Top Secret Keel? [Archive]

-XTC-

10-04-2007, 05:37 PM

Ive heard and I am sure many others have as well, the term 'dropped keel' or 'racing bubble' or 'spoon'. The Tom Papp bottom or Irvan Capps worked it, ect... Can someone explain what it is, why it works, maybe who came up with the idea, when it first started - as well as If you have this on your boat, how does it work for you? -Maybe some Pro's and Con's. This may be a beginners question but :confused: I have heard these terms and dont really understand the purpose or theory behind it. Maybe someone has pics?
Darin

McIntyrelocal

10-04-2007, 06:04 PM

this may not be exactly right but im gonna put onw on my boat this winter,but they are there to divert the water directly into the intake and to give the boat a little more lift in the tail.the water fallows the bubble into the intake instead of the water bloing by the intake and only the shoe grabbing as much of the water as it can, if you take a spoon and hold it under the foset on you r sink upside down it explains it all. thats the best way i can put it.

Placecraft Dragstar

10-04-2007, 06:33 PM

-XTC-

10-04-2007, 06:56 PM

Thanks McIntyrelocal, makes some sense. So if you place this on your boat, does that mean you may need to adjust your shoe / loader / ect... possibly?
Again - for me this is just theory as I am happy with my boat, more just questions because I dont understand it.
this may not be exactly right but im gonna put onw on my boat this winter,but they are there to divert the water directly into the intake and to give the boat a little more lift in the tail.the water fallows the bubble into the intake instead of the water bloing by the intake and only the shoe grabbing as much of the water as it can, if you take a spoon and hold it under the foset on you r sink upside down it explains it all. thats the best way i can put it.

-XTC-

10-04-2007, 06:58 PM

PC, I really wasnt thinking to puttin one on my sled, just had some questions regarding the 'bubble' or whatever that I have been thinking about.
But you bring up another, why wouldnt my PC benifit from a bubble?
Putting a drop keel is not for all makes of boats. In your avatar I see you have a placecraft, that is one boat that does not use a drop keel.

Aluminum Squirt

10-04-2007, 07:10 PM

Holding the spoon under the water is the easiest way to explain a spoon. There was a thread awhile back that showed some pretty good photos of it in action. Essentially the water will follow the spoon and when it comes off the spoon it ends up pressurizing the intake pretty well. The fast whitewater racers use them because if we put a shoe/loader etc on the underside of our boats, it would promptly be ripped off by a boulder or sandbar. Seems like the whitewater boats run out of steam at about 120-130 MPH making me guess that a spoon is not very efficient above those speeds. Keep in mind this is a very extreme generalization as there could be a lot more at work here like set-up, hull design, HP etc. Anyway, if you have access to a fast whitewater boat, you should see a spoon. There is a lot of voodoo surrounding spoons, some will let you see there's, others not so much. Most are made out of bondo (at least on whitewater boats) and are even changed between races. Sometimes you even get lucky enough to hit something just right, and you pick up a few MPH, probably added a dent in just the right spot or changed your spoon a little. Anyway, I know nothing about them in a lake boat, however I was informed that people do use them on the lake. Hope this helps a little. Maybe if Xero reads this he'll post up a picture of a spoon for you-Aluminum Squirt

McIntyrelocal

10-04-2007, 08:17 PM

Thanks McIntyrelocal, makes some sense. So if you place this on your boat, does that mean you may need to adjust your shoe / loader / ect... possibly?
Again - for me this is just theory as I am happy with my boat, more just questions because I dont understand it.
yes you adjust the shoe depending on how aggressive your boat can handle some boats do wierd things just have to try different setups same with the loaders depends on horse power and type of hull but you usually try different things with all settups wether a boat has a round keel or flat keel but my boat needs the tail lift and from what i hear flat keel boats are a lot harder to get the settups just right.

JETBOY03

10-04-2007, 08:21 PM

darin you have to stop trying to figure out ways to go fast and let me catch up.

-XTC-

10-04-2007, 09:12 PM

I will keep it below 80. ;)
darin you have to stop trying to figure out ways to go fast and let me catch up.

1968Droptop

10-05-2007, 06:43 AM

GREAT question Darin. Here's another, I know the spoons are quite common on 19' Daytona's, TPR's, etc. Can a 21' Daytona benifit from one ?
P.S. Austin, I think you'll need a few more ponies to catch up with Darin ;)

TRG

10-05-2007, 06:59 AM

10-05-2007, 10:06 AM

most definitly! you are just allowing for more lift and less drag with the outside sponsons and if it is done correctly, the boat will perform very well
Taking motor placement, HP+tq #'s, hull weight etc. is also a necessity to adding a drop keel!
Todd
????? why does this sound like a sales pitch? the only purpose of the bubble is to create a low pressure area in front of the intake on a boat that's already so fast, it's barely in the water. it doesn't do anything to "create lift". in a slower boat, all it will do is create more drag because you're already deep enough to obtain all the water you need. if you have adequate suction pressure at absolute top speed, you don't need it. if you have to drop the shoe/loader strakes to an unsafe depth to maintain suction pressure, the bubble is an option to try to direct water flow up into the suction piece by creating a low pressure area in front of it.

H20MOFO

10-05-2007, 10:16 AM

i know what a spoon is but not a drop keel. is it the same thing? i was going to ask the same question 68-drop did. (21' daytona benefits)

TRG

10-05-2007, 01:19 PM

????? why does this sound like a sales pitch? the only purpose of the bubble is to create a low pressure area in front of the intake on a boat that's already so fast, it's barely in the water. it doesn't do anything to "create lift". in a slower boat, all it will do is create more drag because you're already deep enough to obtain all the water you need. if you have adequate suction pressure at absolute top speed, you don't need it. if you have to drop the shoe/loader strakes to an unsafe depth to maintain suction pressure, the bubble is an option to try to direct water flow up into the suction piece by creating a low pressure area in front of it.
What element that i typed is not true?:confused:
...and BTW,..."Sales Pitch"? you sound like you had too much red bull and wheaties this morning!
whenever i feel like you sound i usually get laid! helps out with my attitude!
Todd

supersoaker509

10-05-2007, 03:07 PM

anyone have some pics
I also would like to know if it would help a Daytona 21 running over 90

H20MOFO

10-05-2007, 05:22 PM

??? same as a spoon ?

Vern S

10-05-2007, 06:30 PM

whenever i feel like you sound i usually get laid! helps out with my attitude!
Todd[/QUOTE]
:D :D

H20MOFO

10-05-2007, 06:35 PM

vern OMG thats way too wierd i have nitro fish on my bow and stern and frig.

10-06-2007, 08:00 AM

What element that i typed is not true?:confused:
...and BTW,..."Sales Pitch"? you sound like you had too much red bull and wheaties this morning!
whenever i feel like you sound i usually get laid! helps out with my attitude!
Todd
yah, too much coffee, wife outta town for a few days, blah blah... rip its by the case...
adding a bubble/spoon/droppedkeel, or whatever name people want to call it, won't add lift. the "if it is done correctly" part seemed kinda salesy, and what is interesting is that about 90% of the time these things are built into really fast/light race boats, they have to be modified several times to fine tune. the "concept", developed from racing fast and light daytonas/cheyennes/etc., somehow get's carried over to lake layup moderate speed boats where it makes no real performance difference; i.e., 600+ lb 90mph boat.
on faster lighter tunnels, <500lbs, 118 or more, it can make a difference because the intake will be very shallow/close to the surface and can be subjected to unloads just due to speed/depth. when shoe/loader tuning is exhausted, and these unloads are still occurring, this modification can help by creating a low pressure area (at high speed) directly in front of the intake which causes water to flow UP, directing flow into the intake.
suction presure and your hardware tuning efforts are going to tell you whether or not you need one, and whether or not it is tuned correctly. and let's not even get into where this came from.

jrork

10-06-2007, 09:15 AM

Good thread Darin.
For what it's worth, here's Panthers attempt at a spoon. I'd love to see some other designs
http://i63.photobucket.com/albums/h157/jrork/IMG_0202.jpg
http://i63.photobucket.com/albums/h157/jrork/IMG_0200.jpg

pacman

10-06-2007, 09:39 AM

yah, too much coffee, wife outta town for a few days, blah blah... rip its by the case...
adding a bubble/spoon/droppedkeel, or whatever name people want to call it, won't add lift. the "if it is done correctly" part seemed kinda salesy, and what is interesting is that about 90% of the time these things are built into really fast/light race boats, they have to be modified several times to fine tune. the "concept", developed from racing fast and light daytonas/cheyennes/etc., somehow get's carried over to lake layup moderate speed boats where it makes no real performance difference; i.e., 600+ lb 90mph boat.
on faster lighter tunnels, <500lbs, 118 or more, it can make a difference because the intake will be very shallow/close to the surface and can be subjected to unloads just due to speed/depth. when shoe/loader tuning is exhausted, and these unloads are still occurring, this modification can help by creating a low pressure area (at high speed) directly in front of the intake which causes water to flow UP, directing flow into the intake.
suction presure and your hardware tuning efforts are going to tell you whether or not you need one, and whether or not it is tuned correctly. and let's not even get into where this came from.
ITS GREAT TO HEAR SOMEONE GIVING THE CORRECT INFO , THERES NOT TO MANY PEOPLE WHO REALY UNDERSTAND THE CONCEPT BEHIND IT, THEY JUST WANT TO HAVE ONE PUT ON SO THEY CAN SAY THEY HAVE ONE. I WORKED WITH TOMMY ONE OR MORE TIMES AND CAME UP WITH EVEN NEWER IDEAS .WE TRIED ONE WITH MY DAYTONA AND IT WORKED BETTER THAN WE THOUGHT.
BAD HABIT RACING 951-734-4606

holorinhal

10-06-2007, 10:45 AM

I know that Eliminator Daytonas are built with either a flat keel or a round keel. Is the Round keel, on a Daytona a different principle that is throughout the entire keel area, from a spoon and/or dropped keel?
Can a hull have a rounded keel and a spoon/dropped keel?
I have an Elim Daytona project, not sure of the exact weight but seems to be a lighter layup , that I will be working on in the future .It has a flat keel. I want to add a rounded keel, just want to know if the round keel is different from the spoon?....Hal

-XTC-

10-06-2007, 02:07 PM

yah, too much coffee, wife outta town for a few days, blah blah... rip its by the case...
adding a bubble/spoon/droppedkeel, or whatever name people want to call it, won't add lift. the "if it is done correctly" part seemed kinda salesy, and what is interesting is that about 90% of the time these things are built into really fast/light race boats, they have to be modified several times to fine tune. the "concept", developed from racing fast and light daytonas/cheyennes/etc., somehow get's carried over to lake layup moderate speed boats where it makes no real performance difference; i.e., 600+ lb 90mph boat.
on faster lighter tunnels, <500lbs, 118 or more, it can make a difference because the intake will be very shallow/close to the surface and can be subjected to unloads just due to speed/depth. when shoe/loader tuning is exhausted, and these unloads are still occurring, this modification can help by creating a low pressure area (at high speed) directly in front of the intake which causes water to flow UP, directing flow into the intake.
suction presure and your hardware tuning efforts are going to tell you whether or not you need one, and whether or not it is tuned correctly. and let's not even get into where this came from.
This is the best so far I have heard it described thanks BP, So the question is then, although I have heard that my PC wouldnt benifit from one (spoon - bubble) --would it? running over 30lbs of intake pressure @ WOT @ over 100.
Does anyone have any pics of other Spoons, dropped Keels? Thanks John for the pic of yours, and I know alot of racers dont want to send out pics of thier bottoms but without measurements and testing it really wouldnt do anybody any good other then an Idea of what they look like would it?
Just a thought. Also - is this pretty much a daytona - cheyenne thing? and if your boat is >500lbs but does run in the high teens would it benifit?
Darin

sleekcrafter

10-06-2007, 02:18 PM

My buddy has a keel section cut out of a Papp tunnel, along with the intake. Maybe Rob can post this up if he wishes to. It has very good detail to the bubble.

396_WAYS_TO_SPIT

10-06-2007, 06:27 PM

My buddy has a keel section cut out of a Papp tunnel, along with the intake. Maybe Rob can post this up if he wishes to. It has very good detail to the bubble.
Why is the section cut out of the boat:confused:

sleekcrafter

10-06-2007, 07:17 PM

Why is the section cut out of the boat:confused:
out of a wrecked boat I believe, not 100% certain thou, got it from one of his buddies boats

Placecraft Dragstar

10-07-2007, 03:37 AM

Why is the section cut out of the boat:confused:
So he can use it to hang on the garage wall

1968Droptop

10-07-2007, 08:00 AM

bp, your saying intake pressure is the main thing to check to see if you need a spoon (ass-u-ming the rest of the bottom is right) ? I didn't get a chance to hook up a gauge to my pump this past summer, so I don't know my pressure at speed. I'm just wondering out loud if they can help out a 21', or is it only the 19's ?

Jet Hydro

10-07-2007, 12:28 PM

Heres the one I built on the Hydro.
I call this more of a dropped keel then a spoon/bubble because of it`s length.
http://www.hotboatpics.com/pics/data/500/4213P1020166.JPG

-XTC-

10-07-2007, 06:18 PM

Nice Pic Jet Hydro! Thanks

PE826

10-07-2007, 06:40 PM

This is not as pretty as jet hydros but heres mine.
http://inlinethumb55.webshots.com/21366/2042685550069608869S425x425Q85.jpg (http://rides.webshots.com/photo/2042685550069608869vdDAzI)

djdtpr

10-07-2007, 10:01 PM

PE826

10-08-2007, 03:04 AM

I agree with dj. Don't now everything about why it works, but it works.

edog_103

10-08-2007, 08:26 AM

HMMMMM seems like alot of talk about this but also alot of different ideas about what it really does. Maybe people should listen more and talk less. I spent alittle time watching Tommy do a few different bottoms and having him explain what he was doing and why but ill let the pros that are posting tell ya what it does.
I was watching tommy set one up, one saturday afternoon. Asked him how he new how high and how long to make it for each boat. He gave me that "classic look" and just continued to work.

Unchained

10-08-2007, 03:34 PM

One thing I found after three + seasons of recreational boating and dozens of passes at 115 + was that the drop keel on my TPR Stealth separated from the intake where it laps down onto the leading edge. It was added by TPR when the boat was new. The drop keel was made of fiberglass and was not able to take the flexing between the keel and the intake. I talked to a friend who also had a Stealth and raced PE with it and he had the same problem a couple different times. The repair was to cut the bubble at the line where it lapped onto the intake, re-epoxy it back onto the intake and put a bead of silicone between the two. It held after that repair.
Another thing to watch for.

H20MOFO

10-08-2007, 04:27 PM

drop keel= long and skinny. spoon= round(er). or at the end of every drop keel there is a spoon. in those pics i'm not seein what i thought was a spoon. i guess what i'm askin are they always used in conjunction or seperatley or both?

George Pataki

10-08-2007, 04:45 PM

-XTC-
Darin here are a few pics of a dropped keel I did to my Flat keeled Daytona.
definatley helps load the pump! Before doing the modification the only way to make this boat go fast was to run 5/8 Bellow the keel on the shoe. "VERY SCARRRY" on shut down
http://www.arsmarine.com/gallery/albums/userpics/10001/normal_Copy_of_scott_wilson_pics_007.jpg
http://www.arsmarine.com/gallery/albums/userpics/10001/normal_ScannedImage~0.jpg

Placecraft Dragstar

10-08-2007, 05:14 PM

A TPR boat won smokin in the cove a few years back and he dont have a drop keel. He went like 142mph in a 1000ft

djdtpr

10-08-2007, 06:41 PM

A TPR boat won smokin in the cove a few years back and he dont have a drop keel. He went like 142mph in a 1000ft
Ive never seen a dropped keel on a TPR they arent a flat keel boat the keel is already droped in the mold,all Tommy ever did was add a bubble for the hp you were gonna run and the weight of the boat.
EDOG i can picture him doing just that looking at you over the top of his glasses with that, you wouldnt understand if a drew you a picture look!

-XTC-

10-08-2007, 07:18 PM

Thanks George!
Looking at the pics of yours and of PE826's bottoms, My PlaceCraft looks similar, not sure if it actually is a 'bubble' or 'spoon' or whatever but it definetly resembles those, - maybe a somewhat rounded keel perhaps, where it starts at close to the tip of the center pod and runs back almost to the intake opening. (like yours pictured below) So if I understand what is being said here, it seems like it is possibly a way to increase intake pressure (if needed) without running way too much shoe depth. So what then would be a good amount of bowl pressure? I have heard people stating 70+ and others saying 25+... ?
Darin
-XTC-
Darin here are a few pics of a dropped keel I did to my Flat keeled Daytona.
definatley helps load the pump! Before doing the modification the only way to make this boat go fast was to run 5/8 Bellow the keel on the shoe. "VERY SCARRRY" on shut down
http://www.arsmarine.com/gallery/albums/userpics/10001/normal_Copy_of_scott_wilson_pics_007.jpg
http://www.arsmarine.com/gallery/albums/userpics/10001/normal_ScannedImage~0.jpg

edog_103

10-08-2007, 07:30 PM

Ive never seen a dropped keel on a TPR they arent a flat keel boat the keel is already droped in the mold,all Tommy ever did was add a bubble for the hp you were gonna run and the weight of the boat.
EDOG i can picture him doing just that looking at you over the top of his glasses with that, you wouldnt understand if a drew you a picture look!
I wanted to buy a boat from him just so I could push his buttons and have him say "That's not how we do it around here".

396_WAYS_TO_SPIT

10-08-2007, 11:16 PM

So he can use it to hang on the garage wall
or have it powdercoated BLUE:) :) :) :)

Placecraft Dragstar

10-09-2007, 01:20 PM

Thanks George!
Looking at the pics of yours and of PE826's bottoms, My PlaceCraft looks similar, not sure if it actually is a 'bubble' or 'spoon' or whatever but it definetly resembles those, - maybe a somewhat rounded keel perhaps, where it starts at close to the tip of the center pod and runs back almost to the intake opening. (like yours pictured below) So if I understand what is being said here, it seems like it is possibly a way to increase intake pressure (if needed) without running way too much shoe depth. So what then would be a good amount of bowl pressure? I have heard people stating 70+ and others saying 25+... ?
Darin
There is only one way to set up a placecraft ( depending on what intake you have) once you have your shoe depth made then come off that for your ride plate then your nozle angle. Then set your air plates and there is three settings to those depending on how loose you want the boat to feel. Make sure the engine is set the right measurement from transome and the gas tank then your seat. Go out and run it and the only thing you have to adjust once you have all this is your nozle angle. Then when you have it running good then like I said adjust your air plates for how loose you want the boat to feel.

Johnwithjm

10-12-2007, 08:59 AM

A TPR boat won smokin in the cove a few years back and he dont have a drop keel. He went like 142mph in a 1000ft
Yep that was Donnie Little. I think he was the only jetboat that has won the 6 second class at the cove.

Pops@Aggressor

10-12-2007, 11:13 AM

Heres the one I built on the Hydro.
I call this more of a dropped keel then a spoon/bubble because of it`s length.
http://www.hotboatpics.com/pics/data/500/4213P1020166.JPGWhats UP You Ski Rider!
When you run that do you get a bloody nose from being so high. Hay Am I seeuing a elavation raise between the bubble and Intake or is it a photo thing.

Pops@Aggressor

10-12-2007, 11:14 AM

Pops@Aggressor

10-12-2007, 11:40 AM

-XTC-
Darin here are a few pics of a dropped keel I did to my Flat keeled Daytona.
definatley helps load the pump! Before doing the modification the only way to make this boat go fast was to run 5/8 Bellow the keel on the shoe. "VERY SCARRRY" on shut down
]
Dang George- That Keel Looks like it could load 3700 HP It must be a thing with the picture's - Tom Put some more Bottom on the molds and all had a Load effect. When Steve Strange had the molds Tom had to work all of them very hard to get them to run. What only the TPR Guy's (Bad Habits) know is what Tom was doing on his last hulls- He was inovating again just as he had done with all others. another major change and its working.
DO NOT -I SAY DO NOT ever copy JET HYDROs like pictured. That is a Hydro Modified to run a Jet, and Tech should require he have a Pilots Lic for that thing. Heck his sponsons never get wet. I had a Blown Gas Sanger Hydro (MAI TAI) 35 Years ago and know the front sponsons are for packing air to be dispersed across a flat surface bottom. If he ever put ailrons on the sponsons he will be able to TACO this thing Up & Down the whole course. His only problem is East L.A. don't have a Lake to show off to all the Hydrulic Low Riders there. Got Ya!