new to RDP need setup help on a fast 25 step v bottom

[25worldclass]

Hey guys I have a 25 foot warlock worldclass 25 step v pad boat with a 572 with a 4 liter whipple supercharger 1000 - 1100 hp Imco scx/sc combo on a 7 inch mercury ITS box 24 inch tabs set horizontal on the 2nd strake. The boat currently runs well over 110 gps but only for short bursts before it starts to porpoise and climbs completely out of the water and reenters on the step first few hops its cool then things get violent. the rear starts to prop walk sideways then the usual v bottom chine starts to make direction changes and it becomes a handful very quickly. I have removed cabin interior which helped me hold 2 or 3 more mph and improved things. two extra adults in the back seat calms it down nicely but kills 5 plus mph. I know that the boat is going too fast and I'm an idiot for putting this much power in a v so I don't need the lectures about the dangers I have been around fast boats and offroad cars my whole life and I'm well aware of my stupidity. I'm loooking for someone that is familiar with fast v bottoms that might share some real experience on how to get this boat to take a better set. I have the power to be a solid 115 mph boat but cant hold it wot long enough to get it there. best so far was 114 gps crab walking it about 5 or so degrees and ready to go swimming. not fun. Any help would be great, I'm trying to get it figured out before desert storm next year and actually for the Lake of the ozarks shootout next year.

 

[Andy B.]

114mph is very impressive for that hull that thing moves!! Very jealous!
Sorry I can't help you, it would be nice to see the a pic of the boat and your setup. A lot of knowledge here I'm sure someone can give you sound advice good luck.

 

[25worldclass]

Thanks Andy I will try to get a pic soon the boat is clean and fast originally built for the race boat driver for warlock in 02 from what I understand they ran a factory stock class of some sort with it a few times heavy layup great rough water boat it ran 111 at desert storm this year but was embarrassing how poorly it handled the boat does not like smooth or lazy water at all. It loves big chop though. pic was from lake of the ozarks shootout last year 101 mph under trimmed and nosing in hard upon reentry

 

[poncho]

Huevos Grande

 

[port austin pirate]

dont know what tabs your running but longer tabs might help, that and maybe a large plastic Jesus on the dash, way to fast for 25 v

 

[sonicss31]

Maybe try get a call thru to Tyler Crockett. He is the fastest single engine v-bottom guy at the shootout.

 

[25worldclass]

been playing with weight distribution which has been helping also need to go see my prop guy he helped with the attitude after I installed the 572 pre whipple tabs are 24 eddie marine. And yes its too fast for a 7 foot wide v bottom for sure but it shocks the crap out of alot of faster single engine cats which makes it real fun when it acts right but thats not very often these days. i have been considering something in the 28 to 30 range for tabs also straight on the outer edge, not tapered in like the eddie's. i have also seen one that has a short skeg running 2 or 3 inches deep on the outer edge

 

[25worldclass]

Tyler Crockett is a great idea not sure why I did not think of him.

 

[havasujeeper]

280 K-plane's?

 

[25worldclass]

Havasujeeper I grew up in upland

 

[Hammer]

Can you post a picture of the drive in the neutral position on the trailer from
A side view?

This will help look at x dimension and tab location.

 

[25worldclass]

prop centerline is 3.5 below bottom of pad at neutral

 

[25worldclass]

boat likes about an inch up on the drive and an inch or so down on tabs in lake chop

 

[25worldclass]

it just has a ton of lift all the time which seems to drive the nose in

 

[25worldclass]

-2 sc with a 1.5 spacer scx upper

 

[25worldclass]

bravo 1 merc labbed 32 pitch 4 blade with the barrel cut short also have a non lab 30 barrel cut. 1.36 gears . the 30 handles better the 32 is a little bit faster but has way more lift and chine walk-prop walk

 

[havasujeeper]

I have the same boat, with the Merc 454 h/o. It was the first mold popped, and it is a rough chine walk over 70. We added the 28" K-planes, which helped a bit. We also moved the batteries to far port and starboard for balance, which helped some more. I hope you get the answers you're looking for, and I'll be watching intently.

 

[25worldclass]

From what I was told mine was built with 800 hp or something like that when i got it the boat had the ITS box with a xr imco sc combo with a 496 ho merc in it. It ran 76 mph with almost zero chine walk. I promptly had the 572 built 768 hp and it got a little loose but safe at 91 mph so i put the bigger drive on it with the -2 lower and it settled down and still ran 90. Then along came the whipple 1000-1100 ish hp and it was un driveable above 45 mph with the -2 so i put the 1.5 spacer in it and it got better but not great. since then i have been playing with trim weight balance and have gotten it a long way. at first i could only drive it 4800 rpm before it would get ugly then i started cutting barrels on the props playing with trim removing cabin interior and its gotten better but still cant use all the power whenits just 2 people or worse when alone in the boat now 5600 rpm is doable but getting real loose 6200 with 4 people and my 30 pitch the 32 knocks about 200 to 250 rpm off but is faster by about 4 or 5 mph or so. the boat just gets up on the prop and then it starts to have a mind of its own.

 

[25worldclass]

I have been told to go deeper with the drive but im afraid it will just climb that much higher out of the water and possibly get worse but i dont really know where to go at this point. alot of my improvements have been seat time maybe 50/50 seat time vs setup improvements

 

[Andy B.]

I also have a 25' mid cuddy my goal with my boat was close to 80(which never came to be with my rebuild I was at 72 wirh original motor)I would have been happy as shit! You sir have balls like bull riders

 

[Good Stuff]

Are you the one that ran in the desert storm shootout? I saw some impressive speed from one this year but it looked like a handful. If that wasn’t you maybe that guy could help a little or confirm same characteristics with different setup and save you some money by comparing to your current setup. My buddy’s dad was pretty involved with Warlock (I think he owned the molds at one point if not still) but he didn’t seem to really know hull/setup specifics so I don’t think he would be a good resource for you.

 

[hallett21]

Sounds like you have way too much stern lift. Have you talked with a legit prop guy?

I’m wondering if your lower unit bullet is causing the lift. Meaning is it too low in the water?

 

[n2otoofast4u]

I don’t have much to add other than in all my “fast” junk the Bravo props were not the answer at big speeds. I always saw handling improvements with other prop options.

 

[25worldclass]

Yep that was me at desert storm also ran it at lotto last year but could only drive it 101 in that shootout before it would get ugly but that was literally 3 weeks after installing the whipple so I had no time to get it figured out.. as far as the lower being too low im not sure about that its only 3.5 below the bottom. when i first installed the blower it was a -2 and it was undriveable so i installed the 1.5 spacer and it seemed to get better. I need to go see my prop guy he has always improved things for me with previous props as far as handeling and speed that is on my list of things to try. Unfortunatly the shootout water seems to be the boats least favorite type of water fairly smooth with a lazy swell in those conditions the boat always sucks. its actually pretty good at just over 100 in 3 foot chop but it still gets upset randomly. And yes as far as i can tell its just got way too much stern lift. 2 extra adults in the back seat and its 105 to 107 and pretty stable in most water. 99 percent of the time its just me and my girlfriend who by the way is down for the sketchy e ticket ride but i can tell it scares her on occasion. would love to figure this stern lift issue out so that we can be as safe as possible while letting it eat. what other prop options do you speak of ? i have tried hydromotive and merc 5 blades the boat hates those way too much stern lift and they just lay the boat over under acceleration and even worse when you let out of it. I have been considering trying an scx-4 with a cleaver i have a freind that has a couple laying around and he will let me play with them. he also has quite a few props. my thought is the higher gearcase with bigger prop and long skeg might help.

 

[fastenuff3]

Yep that was me at desert storm also ran it at lotto last year but could only drive it 101 in that shootout before it would get ugly but that was literally 3 weeks after installing the whipple so I had no time to get it figured out.. as far as the lower being too low im not sure about that its only 3.5 below the bottom. when i first installed the blower it was a -2 and it was undriveable so i installed the 1.5 spacer and it seemed to get better. I need to go see my prop guy he has always improved things for me with previous props as far as handeling and speed that is on my list of things to try. Unfortunatly the shootout water seems to be the boats least favorite type of water fairly smooth with a lazy swell in those conditions the boat always sucks. its actually pretty good at just over 100 in 3 foot chop but it still gets upset randomly. And yes as far as i can tell its just got way too much stern lift. 2 extra adults in the back seat and its 105 to 107 and pretty stable in most water. 99 percent of the time its just me and my girlfriend who by the way is down for the sketchy e ticket ride but i can tell it scares her on occasion. would love to figure this stern lift issue out so that we can be as safe as possible while letting it eat. what other prop options do you speak of ? i have tried hydromotive and merc 5 blades the boat hates those way too much stern lift and they just lay the boat over under acceleration and even worse when you let out of it. I have been considering trying an scx-4 with a cleaver i have a freind that has a couple laying around and he will let me play with them. he also has quite a few props. my thought is the higher gearcase with bigger prop and long skeg might help.

see if you can borrow a 0 drop drive with your spacer.then start changing spacer 1/2 at a time till it drives good.drive way to high for a v.i have a 290 hallett with 900 horse mid cabin and run a 1.5 spacer. the drive was set up to high from factory.you could not drive it with anybody in open bow.the spacer settled the stern lift

 

[25worldclass]

how far below the bottom is your prop centerline when trimmed neutral with a standard lower and a spacer

 

[25worldclass]

I'm thinking of ordering a 2" spacer from imco and talking to my prop guy if it does not work out I can sell it to a customer down the road.

 

[fastenuff3]

I'm thinking of ordering a 2" spacer from imco and talking to my prop guy if it does not work out I can sell it to a customer down the road.

it is very rare to need a negative drive on a step bottom v.my set up would be different because of open bow and my boat is a battle ship compare to yours. i needed drivabilty not just speed. it still run low 90s in lake trim and i have never been by myself.

 

[25worldclass]

yeah the only reason mine has a -2 is because I got the drive from a friend-customer for free I would have bought the 2 inch spacer but imco was out of stock at the time and I was in a hurry to get to lake of the ozarks shootout

 

[GregG]

What year is the Warlock ? Trim tabs on that Carter serp pad V are in the wrong location for the speeds you are pushing. Do you have full dual ram hydraulic steering? Take a photo with a straight edge and a a truly level boat to see (and measure) where the drive bullet is in relation to the pad bottom.

That's the start. From there more to follow......

 

[HCP3]

I ran across this website. You and others might find it interesting.

Vee Hull and Vee Pad Design by AeroMarine Research

Vee hull design secrets, vee pad design, porpoising, chine walk, free powerboat articles

www.aeromarineresearch.com

 

[DWC]

dont know what tabs your running but longer tabs might help, that and maybe a large plastic Jesus on the dash, way to fast for 25 v

The only ones with bigger balls are the 2 “extra” passengers. Damn.

Look forward to seeing the progress on this @25worldclass . Hell of a build.

 

[GregG]

I ran across this website. You and others might find it interesting.

Vee Hull and Vee Pad Design by AeroMarine Research

Vee hull design secrets, vee pad design, porpoising, chine walk, free powerboat articles

www.aeromarineresearch.com

I have worked with Jim on stuff in the past. Wealth of knowledge.

 

[25worldclass]

Greg... boat is an 02, centerline of propshaft is at 3.5 inches below the bottom of the pad, steering is mercury racing ITS box full hyd dual ram drive is pushed back 7 inches with that setup. Should the tabs be set on the v instead of horizontal ? I have been planning on longer tabs and have spoken with quite a few people about mounting orientation horizontal vs on the v and I have gotten mixed feedback some say on the v is better some say horizontal on the strake is better. i have driven boats both ways and it seems like on the v tends to drag outward scrubbing more speed when pushed down but you do get alot more reaction from them just not sure how much reaction you want at the speeds im running. My tabs seem to do quite a bit when they are touching the water that is. The boat does not seem to react well to trim and tab changes meaning it has a certain spot that it likes things and it seems to be that spot only for all water conditions, speeds etc... It has always been a set it and forget it kinda boat as far as the tabs go approx 1 inch down on tips of tabs is what seems to work best in all conditions as far as drive trim goes it varies ever so slightly from smooth to 4 feet of chop I only move the drive a few degrees at most. Rough water seems to be the boats best friend. It was verry happy at ozarks in 4 to 5 footers but obviously cant run 100 plus in that stuff in a 25

 

[GregG]

The gearcase bullet is 51% of the assembly drag and the skeg adds 9%. With your assembly setback have you ever strapped the boat to get a handle on the true CofG? IMO the tabs should ultimately end up on the V but that comes after several other things are investigated as I read of the hop you are experiencing. The CofG is very important up at those speeds on a raised pad V hull.

 

[25worldclass]

I have not strapped the boat yet but I'm planning on doing it later this week after I'm done with an engine install in another boat I have a huge A frame with 2 hoists on it so I can easily lift it and find the balance point. Do you know where it should be I have been reading about balance and I have heard 1/3 from transom, 25 percent, and a few other opinions. I think one guy even chimed in and said backrest of drivers seat lol. That was on another forum. I also checked the bottom for hook yesterday and there is some but pretty minimal and I'm not sure that it effects me much since it does not spend much time in the water anyways. It is only in the centerline of the pad on the ridge of the v out to the first strake. The strakes are flat but that hull has a semi v on the pad and that has very minimal hook it is almost perfectly semetrical almost like it was put in on purpose. I have seen bad layup before where the hook was accidental and it's generally not the same on both sides.

 

[GregG]

The CoG is normally 28 - 30% of the length of the hull, measured from the transom. You are pushing speeds that hull has never seen so I would slide it back to maybe 26. The World Class hull is 24 degree deadrise and the raised pad has a few degrees of deadrise built in where most raised pads are dead flat. Post up when you strap it.

 

[25worldclass]

I strapped the boat today COG is at 6 foot from the transom which is right at 24% pretty much full of fuel no passengers that puts the strap right at the back of drivers seat id say with 2 people it should be darn close to the 26 percent number maybe a tadd higher with a cooler but we generally run light on junk. i dont carry a bunch of crap in the boat. The lady and I a cooler, sand spike, box anchor, 2 dock bumpers, very small tool kit and thats it my under seats and storage are empty.

 

[25worldclass]

I'm surprised I kind of expected it to be farther forward judging by how it drives. like I said before if I run my 30 pitch prop things get somewhat better but it costs me mph although my 32 makes it slightly lazy compared to the 30 maybe lower the drive another 1/2 inch lab the 30 and have them pitch it up a tadd and see what she does ? any other ideas are also welcome. I'm not the type that gives up so I will get it eventually. If I can get it to run 115 with a reasonably safe attitude I will be satisfied. Probably, maybe, for a while anyways.

 

[poncho]

I'm surprised I kind of expected it to be farther forward judging by how it drives. like I said before if I run my 30 pitch prop things get somewhat better but it costs me mph although my 32 makes it slightly lazy compared to the 30 maybe lower the drive another 1/2 inch lab the 30 and have them pitch it up a tadd and see what she does ? any other ideas are also welcome. I'm not the type that gives up so I will get it eventually. If I can get it to run 115 with a reasonably safe attitude I will be satisfied. Probably, maybe, for a while anyways.

That is Smokin in that boat.

 

[GregG]

Now that you have the CoG verified and in the correct location I would next talk with both Hill and BBlades on props. At what speed does the 25 start to hop exactly? There are better options than what you are running although they might be a bit limited because you need so much pitch. I think you mentioned that barrel had been shortened on your current prop, make sure you tell them that detail. Before tabs and drive discussion you need to try a couple of wheels on loan for comparison.

 

[25worldclass]

I have used hill on all my previous prop changes with good luck. Before the whipple the boat ran 86 mph with 1.50 gears and a 28. Hill labbed, pitched and changed the blade shap on the 28 and and picked me up to 90.6 mph and improved handling. The boat ran same exact speed with labbed a 30 but was lazy getting there and I'll handling. I will go see hill soon with both my props and see what kind of magic he can perform. When I stepped into the scx I went to 1.36 gears because I knew the boat did not like bigger props. Any time I have stepped up in pitch I have battled with torque roll and transom lift. I will be running the boat today. Hopefully I will have time to get to so cal to see hill soon. Then maybe try a 2 inch spacer vs the 1.5, who knows. The boat constantly has a slight porpoise but really starts hopping around 100 mph. The hop gets ugly around 107 and above that it's a dice roll sometimes it's OK for a bit but it just takes a small anything in the water to upset it at those numbers.

 

[GregG]

At 100 that cut barrel is not helping you. Also run a 6' straight edge from the transom up the length of both sides of the raised pad and see if there is any daylight.

 

[25worldclass]

Hmmm..... I cut the barrels on the props because the boat drives really ugly with the full length diffuser left on it. I was told by cutting them short it will settle the rear down in the water better is that not true ? The handling seemed to get alot better with them cut short. With them in stock form it seemed to push the nose in quite a bit harder. Maybe I should start with new props when I go to hill to have them done. I can always let the prop guy make the decision on barrel length and if I need to cut them later after labbing.

 

[GregG]

Hmmm..... I cut the barrels on the props because the boat drives really ugly with the full length diffuser left on it. I was told by cutting them short it will settle the rear down in the water better is that not true ? The handling seemed to get alot better with them cut short. With them in stock form it seemed to push the nose in quite a bit harder. Maybe I should start with new props when I go to hill to have them done. I can always let the prop guy make the decision on barrel length and if I need to cut them later after labbing.

Testing = Truth. I stand corrected in your application. Very interesting.

 

[25worldclass]

Does a cut barrel normally not reduce stern lift ? I was always told with higher drive heights or boats that tend to get the prop close to surface the flare on the end of the barrel will push the drive up out of the water farther.

 

[GregG]

Now I am confused. I thought you had cut a "straight" barrel but you are saying it had a flare at the end of the barrel?. What model prop are you running anyway?

 

[25worldclass]

I'm running a bravo 1 four blade prop and I'm having the flare on the end of the hub area cut back about an inch just enough to remove the flare

 

[25worldclass]

Using the mercury racing prop slip calculator I'm at around 12 percent slip with 4 people in the boat at 105 mph with 1.34 gears turning a 30 pitch prop at 5600 rpm.

 

[fastenuff3]

Does a cut barrel normally not reduce stern lift ? I was always told with higher drive heights or boats that tend to get the prop close to surface the flare on the end of the barrel will push the drive up out of the water farther.

you are correct