Set up Advice for getting a hull to take a set

[dry]

Seeing as how there seems to be real knowledge and advice on this site compared to the others, i need to know how to go about getting a sanger gull type hull to take a set on the water. the motor from the back of the heads is 32" from the transom, either a 8 or 10 degree super strut "can't remember at the moment" Its a bbc with approx 650 hp and is turning 6200-6500 rpm 11.50x15 2 blade. and when you release the down pedal at speed it porpoise and wont' settle down unless you give it a some amount of down pedal all the time. I have even let a veteran drive it and it does the same thing with him. Its a bbc with 650 hp and is turning 6200-6500 rpm 11.50x15 2 blade. The cav plate is adjusted where it is almost inline with the hull , but I have noticed when you put a 4' straight edge across the rear cav plate side to side that the straight edge stays square all the way across untill you reach approximately 4" on either side of the center of the plate in which there is about and 1/8 to 1/4" gap in the straight edge before it goes back to square again. It appears the cav plate is following the contour of the hull which puts a small arc in the cav plate. So this appears that sanger put a small degree of angle in those particular flat bottoms. What is the proper way to set these type hulls up so they will take a set and run without porposing when you get off the down pedal?? I welcome all opinions and suggestions what ever they may be from all you guys years of experience..........I tried to explain this where it made sense from a newbie.............
Thanks

[poncho]

I am waiting for the info on this one, i am attacking my cav plate tomorrow in anticipation of this years first ride now that i have a plate that will respond

[RiverRacer]

Lot of variables there but what is the shaft angle????, but even if you have an 8 degree angle what is the distance from the back of the tube of the strut to the transom?, motor seems kinda far back??. But one reason it won't take a set is because with that big prop and whatever gear you have you don't have enough power to pull it you're down 1500r's, before you do anything drop the gear and free up the motor and see what it does, the way it is plate settings don't mean anything, as you said you have to be down on it all the time so no matter where you set it you'll still be on the down to keep the boat down sinse it won't take a set!..

[gfinishline]

I read that and now I will say this: leave the gears alone. Run a smaller diameter prop. If your boat was rigged by Sanger, it's an 8 degree strut and 32" IS a little far back. Try a 10 7/8" X 16 two blade prop. Move it back, 5/8" (nickles in coupler-what ever) When this starts to 'pick up speed', Re-adjust the center 6 turnbuckles UP 1/2 of a revolution. This will put the center of the plates at 1/16" UP and the ends down/level with the hull bottom. When this starts to 'pick up speed', re-adjust the left (port) outside turnbuckle UP 1/2 turn. If all of your levers are the SAME LENGTH, STOP HERE! If they are LONGER TO THE RIGHT, turn the outermost right side turnbuckle UP 1/4 (test) and then 1/2 turn (along with a 1/4 turn UP on the left outermost turnbuckle at this point) for the least amount of drag. GOOD LUCK ONE CHANGE AT A TIME WITH WRITTEN NOTES AT EACH TEST!

[RiverRacer]

And that's providing the bottom is "right"!.........

[dry]

I will post the measurement from the trailing edge of the prop shaft strut this evening.

[Moneypit]

Make ONE CHANGE at a time, just ONE. This is after the initial changes George has recommended. Once in the ballpark, record everything, write it down. If you don't have a GPS, get one. Make sure you have an accurate tattletale tach. Minute changes in rigging can have a huge change in how the boat works, but without a GPS you may never know which prop, prop placement, plate setting is best. The "feel" of the boat is one thing, the actual performance is another.........MP

[dry]

Ok, here is what i found out tonight before any changes, the strut is an 8 degree strut the caselle is a 61000-2, the prop is a precision 11.5x15, the prop barrel has a 1" space between the leading edge of the strut and the prop barrel, the strut barrel trailing edge is 25.5" from the trailing edge of the cav plate, the cav plate is 9.5" wide from the transom to the its edge, the stop collar on the down pedal is against the stop collar at rest, leaving the cav plate down at rest at least 1/8".

What does 61000-2 mean? What does the -2 mean?

[gfinishline]

Seeing as how there seems to be real knowledge and advice on this site compared to the others, i need to know how to go about getting a sanger gull type hull to take a set on the water. the motor from the back of the heads is 32" from the transom, either a 8 or 10 degree super strut "can't remember at the moment" Its a bbc with approx 650 hp and is turning 6200-6500 rpm 11.50x15 2 blade. and when you release the down pedal at speed it porpoise and wont' settle down unless you give it a some amount of down pedal all the time. I have even let a veteran drive it and it does the same thing with him. Its a bbc with 650 hp and is turning 6200-6500 rpm 11.50x15 2 blade. The cav plate is adjusted where it is almost inline with the hull , but I have noticed when you put a 4' straight edge across the rear cav plate side to side that the straight edge stays square all the way across untill you reach approximately 4" on either side of the center of the plate in which there is about and 1/8 to 1/4" gap in the straight edge before it goes back to square again. It appears the cav plate is following the contour of the hull which puts a small arc in the cav plate. So this appears that sanger put a small degree of angle in those particular flat bottoms. What is the proper way to set these type hulls up so they will take a set and run without porposing when you get off the down pedal?? I welcome all opinions and suggestions what ever they may be from all you guys years of experience..........I tried to explain this where it made sense from a newbie.............
Thanks

Here your plate is "almost inline with the hull", now you say it's down 1/8" ! Which is it? Look, moving the prop back is done when you go down in prop diameter (well I do) and it actually lifts the tail ,not the nose. Next, we need to know where your 'levers are' and this effects what happens next. Go to the port side of your transom, look across the back of the boat. Where are your levers located when the handle is in it's most UP, released position? (2 o'clock, 1.30?) If your levers are anywhere around 3 o'clock, it's time to START OVER! If they are infact at 1.30 (clock position) then you need to adjust the turnbuckles as I suggested before. Do you have an 'override pedal and spring'? The UP spring pressure must be of a great enough amount to hold the plate (s) up at top speeds.

[dry]

Here your plate is "almost inline with the hull", now you say it's down 1/8" ! Which is it? Next, we need to know where your 'levers are' Go to the port side of your transom, look across the back of the boat. Where are your levers located when the handle is in it's most UP, released position? (2 o'clock, 1.30?) If your levers are anywhere around 3 o'clock, it's time to START OVER! If they are infact at 1.30 (clock position) then you need to adjust the turnbuckles as I suggested before. Do you have an 'override pedal and spring'? The UP spring pressure must be of a great enough amount to hold the plate (s) up at top speeds.

George,
I am pretty sure its at least 1/8" from what i have seen.when i said almost inline i didnot realize that small of a difference would matter but at least 1/8" down is accurate with the down pedal up against the stop collar. As far as my pedals and stop collar here is a pic of what i have "its like what sonny glide" has. Yes i have more than enough springs to keep the plate from sucking down. I am trying to verify this procedure since i don't have a handle as you mentioned above, all i have is the 2 pedals and the down has a stop collar.
http://www.v-driveboat.com/vweb/attachment.php?attachmentid=107&stc=1&thumb=1&d=1207591649http://www.v-driveboat.com/vweb/attachment.php?attachmentid=106&stc=1&thumb=1&d=1207591615

[SonnyGlide]

looks like mine alright....I moved the collar back so all I have is Down, Art and the rest of the crew said I'd never C UP. I'm 100% sure I wount either,
I went 35 mi. non stop on the shake down, and used 2 locks outta 4 and it cruized fine at 35mph, spray was just behind me.;)
I've been watching this thread, and G's got about the Best way of spalin'n this plate issue for newB's
Thanks G;)
Man If I could just get my Sanger and sbc 406 to run anywhere near sm.blk. Mikes, I'd B one Happy Biker, Freak'n Video iz off the hook

[dry]

I agree that the up pedal will never be used, BUT we have to be able to get our flatbottoms to be able to take a set to be able to run em, i want my boat to be able to come out of the hole and be able to take a set and run with out having to pedal it to keep it from porposing............I want it to set on its tail and loosen up alittle and run, its fine to be able to set the locks and cruise mine does that fine and it will run thru the approx 1/4 decent right now, but you have to constantly pedal it and i know the hull is still to wet..................

[FC-Pilot]

I don't mean to be a pain, or to say George can't get you to where you need to be, but I have a crazy idea. There is a guy on one of the other boards that has a Sanger like yours and he has spent years getting it just right to take a set. It might not be a bad idea trying to chase him down and seeing how close your initial measurements are to his. If they are close you may be just some tuning away. If not you may need to look into making some changes to get where you need to be.

Does that sound crazy George? I just figure it might save you some time in trying to tune this thing from a keyboard.

Paul

[Terrible toy]

Dry, did you check the bottom for a hook? As an aside, unless you have a very heavy spring on your double pedal you'll have to get on the up to hold the plate from sucking down at speed.

[dry]

I had an ex runnerbottom racer look at the springs and says they should be plenty to keep it from sucking down. also has said looked like sanger put a little hook in that style bottom............He's drove it numerous times and can't get it to set, but he also says hes not familiar with the gull style flat bottom. Thanks for all the suggestion. I think someone around here can get me close if not there if they can continue to put up with me............

[gfinishline]

If the hull has "measurable" hook in it, I don't think plate settings will CURE the problem. You said, "get the tail to loosen up a little", in a previous post. If the nose is bouncing and the tail is dragging, just move the prop back (a liitle) and test. Release all of the "stops" on the control rod. Stop collar should be firmly against the "up stop guide plate". Levers should be at (look across the transom) "1 o'clock" when up. Set the plates (as listed prior post), since your springs are 'up to the job'. Run the boat. Make accurate notes of RPMs and where spray comes out. If it bounces, put 2 nickles in the coupler, repeat test. What changed? More or less bounce, more or less RPMs, same, what? If you end up with "$9.00 worth of nickles" in the coupler, just to make the boat settle down, it's time for a change! If you have only 2 glass front buckets, 1" of motor movement = 3" of prop movement! A smaller diameter prop will make this "change and test" deal go faster and the boat will go faster (16 pitch) with less work. Give this a shot, before spending money!

[dry]

Ok Thanks for the help i am going to adjust the plate, my levers are at about 1to20 looking from port side when all locks are out and collar is resting against the stop.I guess i will start adjusting the plate up. I don't know about the prop going smaller unless i can cut it down, but for now i will start adjusting the plate up...Thanks again

[Terrible toy]

http://i291.photobucket.com/albums/ll317/terribletoy/Chargerflat.jpg

Dry, you mentioned a "gull wing" bottom. This 69 Charger ski boat built by Ron Edhe had a concave bottom that was an ellipse that went from about 1/2 inch deep in the center made a gradual curve to about a foot from the chine and then made a sharper drop. It was an early runner attempt. Is the "gull wing" on your boat like that?

Anyway this boat set as you see it the picture taken at Lake Ming. It was an 80 to 90 mph deal with an 11 1/2 X 15 Menkins and 12 gears. The hull had a slight rocker and I set the plate dead flat with the bottom with the right turn buckle down an 1/8 or slightly more. It didn't have pedals, just a handle. I would set the boat with handle at launch and forget it. Don't know if this will help any but thought I would pass it along. Good luck with your boat, I know how frustrating it can be to chase bugs.

[RiverRacer]

looks like mine alright....I moved the collar back so all I have is Down, Art and the rest of the crew said I'd never C UP. I'm 100% sure I wount either,
I went 35 mi. non stop on the shake down, and used 2 locks outta 4 and it cruized fine at 35mph, spray was just behind me.;)
I've been watching this thread, and G's got about the Best way of spalin'n this plate issue for newB's
Thanks G;)
Man If I could just get my Sanger and sbc 406 to run anywhere near sm.blk. Mikes, I'd B one Happy Biker, Freak'n Video iz off the hook

WTF, "35mph", you don't even need plates for that, if you want it to run like Mike's boat you have to have "power" and put it to the wood!..:D

[gfinishline]

Nice photo "TOY". Back when you ran that boat, big props were "in vogue", but today we have better prop designs and can downsize the diameters with great top end results. Ron is a great designer, but he did stick too long with the Daytonas with no strakes. From your photo I can see that the tail is dragging a little too much, this could be many factors but may just be too much shaft angle. You do offer insite as to how a 'gull wing' hull may take a solid set, but I bet your power and prop combo are not what this questioner has. I feel his prop my be his major problem, and do you not agree that a smaller diameter prop would be more easily dialed in?

[dry]

http://i291.photobucket.com/albums/ll317/terribletoy/Chargerflat.jpg

Dry, you mentioned a "gull wing" bottom. This 69 Charger ski boat built by Ron Edhe had a concave bottom that was an ellipse that went from about 1/2 inch deep in the center made a gradual curve to about a foot from the chine and then made a sharper drop. It was an early runner attempt. Is the "gull wing" on your boat like that?

Anyway this boat set as you see it the picture taken at Lake Ming. It was an 80 to 90 mph deal with an 11 1/2 X 15 Menkins and 12 gears. The hull had a slight rocker and I set the plate dead flat with the bottom with the right turn buckle down an 1/8 or slightly more. It didn't have pedals, just a handle. I would set the boat with handle at launch and forget it. Don't know if this will help any but thought I would pass it along. Good luck with your boat, I know how frustrating it can be to chase bugs.

Terrible Toy you are right on with the hull configuration, i didn't get to get it wet this weekend but i scrutinized the cav plate heavily, i took a 5' carpenters square and placed against the plate left to right where i could get good solid measurements at one time all the way across. What i found was the center most 2 turnbuckles had the plate when at rest (full up at the pedal stop) 3/8" down and then the next 2 turnbuckles meaning the one on each side of those were 1/4" down and then the next 2 on each side of the last had the plate at a 1/8" down and the outside most turnbuckles had the plate at a 1/16th down drivers side and passengers was 1/4" down..............So what i did was kept the 5' square attached the the cav plate and readjusted all the turnbuckles and pulled the cav plate up all the way across the plate so it was square against the carpenters square all the way across except for the left drivers outside turnbuckle at 1/16" down and the passengers side outermost turnbuckle at 1/8" down and all the levers when looking across the rear from the port side are at about 1:00 a clock...........What does this sound like for a starting point....I found i had been measuring the plate the wrong way prior to this:eek:

[Terrible toy]

Nice photo "TOY". Back when you ran that boat, big props were "in vogue", but today we have better prop designs and can downsize the diameters with great top end results. Ron is a great designer, but he did stick too long with the Daytonas with no strakes. From your photo I can see that the tail is dragging a little too much, this could be many factors but may just be too much shaft angle. You do offer insite as to how a 'gull wing' hull may take a solid set, but I bet your power and prop combo are not what this questioner has. I feel his prop my be his major problem, and do you not agree that a smaller diameter prop would be more easily dialed in?

Right on a couple of things George, it was a tail dragger. It was a primarily a ski boat so the engine was back for rear seat room. Of course at that time I was of the young, know everything, really know nothing set and was unaware of things like that.

You're also right on the design, it was a circle boat with no strakes. As I recall a couple of guys ran this hull in SS and SK and did pretty well when the boat first came out.

Probable asking the wrong guy about props, it's been a long time since I was serious about the subject. I do wish I had kept my records from boat racing. I'm sure prop science has changed since 1990 but it might be helpful to some here if I could share all the different props, gears, engine combos, tune ups, etc., I tried. I know the smallest race flat bottom diameter prop I ran was 10 7/8s and the largest was 11 1/2. The very best flat prop was a 11 X 15 Ron Black "variable pitch" deal. Once I got that one I pretty much stuck with it. Maybe today's propellors are more precision but back then you could have a prop duplicated as exact as possible and the performance be different.

The best prop I ran in the hydros was an 11 X 17 Cary. It was a winner like the Black prop and I used it on boats from comp hydro to UGH until it developed a crack in the hub.

Since I normally ran a lower gear and turned my motors tighter then most of my competition it would have been interesting to try your small prop suggestion with a taller gear. It might have loaded the right side a little less.

Do you up the pitch with the new smaller diameter props, or run more gear?

Bill

[Terrible toy]

Terrible Toy you are right on with the hull configuration, i didn't get to get it wet this weekend but i scrutinized the cav plate heavily, i took a 5' carpenters square and placed against the plate left to right where i could get good solid measurements at one time all the way across. What i found was the center most 2 turnbuckles had the plate when at rest (full up at the pedal stop) 3/8" down and then the next 2 turnbuckles meaning the one on each side of those were 1/4" down and then the next 2 on each side of the last had the plate at a 1/8" down and the outside most turnbuckles had the plate at a 1/16th down drivers side and passengers was 1/4" down..............So what i did was kept the 5' square attached the the cav plate and readjusted all the turnbuckles and pulled the cav plate up all the way across the plate so it was square against the carpenters square all the way across except for the left drivers outside turnbuckle at 1/16" down and the passengers side outermost turnbuckle at 1/8" down and all the levers when looking across the rear from the port side are at about 1:00 a clock...........What does this sound like for a starting point....I found i had been measuring the plate the wrong way prior to this:eek:

You may have just solved your problems. 3/8" down in the center is a ton. The only thing I might add before you try it is to take out the 1/6" down on the drivers side, that's just drag you don't need.

[dry]

Ok i will take out the 1/16" down on the drivers side before going back out this weekend!
Thanks

[gfinishline]

"Pitch or gear?" It depends on the motor/boat/control. Most blown deals get more gear, so as not to 'upset" the control. I've even used the 90 degree full radius cup on drag two blades with great success. "Three percent gear changes are more accurate than a truck bed full of 16 or 17 pitch props". RIGHT?

[gfinishline]

Good to see that you are actually realizing what we are telling you. (and correcting as you go along) The previous owners of many of the boats you guys have here now, had no idea what they were doing. They purchased "Joe Blow's old race boat" and IT RUNS GREAT! For all the rest of us, this "give and take" about what to LOOK FOR, is worth money in the bank. But only if you follow directions and report your results. I can not remember any two hulls out of the same molds, being exactly alike, so too will be your own personal "tweeks" to get your boat correct for your own demands. "party on!"

[hm66Howard]

against the plate left to right where i could get good solid measurements at one time all the way across. Now I'm confused. :confused: You gauged your plate from left to right? I thought we were supposed to gauge it to the bottom of the hull then, check it side to side to see if there the same. Am I missing something here?

[dry]

Ok, maybe i didn't explain it right 1st i took a 5' carpenters square and laid it across the plate "left to right" by doing this i could see what i needed to do, to bring the plate up or down at each point to at least start with the plate squared up from left to right meaning all turnbuckles holding the plate have been adjusted so the plate and c-square are square. Then once the plate was squared up with the carpenters square i took the c-square and placed it on the bottom of the boat 24 inches back from the transom and held the c-square flush to hull in front of each turnbuckle and measured the distance between the bottom of plate and c-square at each turnbuckle point of attachment across the plate and then adjusted each turnbuckle accordingly so i had the same distance between the bottom of plate and top of c-square.

Is this not accomplishing the same thing????

[FC-Pilot]

I usually just go off of the bottom of the boat (like you said holding the strait edge 24" under the boat) and use that as my reference. The bottom of my boat is strait enough that going from left to right I don't see much of an issue in the plate being flat. I just keep all my notes based off of the measurements from the bottom of the boat measurement.

Paul

[gfinishline]

Ok, maybe i didn't explain it right 1st i took a 5' carpenters square and laid it across the plate "left to right" by doing this i could see what i needed to do, to bring the plate up or down at each point to at least start with the plate squared up from left to right meaning all turnbuckles holding the plate have been adjusted so the plate and c-square are square. Then once the plate was squared up with the carpenters square i took the c-square and placed it on the bottom of the boat 24 inches back from the transom and held the c-square flush to hull in front of each turnbuckle and measured the distance between the bottom of plate and c-square at each turnbuckle point of attachment across the plate and then adjusted each turnbuckle accordingly so i had the same distance between the bottom of plate and top of c-square.

Is this not accomplishing the same thing????

Please go back to the "5' square"! Place it (front to rear) along the bottom of the hull and to the ends of the plates. You will be compairing the 9" behind the boat (plates only) with the 51" of hull bottom with plates attached. Do the front to rear measurement about 8 times (evenly spaced) across the rear of your boat. Your hand/foot controls should be in their TOP UP position durring this. Make the trailing edge of the plates 1/8" UP from level, (the striking end of a matchbook thick) all the way across except for the last (only one) outside right end turnbuckle. The plate at the right outside end should be level with the bottom. (even with the square at it's end) Flat to the bottom of the hull. This is where I would start. Don't worry too much about "left to right" at this point!

[SonnyGlide]

I drop'd N 2 locks when she was rolling a little, she smothed out and I left'em there, I was enjoying the ride.
drop in .10$ behing the coupler will cure this? 10.75X15 18 gears.

as far as the power, I have an Honest 600+hp sbc, I'll stab Her when I get comfortable:rolleyes:
the 35mi. was for a motor shake down, and just a nice cruze, just my 2nd time in the boat, and I did C 50mph on the gps.
I'll get there :D

[dry]

Please go back to the "5' square"! Place it (front to rear) along the bottom of the hull and to the ends of the plates. You will be compairing the 9" behind the boat (plates only) with the 51" of hull bottom with plates attached. Do the front to rear measurement about 8 times (evenly spaced) across the rear of your boat. Your hand/foot controls should be in their TOP UP position durring this. Make the trailing edge of the plates 1/8" UP from level, (the striking end of a matchbook thick) all the way across except for the last (only one) outside right end turnbuckle. The plate at the right outside end should be level with the bottom. (even with the square at it's end) Flat to the bottom of the hull. This is where I would start. Don't worry too much about "left to right" at this point!

I appreciate the advice and i have reset the plate this weekend it was rainy, so didnot get to get her out......The plate is definately now set all the way across at 1/8" up from even with the hull at all 8 points where the turnbuckles meet the plate. It was measured and remeasured and set with feeler gauge........I will let you know what happens:)

[gfinishline]

Please look at my post 6th line from top; "except for the last (one only) outside right end turnbuckle". You want that ONE at LEVEL with the hull bottom (front to rear) So the plate "turns down/level on the right end" only. At this "released plate setting" your boat may feel very loose as to it's previous adjustments. Just release the down foot control SLOWLY as you "get the feel" for the boat.

[dry]

Please look at my post 6th line from top; "except for the last (one only) outside right end turnbuckle". You want that ONE at LEVEL with the hull bottom (front to rear) So the plate "turns down/level on the right end" only. At this "released plate setting" your boat may feel very loose as to it's previous adjustments. Just release the down foot control SLOWLY as you "get the feel" for the boat.

Ok, I will level the right corner...........I just figured what the hell i will raise all of them the same. You guys know way more than i ever will so i will level the far right one.........:)

[gfinishline]

"I agree" BUT, some is 'better' and more may be deadly. This 'plate setting' is THE BASELINE, and you will 'tune' for your own FEEL. Go safe, go fast, go often!

[babyhydro]

I have been reading the posts, has anybody tried lifting the plates and tring to run thru the porposing? I have a hallet and it will porpois,but as long as I stay into it it will go thru it, just a thought, I have had numerous flats some I couldnt get to take a set some I could, Iam in the process of rigging a cole tr-2, and they are a lot easier to set and of coarse a hydro just stab it and hang on but will not run in any kind of rough conditions.:

[Terrible toy]

I appreciate the advice and i have reset the plate this weekend it was rainy, so didnot get to get her out......The plate is definately now set all the way across at 1/8" up from even with the hull at all 8 points where the turnbuckles meet the plate. It was measured and remeasured and set with feeler gauge........I will let you know what happens:)

Dry, I was in the same place you are with my Charger I mentioned earlier, new to fast flats. I said that the plate was dead flat with the bottom except for the right turn buckle. Well, being a new to flats I set them the way Dick Rossberg, the shop foreman at Charger, told me to. For what it was it ran fairly well.

Years later when I started racing on a more serious level I tried to do some testing with different plate settings. I wanted to try different settings in different water and wind conditions. The reality of racing is that you rarely got more then two qualifying passes and you wanted to get in the show with one. So, I tried a few different settings getting as high as 3/8" up. However, I can't remember ever having a different setting then 1/8" up for eliminations.

The reason I mention this is that Rossberg was very knowledgeable and I wonder if the setting he suggested was because of the unusual bottom shape that your boat and my Charger had.:confused: Don't forget to drop that right turnbuckle down a touch like gfinishline suggested.

[RiverRacer]

I have a hallet and it will porpois,but as long as I stay into it it will go thru it

That's normal, at part throttle there is not enough power applied to hold it on a set, but if the boat is set up right it holds a set on full power!...

[babyhydro]

From what I understand the reason for the porposing is a speed the boat is tring to pack air and balance at the same time, if there is not enough speed the air escapes from the bottom of the boat and then the process begins again, of coarse this is why its more difficult for a true flat to take a set and the balance factor and the placement of the prop, but if you increase down plate your keeping the bottom wet and fighting the boat tring to lift, with a runner you have let wetted area at speed and is able to pack air better and keep it between the runners, just my opinion but I could be wrong.

[Terrible toy]

From what I understand the reason for the porposing is a speed the boat is tring to pack air and balance at the same time, if there is not enough speed the air escapes from the bottom of the boat and then the process begins again, of coarse this is why its more difficult for a true flat to take a set and the balance factor and the placement of the prop, but if you increase down plate your keeping the bottom wet and fighting the boat tring to lift, with a runner you have let wetted area at speed and is able to pack air better and keep it between the runners, just my opinion but I could be wrong.

Good subject for debate. To compare apples to apples and oranges to oranges, lets take a "lake" boat and lightweight drag boat and look at them separately. The lake boat has a 500 hp big block, 650 lb hull, true flatbottom, engine back and strut forward and at a steeper shaft angle then the race hull. This example could theoretically run 87 mph. The runner bottom race boat (say a 1981 Hondo T deck) has a 470 inch motor putting out 930 hp, hull weighs just over 300 lbs, and has a 7° strut. This boat would run 130.87 mph..

To go fast both boats use applied horse power to overcome drag (wetted area, prop/strut/shaft, rudder and the wind resistance of the boat, driver cross sectional area). Of course, the race boat has the power, light weight and balance to drive the boat out of the water and quickly get on a set. My laymens definition of a set is when the boat is at the point of least wetted area and optimum ride attitude. Also, it has the least wave formation at the forward hull/water contact point. All boats from drag boats to tug boats form waves as they go through the water. Another factor that is a little misunderstood by some is the lift caused by air acting on the hull. Just like an airplane taking off boats don't get appreciable air pressure lift until well down track. The runner bottom hulls, in addition to having less wetted area, bleeds some air pressure out the back at high speed. They then don't need to use as much drag causing inputs like plate, strut angle, etc. to hold the nose down.

Getting back to the wave formation concept. I think this is a dynamic that has significant influence on the performance of boats. Here is what I think happens (notice I said think happens). The race boat, like mentioned above, drives itself out of the water and gets on top and if plated correctly forms a very small wave. You can see this in photos of well set up drag boats that show very little, if any, spray off the chines. Our lake boat example would, on the other hand, have spray coming off the chines well in front of the strut. This would indicate a larger wave at the front of the wetted area. If our little lake boat is fairly well balanced the increasing plate effectiveness would balance the air pressure and the whole thing would get through a speed run (at 87 mph) maintaining a constant attitude. If the boat wasn't as was well balanced or was getting weird plate movements by the driver it might climb up the wave and then fall off the back and then repeat again into a porpoise. The term cracker box comes to mind as an example.:D

Hope this opens up a discussion because I would like to hear your thoughts and ideas on the subject.

[ABBOTTCRAFT]

Interesting thoughts...I'm still likin' the more HP you put to it, the less of those problems you have to contend with... Sometimes Brute force will fix a lot of technical problems...Notice I said SOMETIMES.......

[gfinishline]

I see what you are saying and I must add that 'flat bottoms' force the air out and around the chines, where 'runner bottoms' allow some of the air pressure to be "rolled under the hull' and control the air to a limited amount. Most flat bottoms ARE FLAT at the transom, this really makes them difficult to modify into "air/water controlers". Just remember that water is (aprox) 300 times more dense than air, so "us boat guys look at water", and don't really think about air much. "How you use the air, effects how the water flows around your hull".(at higher speeds) In the past, I have studied how "shaft angles" overcame hull drag, but I don't see it as "powerlift VS drag". I see it like "skipping stones" on a lake. "The correct thrust angle/ and lift for the gross mass". "Along with the control of water and air drag being done by the rudder only". If any of you went to the 'bracket races' in Bullhead City back in the 1980's you saw a boat with a "nose wing". The cross winds there were heavy and we tried to make a wing that would correct our problem. It was mounted under the cap, and above the bow eye. It was 'foot controled' and about 18" wide. It did control the nose in the wind, but it cost too much to offer it to the public. "No body would believe it actually worked" "Getting a set seems easy now".

[Carnivalride]

Interesting thoughts...I'm still likin' the more HP you put to it, the less of those problems you have to contend with... Sometimes Brute force will fix a lot of technical problems...Notice I said SOMETIMES.......


LMAO, I like the more HP method better myself too but I had to make my boat more effecient. Couldn't afford to do more to the engine but had time and some skills so I changed the bottom some and reset the hardware with some well given advice. I do have to say it is a much nicer riding/driving boat after the work. The speed and ET was what I was going for but the side effect of the handling shows even when your just out playing. Getting one set up right is time well spent IMO no matter what power level your at.

[ABBOTTCRAFT]

I hear ya'.. I know you have pics somewhere..:D

[gfinishline]

"You're welcome Loren" I'm happy that you can feel the difference. I wish I could help with some selection of props to test, but I sold them all. Often more horsepower brings more problems too. Just depends on where you are at and what you have.

[Carnivalride]

"You're welcome Loren" I'm happy that you can feel the difference. I wish I could help with some selection of props to test, but I sold them all. Often more horsepower brings more problems too. Just depends on where you are at and what you have.

Yep george you helped me get it straightened out pretty well. Honestly though this year I've worked so much OT and chased my kids so much it hasn't even made it out yet. :( Prop changes were next on the list but as you can see I just haven't made any progress. Took it apart to inspect the engine after last year and spot a few blemishes in the paint. Long story short I should have left it together. LOL Oh well The engines together and I just have to wet sand and buff out the two touch up spots and it can go back together. More pics of the induction crap that got me side tracked later on......

[gfinishline]

"It's just a ski boat with a bite!"

[dry]

I see what you are saying and I must add that 'flat bottoms' force the air out and around the chines, where 'runner bottoms' allow some of the air pressure to be "rolled under the hull' and control the air to a limited amount. Most flat bottoms ARE FLAT at the transom, this really makes them difficult to modify into "air/water controlers". Just remember that water is (aprox) 300 times more dense than air, so "us boat guys look at water", and don't really think about air much. "How you use the air, effects how the water flows around your hull".(at higher speeds) In the past, I have studied how "shaft angles" overcame hull drag, but I don't see it as "powerlift VS drag". I see it like "skipping stones" on a lake.

Ok, then with this being said in the above quote, where does the Gull Style Bottom come into play? Is is the step between a flat bottom and runner bottom? It appears this style would pack air as well if not better than a runner bottom, Yes? Be easy on me just trying to learn!:confused:

[babyhydro]

Iam getting ready to try the more horsepower thing, I have a 69 hallet that I put a 468 blower motor in to break in while I get the cole done, with the mild 454 it took a set with the plates raised all the way up with only a lockout it but you have to stay into the throttle until it stops porposing also we had a 66 hallet mild 427 12 degree that would also take a set.

[Carnivalride]

"It's just a ski boat with a bite!"

Hey now it's only 'bit' a few :D

How much "bite" can it have it's only a heavy old hondo with an all iron 454 so like the signature line says "It's just a ski boat with bark" ;)

[Terrible toy]

Ok, then with this being said in the above quote, where does the Gull Style Bottom come into play? Is is the step between a flat bottom and runner bottom? It appears this style would pack air as well if not better than a runner bottom, Yes? Be easy on me just trying to learn!:confused:

A stage between flat and runner is exactly what the "hollow" bottom design was. I have no idea who gets credit for designing the runner bottom. My guess is it's one or more of the following. Ron Ehde, Howard Brown, Irv Brendel, or maybe Jack Davidsion. I'm sure Harlan Orrin or others here know much more then I do about the history of the drag boat hull.:cool:

[babyhydro]

First, how do you start a new post? cant figure it out, I would like to know what all is involved in converting a powerglide for use in a boat? would like to put one in the hallet for Idlezones, I know about removing the converter but what about coupling it to the v-drive?

[SnoC653]

First, how do you start a new post? cant figure it out, I would like to know what all is involved in converting a powerglide for use in a boat? would like to put one in the hallet for Idlezones, I know about removing the converter but what about coupling it to the v-drive?

You go to the main forums page. Click on Engines and transmissions. Then at the top you click the new topic button and title it something like powerglide conversion and post your qestion in the body of the post.