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  1. #1
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    2021 rt1888p set up

    You guys with Rt18p’s what kind of hull lift are you getting ?
    Where is the splash line ?
    2021 rt188p , Mercury 115 Pro XS CT , Croxton Razor 4XLR 22 , Z lock 4” jack plate , 8’ power pole blades

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    #2
    Let me elaborate on my set up a little more.
    Jack plate is all the way down . Motor bolted as low on ack plate as it will go , PTP is 5 3/4”.
    Myself in the boat , empty live wells, 3 group 29’s in the back , loaded like I fish.
    90 degree air , 85 degree water.
    5700 rpm (vessel view) , 46 mph (gps) slight chop .
    24 Tempest plus will start to slip right before full trim. Rpm will go to 5800 but speed decreases a tad.
    I’m sure I will pick up a few rpm’s when it cools off , and maybe a few when engine gets more than 18 hrs, but I don’t know how many.
    Even so it appears I’m over propped.
    Boat is not up on pad and running good until almost full throttle and almost full trim.
    Wouldn’t mind a little better mid range handling , but also think it should do better than 45.
    I would appreciate any help from you guys that know more about this stuff than me !
    2021 rt188p , Mercury 115 Pro XS CT , Croxton Razor 4XLR 22 , Z lock 4” jack plate , 8’ power pole blades

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    #3
    Is your motor a command thrust? My original Tempest 23p actually over-revved past 6300, but I didn't have significant slippage when trimmed out. Best speed was 51.7, but water temp was in the 60s, very slight chop, and I took out the aft seat.

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    #4
    Yes Command Thrust
    2021 rt188p , Mercury 115 Pro XS CT , Croxton Razor 4XLR 22 , Z lock 4” jack plate , 8’ power pole blades

  5. Member
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    #5
    I would bet that your Tempest does not have the cupping necessary to get grip and lift. That is unfortunately common that props that come from boat manufacturers do not have proper cupping per Mark Croxton. He did my Tempest that came from Ranger and it made a big difference in grip and lift and therefore speed.

    From what I understand, the 24p Tempest is the right prop for most RT188p's with Merc 115 CTs.

    Yes, you will gain RPMs, grip and speed in much cooler air and water.

    Also, I know MANY RT owners of 188p and 198p say to run the motor as low as you can go. I have never found that to be the case and I have run my 2021 RT198p at evey height under the sun. I have settled on 4" PTP on my Tempest and 3.25" PTP on my Bravo 1 FS. Only thing that happened for me when lowering the motor to PTP measurements like yours was I lost RPMs and speed. At more reasonable and higher motor heights, you will get that 24p Tempest closer to proper WOT RPMs.

    I would also guess you would improve lift or at least require less trim to lift with some more setback. You could go to a 6" jackplate or add spacers to your 4".

    Do not expect the bow to rise high on these boats like many glass boats do. If your experience after tweaking goes like mine has on my 2021 Rt198p, my best setup which is very good the hull runs pretty flat. I can get the spray all the way to the back but without prominent bow lift.

    I know some guys have ground off their transom welds on older models and say they gain lift and speed and no doubt do. I can run 57-58mph with my Tempest with factory transom welds and and happy with that.

    John Walker - Matthews NC

    2021 Ranger RT198P - Mercury 150 4S - Enertia Eco
    VesselView Link - MotorGuide Tour Pro - Lowrance Carbons

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    #6
    Johnny,
    what do you think of your bravo 1 vs the tempest on your 198 ?
    My tempest didn’t like a higher motor height , like I thought it would have.
    Much trim at all and it lost grip . Rpm’s would be around 6000 ,but speed down around 42 with a 8’ rooster tail.
    Would dropping in pitch to a 22 with additional cup be a step in the right direction ?
    2021 rt188p , Mercury 115 Pro XS CT , Croxton Razor 4XLR 22 , Z lock 4” jack plate , 8’ power pole blades

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    #7
    Quote Originally Posted by Madeintheshade View Post
    Johnny,
    what do you think of your bravo 1 vs the tempest on your 198 ?
    My tempest didn’t like a higher motor height , like I thought it would have.
    Much trim at all and it lost grip . Rpm’s would be around 6000 ,but speed down around 42 with a 8’ rooster tail.
    Would dropping in pitch to a 22 with additional cup be a step in the right direction ?
    I like the Bravo a lot. It is maybe 1 sometimes 2 mph slower than my Tempest but superior in pretty much every other category. More grip and lift, better holeshot, better fuel economy.

    My guess is you have some other tweaks that can be done to improve your numbers. Removing any transducers hanging below the pad, eliminating any other things sticking out below the pad/transom edge like transom savers, individual weld beads. Also, moving as much weight as you can from the bow compartments to the stern makes a noticeable difference.

    There is no reason why a Tempest prop with proper cupping and balancing at motor mounting heights in the 4" plus or minus range cannot push a 188p to optimal speeds with reasonable grip. If it cannot, I would be looking for reasons why.

    A Bravo 1 FS is always going to grip much better than a Tempest, even a worked one, and run at higher mounting heights.

    John Walker - Matthews NC

    2021 Ranger RT198P - Mercury 150 4S - Enertia Eco
    VesselView Link - MotorGuide Tour Pro - Lowrance Carbons

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    #8
    Johnny,
    you are running a 22” tempest plus correct ?
    if so what all did Mark do to it ?
    2021 rt188p , Mercury 115 Pro XS CT , Croxton Razor 4XLR 22 , Z lock 4” jack plate , 8’ power pole blades

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    #9
    Quote Originally Posted by Madeintheshade View Post
    Johnny,
    you are running a 22” tempest plus correct ?
    if so what all did Mark do to it ?
    Yes, I have a 22p Tempest Plus I run. Mark balanced and blueprinted it. He added the edge cupping he says it should have had from the start. He also added some tip cup to help with bow lift. I am not sure if the Tempest also should have had the tip cupping from the start and he added only what it should have had or if the tip cup he added was more than a stock Tempest might usually have. In any case, it looks like modest tip cup to me.

    My 22p Tempest will hit my Merc 150 regular 4S max RPM of 5800 even in warm/hot water and will hot 57-58mph. It still wants to lose grip sometimes when trimming up while planning and working towards full speed and trim. It traps some air and has to get rid of it. I am pretty sure this is normal for the Tempest and it's easy to deal with. Otherwise, it is the best all-around 3-blade prop you can run on my hull and motor.

    John Walker - Matthews NC

    2021 Ranger RT198P - Mercury 150 4S - Enertia Eco
    VesselView Link - MotorGuide Tour Pro - Lowrance Carbons

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    #10
    Quote Originally Posted by Johnnyred View Post
    Yes, I have a 22p Tempest Plus I run. Mark balanced and blueprinted it. He added the edge cupping he says it should have had from the start. He also added some tip cup to help with bow lift. I am not sure if the Tempest also should have had the tip cupping from the start and he added only what it should have had or if the tip cup he added was more than a stock Tempest might usually have. In any case, it looks like modest tip cup to me.

    My 22p Tempest will hit my Merc 150 regular 4S max RPM of 5800 even in warm/hot water and will hot 57-58mph. It still wants to lose grip sometimes when trimming up while planning and working towards full speed and trim. It traps some air and has to get rid of it. I am pretty sure this is normal for the Tempest and it's easy to deal with. Otherwise, it is the best all-around 3-blade prop you can run on my hull and motor.
    I really appreciate your help !
    I’ve been waiting on a callback from Mark to talk to him about my situation. Had the boat out again today with a a passenger aboard.
    It was really a dog compared to me only.
    He made the comment that it acted like it need about 2” less pitch and a bunch of cup added. Which were my exact thoughts.
    Boat still popped out of the hole like a cork , but struggled with lift , rpm, and speed . Also still losing bite with much trim making these issues worse.

    What pitch is your bravo 1 ?
    2021 rt188p , Mercury 115 Pro XS CT , Croxton Razor 4XLR 22 , Z lock 4” jack plate , 8’ power pole blades

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    #11
    Quote Originally Posted by Madeintheshade View Post
    I really appreciate your help !
    I’ve been waiting on a callback from Mark to talk to him about my situation. Had the boat out again today with a a passenger aboard.
    It was really a dog compared to me only.
    He made the comment that it acted like it need about 2” less pitch and a bunch of cup added. Which were my exact thoughts.
    Boat still popped out of the hole like a cork , but struggled with lift , rpm, and speed . Also still losing bite with much trim making these issues worse.

    What pitch is your bravo 1 ?
    My Bravo 1 FS is 23p. Merc advises to go 1" pitch more than the pitch of a Tempest that is setup right.

    I would bet the 24p Tempest is the right pitch prop for your setup. There has got to be other things keeping you from realizing ideal numbers.

    Do you have transducers that hang below the pad so they can give readings at speed on plane? Those can really drag your numbers down. Parts of the transom weld bead that you can catch your fingernail on? Areas of paint loss? Is the transducer mounting pad (not sure what they are called) hanging below the weld bead at any place?

    Talk to Mark. Your prop is prolly some or most of the issue.

    John Walker - Matthews NC

    2021 Ranger RT198P - Mercury 150 4S - Enertia Eco
    VesselView Link - MotorGuide Tour Pro - Lowrance Carbons

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    #12
    Back on the water today.
    pulled my transducer of just to make sure it wasn’t an issue. It didn’t make any difference .
    I tried a 23 tempest per Marks suggestion.
    Got my rpm’s up to 6150 -6200 . Speed did not increase and handling got worse.
    The 24 wasn’t giving the lift I needed and the 23 gave less lift than the 24.
    Time to talk to Mark again Monday . Maybe adding cup and B&B will cancel each other out on rpm’s and I can get the lift I need .
    2021 rt188p , Mercury 115 Pro XS CT , Croxton Razor 4XLR 22 , Z lock 4” jack plate , 8’ power pole blades

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    #13
    Been following your posts. I've been experimenting with PTP with my Tempest 24P and Trophy 23P 4-blade. My Tempest had a nick repaired, cup added, and balanced by Mark. Before Mark, my Tempest ran 51.7 at 6300 rpms with a 4" JP and 5 1/2" PTP. The Trophy ran 47.6 at 6300 rpms with same set up. Raised PTP to 4 1/2" in warmer water. Trophy ran 48.1 at 6300 rpms and post-Croxton Tempest ran 47.6 at 6280 rpms. The latter would not fully get on pad until 5800 rpms or so. Splash line was by my seat with almost no rooster tail until 5500 rpms or so. Going to try lowering my PTP to 5" with the Tempest.

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    #14
    Quote Originally Posted by Dmy-rt188p View Post
    Been following your posts. I've been experimenting with PTP with my Tempest 24P and Trophy 23P 4-blade. My Tempest had a nick repaired, cup added, and balanced by Mark. Before Mark, my Tempest ran 51.7 at 6300 rpms with a 4" JP and 5 1/2" PTP. The Trophy ran 47.6 at 6300 rpms with same set up. Raised PTP to 4 1/2" in warmer water. Trophy ran 48.1 at 6300 rpms and post-Croxton Tempest ran 47.6 at 6280 rpms. The latter would not fully get on pad until 5800 rpms or so. Splash line was by my seat with almost no rooster tail until 5500 rpms or so. Going to try lowering my PTP to 5" with the Tempest.
    So after cupping and balancing you lost only 20 rpm , but 4 mph. That makes no sense to me and is the exact situation I’m trying to stay out of.
    2021 rt188p , Mercury 115 Pro XS CT , Croxton Razor 4XLR 22 , Z lock 4” jack plate , 8’ power pole blades

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    #15
    A 24" prop is too much because you're 600rpm off WOT red line. Your thought of getting Mark Croxton involved is a good one. Your situation is why I hate CT motors on a 1300# hull.
    2015 Ranger RT188 DC; BassCat Storage Box; Mercury Optimax 115ProXS;
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    #16
    Made,
    It stumped me as well. All numbers were via GPS and vessel view. I lowered my PTP back to the original 5 1/2" with the Tempest and plan to start over with my measurements. Possible that warmer water accounts for part of the variation.

  17. Member
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    #17
    Update
    I got my 23 tempest back from Mark after blueprinting it. Boat is doing a lot better , but still isn’t quite where I want it.
    Boat still won’t get splash behind console until 3/4 trim. It will sometimes at full trim get up all the way up on pad . However if it does it takes a couple of minutes. What I mean is it seems at wot and full trim the prop is ventilating . Sometimes , but not every time after a minute or so at wot and full trim i will hear and feel the prop grab and hook up. The boat will hop up a bit onto what I consider pad , splash line will move back to the last 2’ of the stern, rpm will drop a bit, speed will go up a bit, and rooster tail disappears.
    Everything about this deal has always screamed drop the motor down more , but it’s as low as it will go.

    Looks to me that I have to get the motor lower or go to a shallower running prop . Probably a 4 blade razor xl.
    Would adding 2” spacers to my 4” jackplate get me the effects of lowering my motor ?
    2021 rt188p , Mercury 115 Pro XS CT , Croxton Razor 4XLR 22 , Z lock 4” jack plate , 8’ power pole blades

  18. Member
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    #18
    Good update.

    Yep I know exactly what you are describing I have experienced it. It is not uncommon for boats like these.

    1. I suspect you will get better results in colder water. But striving for a setup that works well at all temps is understandable.

    2. I suspect that additional setback, either thru spacers or a 6"-8" jackplate, will improve your bow lift.

    3. My personal experience has been that a 4-blade will definitely get rid of the loss of grip and ventilation. For your CT with 4.75" gear, a Razor XL or Bravo 1 FS are the ticket.

    4. If you are going to keep tweaking until you exhaust all reasonable possibilities to maximize lift, grip and speed, you will eventually end up combining additional setback and a 4-blade prop. I suspect you will like that combo.

    John Walker - Matthews NC

    2021 Ranger RT198P - Mercury 150 4S - Enertia Eco
    VesselView Link - MotorGuide Tour Pro - Lowrance Carbons

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    #19
    Any additional speed would be great.
    However what I want most is to get up on pad and ride good at less than WOT.
    As it is now if it gets on pad it’s at max trim and Wot.
    2021 rt188p , Mercury 115 Pro XS CT , Croxton Razor 4XLR 22 , Z lock 4” jack plate , 8’ power pole blades

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    #20
    Quote Originally Posted by Madeintheshade View Post
    Any additional speed would be great.
    However what I want most is to get up on pad and ride good at less than WOT.
    As it is now if it gets on pad it’s at max trim and Wot.
    Yep, in no way, shape or form are the pad versions of the 188 and 198 true lifting hull designs. They ride softer than the non-pad versions for sure but they struggle to lift.

    I am of the opinion that setback really is needed on these hulls. When I got my 198 I did not have a jack plate and thought the 6" of built-in setback would be enough. After finally putting a 6" plate on after a year, the difference was immediate. I could use a little less trim than before. The boat ran faster and handles a little better. I bet 8" of setback on my 198 would be even better.

    I can also say that the Bravo definitely lifts the whole hull better at less than WOT and max trim than the Tempest but is not as fast top end. It is also not as "loose" which is good and bad. There is nothing more fun than running the Tempo fast in conditions where it hooks up well.

    It is possible the Merc Fury 4 prop is another good option for you if you end up experimenting with different props.

    John Walker - Matthews NC

    2021 Ranger RT198P - Mercury 150 4S - Enertia Eco
    VesselView Link - MotorGuide Tour Pro - Lowrance Carbons

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