air the boat out with more bow lift, you either need to add a buttload of horsepower/speed, redistribute the weight forward (moving the center of gravity forward) or take out some droop.

    You may find the bouncing with only show up when you run out of acceleration/HP....That is telling you you don't have the thrust required to keep the hull stabilized.
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

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    Quote Originally Posted by GT Jets View Post
    The ride plate adjustment will help IMHO, there are many many hulls out there that do not respond well with a droop.

    The whole idea of a droop is to air the boat out with more bow lift, you either need to add a buttload of horsepower/speed, redistribute the weight forward (moving the center of gravity forward) or take out some droop.

    You may find the bouncing with only show up when you run out of acceleration/HP....That is telling you you don't have the thrust required to keep the hull stabilized.
    Putting the droop on definitely helped me pick up speed. I feel the boat come out of the water really well. If I ease into it there is not such a problem but if there is a little chop or I accelerate too quickly it starts to buck like a bronco. Did you mention dropping the rideplate may help??

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    Senior Member GT Jets's Avatar
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    Quote Originally Posted by ultrajet View Post
    Putting the droop on definitely helped me pick up speed. I feel the boat come out of the water really well. If I ease into it there is not such a problem but if there is a little chop or I accelerate too quickly it starts to buck like a bronco. Did you mention dropping the rideplate may help??
    It may if it is either neutral or high now...giving some down plate with give the pump something to push against...

    It is easy to test (completely reversible things are a great place to start).
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

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    Senior Member BrotherWolf's Avatar
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    ride plate adjustment like said should do the trick

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    Senior Member W.O.T's Avatar
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    How Much Wedge Did You Add?

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    Quote Originally Posted by W.O.T View Post
    How Much Wedge Did You Add?
    2* up wedge. Boat porpoised with just droop at cruising speeds, adding a little wedge helped that out significantly. Tried 2* down but boat ran like crap, again the nozzle/reverse bucket drags.

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    Senior Member W.O.T's Avatar
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    I would Try A Straight Snoot. My Last Boat Was A Vhull And Always Had A Porpoise At A Cruising Speed With A Droop. But Wide Open It Ran Great. I Would Gps It And See If The Droop Is Really Helping You. Some Boats Work Better All Around Without A Droop. I Always Kept The Droop On And Just Dealt With The Slight Porpoise. I Didnt Have A Rideplate Though. Hopefully Adjusting That Will Help You. Does Your Hull Have A lot Of Hook In It?

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    Quote Originally Posted by W.O.T View Post
    I would Try A Straight Snoot. My Last Boat Was A Vhull And Always Had A Porpoise At A Cruising Speed With A Droop. But Wide Open It Ran Great. I Would Gps It And See If The Droop Is Really Helping You. Some Boats Work Better All Around Without A Droop. I Always Kept The Droop On And Just Dealt With The Slight Porpoise. I Didnt Have A Rideplate Though. Hopefully Adjusting That Will Help You. Does Your Hull Have A lot Of Hook In It?
    I would love to try a straight snoot. Problem is I have AT trim(steering) so finding a "loner" or used one is a biatch so I'd end up havin' to buy one which may end up being a total waste. My boat does have a speedometer and the speedo without question indicates improvement in speed with the droop. I've studied the bottom of the boat pretty well and I can't find any hook/rocker in it. Pretty flat from keel all the way to intake. My rideplate is a tad warped, not sure if that is creating any issues or not. I guess I shouldn't complain so much since boat rides great up to 60mph but it would sure be nice to let her fly every now and then and not have these issues.

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    classic hot boater Orange Peel's Avatar
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    I had the same problem you are having, My boat is a bubble deck v-bottom and the boat have droop,shoe,plate,PD... the boat ran the lake very well but at 80 you had to drop the GPS and hang on? I went to greg shoemaker with the problem.
    He told me to go up 4* with the ride plate and go 4*up in wedge. I have not got the boat in the water yet to see if this helps, Will have it in the water this week.
    I will let you know if it helps?

    Also how thick is your ride plate? It could be flexing at high speed??
    Never forget where you come from,no matter where you are going.

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    Quote Originally Posted by Orange Peel View Post
    I had the same problem you are having, My boat is a bubble deck v-bottom and the boat have droop,shoe,plate,PD... the boat ran the lake very well but at 80 you had to drop the GPS and hang on? I went to greg shoemaker with the problem.
    He told me to go up 4* with the ride plate and go 4*up in wedge. I have not got the boat in the water yet to see if this helps, Will have it in the water this week.
    I will let you know if it helps?

    Also how thick is your ride plate? It could be flexing at high speed??
    Interesting... I kinda thought that increasing the wedge might make it worse. I really can't go to 4* with my plate 'cause it rides like crap(nozzle/reverse bucket falls below plate angle). I was thinking go down to 1-2*. Shows you how clueless I am My plate is the standard AT 19"x7" . I think it is about 1/8" thick or so. Let me know how it goes this week.

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    Senior Member DuaneHTP's Avatar
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    If you have the ATJ steering nozzle, you can use the R6201 Extension. It is similar to the Snoot

    http://www.americanturbine.com/

    Look under Products, then under performance parts.

    Duane HTP

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    Quote Originally Posted by GT Jets View Post
    .
    The whole idea of a droop is to air the boat out with more bow lift,

    I thought A droop snoot is design to create lift on the aft end of the boat????

  16. #14
    Senior Member Fonz69's Avatar
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    Quote Originally Posted by W.O.T View Post
    I would Try A Straight Snoot. My Last Boat Was A Vhull And Always Had A Porpoise At A Cruising Speed With A Droop. But Wide Open It Ran Great. I Would Gps It And See If The Droop Is Really Helping You. Some Boats Work Better All Around Without A Droop. I Always Kept The Droop On And Just Dealt With The Slight Porpoise. I Didnt Have A Rideplate Though. Hopefully Adjusting That Will Help You. Does Your Hull Have A lot Of Hook In It?

    I agree with WOT

    The straight snoot would be a better way to go

    With a staight snoot you are not bending the water again too

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