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OK, for those of you who are dying to start making some turn fins, here is the correct aluminum. The best aluminum that we have found which will hold shape and also bend easily is 2024. You can buy it at http://mcmaster.com The various sizes are on page 3501 of the catalog. I use .063 for 21 and 45 boats and .125 for 67 and up. I would bet that you could use something in between instead of the .125" stuff. They have sizes of .080", .090", .100" which fall in between these sizes. we tried 7075 and it did not bend well and 6061 was too soft.
I will promise you that effort spent with turn fins will reward you about as much as anything that you can do.

Marty Davis
How about some starting points on fins. Lets get some involvement.

1. The cup at the bottom of the fin. Why?

2. How far into the water should the cup start?

3. Where in relation to the cg should the fin be mounted?

4.. How deep or wide must the fin be?

5. Should you sharpen only the right side of the leading edge or equally on both sides?

6. Why does the fin leading edge need to be raked back?

7. Why is the rear trailing edge raked back?

8. Should the fin be parallel to the tub?

Any takers?
John, I will wait for your answers. I want to see if you remember what I told you.

Marten Davis once said: "Don Pinckert knows more about skid fins than anybody in model boating".

dp
 
Ok Don.......First off, about less dihedral more drag way back on this post. I'm wrong on that one. Must have had too much sex the night before. You could have jumped in but you didn't. Thanks. We all make mistakes. Now, the turn fin. When I talk with you it's like coming up to the wise man on top of the hill. You speak in riddles and wait for me to guess the correct answer. I'm the little grasshoper. You are the Master. You still have not told me the answer. You did tell me the angle of the water leaving the fin is very important. I played with that. Question number 7 is asking that same question. There is no one I know of that can answer that question but you. Marty said the less water off the fin, the better. I am tending to believe lots of water off the fin is good, if you use it wisely. How else can you keep a boat from rolling over in a 100 mph turn? That is why I put that question in there. I'm glad to see you posting. You are the one person in all of model boating that has the most qualifications to answer all of these questions. Like I said...you are like the wise man on top of the hill. Speak.
 
View attachment 6312
what would the difference of the dead rise angle of the sponson template riding surface on the left do vs the one on the right, would a steeper angle contribute to higer speeds? or if the angle is lower would the boat run faster and handle better? what would be the best compromise take a look at the templates am working with. what are your thougths anybody
Hi Leighton, You can do all of this for yourself. Do like I did back in the 1960's. ---- Cut out some different sponson bottoms, coat them with c.a., use contact cement to stick different ones to the boat. ---- lacquer thinner will remove the contact cement instantly. ---- Contact cement is not waterproof, but, it will do what you want.

You will find wider and flatter run faster. How fast and clean do you want to run?? If you go too wide and flat, you won't be able to keep the sponsons on the water they will run so clean.

Don't take my word for it.

DO IT FOR YOURSELF -- THEN YOU WILL KNOW.

John Finch, had his boat upside down. I did the same thing one time. ---- I offset the strut on a boat upside down, turned it over and it was on the wrong side. ---- Well, Duh.

Don Pinckert
 
Don,

So give us all a hint on the turn fin. We know that for every action there is a reaction. Water going up must push down on the device pushing the water up. Right or wrong? I designed a cat hull once. It was ugly, I admit. When the boat came out of the mold the sponsons sucked inward like fiberglass does at corners. You know what I am talking about there. Well, that took an inside sponson edge that was designed for a two degree cant outward to a two degree inward cant. The boat would rip down the straightaway and when it went into the turn the right sponson cut into the water on the inside edge and actually screwed the boat into the water so hard that the boat would go under water like a submarine. That was only two degrees. Same principle as the turn fin?

All the boats out of the mold did that. It took a lot of head scratching to figure that one out. We fixed the inward cant and the boat worked great after that. It was still ugly though. Thoughts?
 
View attachment 6312
what would the difference of the dead rise angle of the sponson template riding surface on the left do vs the one on the right, would a steeper angle contribute to higer speeds? or if the angle is lower would the boat run faster and handle better? what would be the best compromise take a look at the templates am working with. what are your thougths anybody
The left flatter deadrise will have more contact with the water and cause more pull on that side of the boat. If you used the flat one on the left side of the boat and the more angled one on the right side of the boat it would help prevent propwalk as the left one would drag more, thus making the boat veer to the left. which compensates for propwalk wanting to make the boat turn right. You can make too much deadrise on the left sponson and boat will dig and not turn well. I prefere a 2 to 3 degree deadrise on the right sponson and a 1 to 2 degree deadrise on the left. The outsides of the sponsons determine how much slide the boat will have when cornering. Flat sides or too much straight up and down angles will make the boat trip and roll over when cornering. Too much angle will let the boat slide too much. The weight and speed of the boat has a lot to do with the angle you choose there.


John:

Interesting analysis.....

It seems that this is a perfect example to show that there are many ways to accomplish something.

First let's define Deadrise: What is deadrise? It's the angle of the boat's bottom (sponsons for an outrigger) relative to the horizontal. A flat bottom boat has a deadrise of 0°, while a deep-V might have a deadrise of 25°.

I do almost the opposite as what you have described. I keep the right sponson flat and the left with 1 degree of dihedral (for racing). The reason is that when the boat slows or goes into the turn, the sponson with the dihedral will penetrate more than the one that has a flat bottom. This penetration creates drag. I don't want more drag on the right sponson since that is the one that gets the pressure from prop torque. On most hydros in the SAW, the sponsons do not penetrate at all because of the speed and attack angle of the sponson. They are effectively only running on a TINY amount of sponson bottom anyway. Once you slow down or reduce the engine speed the prop does not press as hard on the sponson. Once you get back on the throttle, the prop forces the sponson to try to penetrate the water and you get some torque.

Another factor that must be put into the equation is the rudder location. IF the rudder is on the left, any right turn will reduce weight on the left front sponson and add weight to the right (can cause blow off). For a rudder on the right the opposite. The rudder location on an outrigger with wide sponson spacing really does not make a huge amount of difference because of the wide lever arm of the wide sponson stance.

I agree with you about the negative of having a lot of dihedral on the left sponson. It does make the sponson penetrate and you get terrible turning, darting or hooking.

One thing that is very interesting is the width of sponsons on various outriggers. On Stu's Crapshooters, he uses the narrowest sponsons that I have seen. Have you noticed how wet the boat is at launch. That is the reason. He gets a BIG advantage after the boat is up on top of the water with the narrower sponsons because he has much less drag and the smaller sponsons punch a very small hole in the air. As a comparison, the Roadrunner type boat uses a much wider run surface, gets up easily at launch and then pays a penalty with drag and hole punching. Another advantage is that you can run slightly more attack angle on the sponsons because of the narrow running surface (maybe .2 degree or so). That makes a VERY BIG speed difference because of reduced drag. I ran one of his 67 boats for a season and found out about the narrow sponson advantages. I probably would never have figured that out if I hadn't run it that season. In the past I had always run on the wide side.

For SAW, high dihedral is a huge advantage because it allows the air to spill out from under the sponson as well as reduce the contact area at speed. It also is good for turning for SAW since the dihedral will act like a turn fin at very low speeds. You can actually run WITHOUT a fin with 5 degrees of dihedral at slow turn speeds.

Much cool stuff at play with hydrodynamics on an outrigger. :)

Marty Davis
Marten, My Boy, You have just set sponson design back to the 1960's. This narrow, less drag going faster was the standard way of thinking when I started boating. ---- "Dopey Thinking".

Before I got into boating, I had spent twenty years flying airplanes. Lower wing loading flies faster, manuevers better, turns faster. I looked at the small planing surfaces and related.

I immediately started setting records that were deemed 'impossible' by the days standards. How did I do it???? ---- It was easy. I took a fiberglass boat called the Li'l Hoss, went from 1-3/4" surface to 3" surface. ---- The boat went from "clawing" to "skimming" across the water.

CRAPSHOOTER ---- In the fall of 1973, Charlie Sweet called me from Detroit. He and Tim Ries, had been laid off from Chrysler. They needed Xmas money. He asked if I minded if they took my Li'l Mixer kit and used it for a planform to build some boats? I told him it was fine with me. That is the boat and Crapshooter Company you later acquired and started producing. ---- Now, what did they do? ---- They MODIFIED it. ---- The Li'l Mixer was 32" long. Hull was 6" wide. Planing surface was 3". ---- They cut to hull width down to about 4", cut the planing surface to 2". ---- Then 'busted' their butts running new shnuerle port engines trying to break my old five year old records with side port K&B's. ---- Well, Duh !! ---- They had taken too much air from under the hull and 'firmly planted' those narrow 'high drag' sponsons on the water.

How does Stu, hear with his hippockets over his ears? ---- Skinny Minnie hulls and Skinny Minnie sponsons may be nice and water hugging stable, BUT, it 'ain't the way to go FAST.

On one hand you say flatter for speed, then you want to run 5 degree "High Dihedral" sponsons on a straightaway boat. ---- I don't know whether that is "Double Whammy" thinking or "Double Duh" thinking. ----

Now, Can you run too flat and too much planing surface on a heat racing boat? ---- You sure can.

Just read my next letter on the ROADRUNNER. Boy, do you have your hip pockets over your ears on that boat. ---- Remember, it started as a Coyote ---- MODIFIED.

to be continued ------------------- Don Pinckert
 
View attachment 6312
what would the difference of the dead rise angle of the sponson template riding surface on the left do vs the one on the right, would a steeper angle contribute to higer speeds? or if the angle is lower would the boat run faster and handle better? what would be the best compromise take a look at the templates am working with. what are your thougths anybody
The left flatter deadrise will have more contact with the water and cause more pull on that side of the boat. If you used the flat one on the left side of the boat and the more angled one on the right side of the boat it would help prevent propwalk as the left one would drag more, thus making the boat veer to the left. which compensates for propwalk wanting to make the boat turn right. You can make too much deadrise on the left sponson and boat will dig and not turn well. I prefere a 2 to 3 degree deadrise on the right sponson and a 1 to 2 degree deadrise on the left. The outsides of the sponsons determine how much slide the boat will have when cornering. Flat sides or too much straight up and down angles will make the boat trip and roll over when cornering. Too much angle will let the boat slide too much. The weight and speed of the boat has a lot to do with the angle you choose there.


John:

Interesting analysis.....

It seems that this is a perfect example to show that there are many ways to accomplish something.

First let's define Deadrise: What is deadrise? It's the angle of the boat's bottom (sponsons for an outrigger) relative to the horizontal. A flat bottom boat has a deadrise of 0°, while a deep-V might have a deadrise of 25°.

I do almost the opposite as what you have described. I keep the right sponson flat and the left with 1 degree of dihedral (for racing). The reason is that when the boat slows or goes into the turn, the sponson with the dihedral will penetrate more than the one that has a flat bottom. This penetration creates drag. I don't want more drag on the right sponson since that is the one that gets the pressure from prop torque. On most hydros in the SAW, the sponsons do not penetrate at all because of the speed and attack angle of the sponson. They are effectively only running on a TINY amount of sponson bottom anyway. Once you slow down or reduce the engine speed the prop does not press as hard on the sponson. Once you get back on the throttle, the prop forces the sponson to try to penetrate the water and you get some torque.

Another factor that must be put into the equation is the rudder location. IF the rudder is on the left, any right turn will reduce weight on the left front sponson and add weight to the right (can cause blow off). For a rudder on the right the opposite. The rudder location on an outrigger with wide sponson spacing really does not make a huge amount of difference because of the wide lever arm of the wide sponson stance.

I agree with you about the negative of having a lot of dihedral on the left sponson. It does make the sponson penetrate and you get terrible turning, darting or hooking.

One thing that is very interesting is the width of sponsons on various outriggers. On Stu's Crapshooters, he uses the narrowest sponsons that I have seen. Have you noticed how wet the boat is at launch. That is the reason. He gets a BIG advantage after the boat is up on top of the water with the narrower sponsons because he has much less drag and the smaller sponsons punch a very small hole in the air. As a comparison, the Roadrunner type boat uses a much wider run surface, gets up easily at launch and then pays a penalty with drag and hole punching. Another advantage is that you can run slightly more attack angle on the sponsons because of the narrow running surface (maybe .2 degree or so). That makes a VERY BIG speed difference because of reduced drag. I ran one of his 67 boats for a season and found out about the narrow sponson advantages. I probably would never have figured that out if I hadn't run it that season. In the past I had always run on the wide side.

For SAW, high dihedral is a huge advantage because it allows the air to spill out from under the sponson as well as reduce the contact area at speed. It also is good for turning for SAW since the dihedral will act like a turn fin at very low speeds. You can actually run WITHOUT a fin with 5 degrees of dihedral at slow turn speeds.

Much cool stuff at play with hydrodynamics on an outrigger. :)

Marty Davis
Marten, My Boy, You have just set sponson design back to the 1960's. This narrow, less drag going faster was the standard way of thinking when I started boating. ---- "Dopey Thinking".

Before I got into boating, I had spent twenty years flying airplanes. Lower wing loading flies faster, manuevers better, turns faster. I looked at the small planing surfaces and related.

I immediately started setting records that were deemed 'impossible' by the days standards. How did I do it???? ---- It was easy. I took a fiberglass boat called the Li'l Hoss, went from 1-3/4" surface to 3" surface. ---- The boat went from "clawing" to "skimming" across the water.

CRAPSHOOTER ---- In the fall of 1973, Charlie Sweet called me from Detroit. He and Tim Ries, had been laid off from Chrysler. They needed Xmas money. He asked if I minded if they took my Li'l Mixer kit and used it for a planform to build some boats? I told him it was fine with me. That is the boat and Crapshooter Company you later acquired and started producing. ---- Now, what did they do? ---- They MODIFIED it. ---- The Li'l Mixer was 32" long. Hull was 6" wide. Planing surface was 3". ---- They cut to hull width down to about 4", cut the planing surface to 2". ---- Then 'busted' their butts running new shnuerle port engines trying to break my old five year old records with side port K&B's. ---- Well, Duh !! ---- They had taken too much air from under the hull and 'firmly planted' those narrow 'high drag' sponsons on the water.

How does Stu, hear with his hippockets over his ears? ---- Skinny Minnie hulls and Skinny Minnie sponsons may be nice and water hugging stable, BUT, it 'ain't the way to go FAST.

On one hand you say flatter for speed, then you want to run 5 degree "High Dihedral" sponsons on a straightaway boat. ---- I don't know whether that is "Double Whammy" thinking or "Double Duh" thinking. ----

Now, Can you run too flat and too much planing surface on a heat racing boat? ---- You sure can.

Just read my next letter on the ROADRUNNER. Boy, do you have your hip pockets over your ears on that boat. ---- Remember, it started as a Coyote ---- MODIFIED.

to be continued ------------------- Don Pinckert
Don:

If you are going to quote me, at least be accurate.....

Did I say that Stu's approach was mine - NO. I just said it is interesting and effective. Before the Internats in Sarasota he and I were testing and getting ready for SAW Trophy Trials. The 60 boat that I was running (a heat race boat) was running 99mph. I would say that it was a dominant speed for Trophy Trials for a Heat Race boat, so your analogy about going fast with narrow sponsons might not be accurate. I presented my approach and looked at Stu's approach saying only that it was interesting. I was running one of Stu's own personal boats and enjoyed it. It was a boat that was dominant. My approach has always been to use a flat right sponson and 1 degree on the left with wide running surfaces. Did you miss this statement: "when the boat slows or goes into the turn, the sponson with the dihedral will penetrate more than the one that has a flat bottom. This penetration creates drag."

The dihedral discussion was only to point out that it was possible to use dihedral as a turn fin for SAW. 5 degrees allowed you to not run a turn fin at all. I ran VERY wide 5 degree sponsons with increasing dihedral as it moved toward the tips of the sponsons. Actually the dihedral increased to 15 degrees at the tip. The increasing dihedral was only to allow the air to vent out the sides and not stay packed under the sponsons.

Boat design has evolved since the 1960's and some of the things that were done back then have been proven to be NOT the most efficient approach.

Not sure I understand your statement

"Just read my next letter on the ROADRUNNER. Boy, do you have your hip pockets over your ears on that boat. ---- Remember, it started as a Coyote ---- MODIFIED."

You surely can't be talking to me. I did not design the Roadrunner, but I did have something to do with refining it and making it turn. I only ran Roadrunners for a couple years, mostly have run my own design.

Please provide some of your immense expertise, but please also be specific as John and I have done. We are trying to provide details to others so that they will seek out the "Why's" of model boating. The thread started by stating that both of us have used totally different approaches to timed oval and heat racing - results being similar. We pointed out that there were several ways of reaching a goal.

Please provide some specifics so that we can have a discussion..... I have no problem saying that I will try a new approach if I see merit in it, and I am positive that John feels the same way.

Marty Davis
 
Last edited by a moderator:
View attachment 6312
what would the difference of the dead rise angle of the sponson template riding surface on the left do vs the one on the right, would a steeper angle contribute to higer speeds? or if the angle is lower would the boat run faster and handle better? what would be the best compromise take a look at the templates am working with. what are your thougths anybody
The left flatter deadrise will have more contact with the water and cause more pull on that side of the boat. If you used the flat one on the left side of the boat and the more angled one on the right side of the boat it would help prevent propwalk as the left one would drag more, thus making the boat veer to the left. which compensates for propwalk wanting to make the boat turn right. You can make too much deadrise on the left sponson and boat will dig and not turn well. I prefere a 2 to 3 degree deadrise on the right sponson and a 1 to 2 degree deadrise on the left. The outsides of the sponsons determine how much slide the boat will have when cornering. Flat sides or too much straight up and down angles will make the boat trip and roll over when cornering. Too much angle will let the boat slide too much. The weight and speed of the boat has a lot to do with the angle you choose there.


John:

Interesting analysis.....

It seems that this is a perfect example to show that there are many ways to accomplish something.

First let's define Deadrise: What is deadrise? It's the angle of the boat's bottom (sponsons for an outrigger) relative to the horizontal. A flat bottom boat has a deadrise of 0°, while a deep-V might have a deadrise of 25°.

I do almost the opposite as what you have described. I keep the right sponson flat and the left with 1 degree of dihedral (for racing). The reason is that when the boat slows or goes into the turn, the sponson with the dihedral will penetrate more than the one that has a flat bottom. This penetration creates drag. I don't want more drag on the right sponson since that is the one that gets the pressure from prop torque. On most hydros in the SAW, the sponsons do not penetrate at all because of the speed and attack angle of the sponson. They are effectively only running on a TINY amount of sponson bottom anyway. Once you slow down or reduce the engine speed the prop does not press as hard on the sponson. Once you get back on the throttle, the prop forces the sponson to try to penetrate the water and you get some torque.

Another factor that must be put into the equation is the rudder location. IF the rudder is on the left, any right turn will reduce weight on the left front sponson and add weight to the right (can cause blow off). For a rudder on the right the opposite. The rudder location on an outrigger with wide sponson spacing really does not make a huge amount of difference because of the wide lever arm of the wide sponson stance.

I agree with you about the negative of having a lot of dihedral on the left sponson. It does make the sponson penetrate and you get terrible turning, darting or hooking.

One thing that is very interesting is the width of sponsons on various outriggers. On Stu's Crapshooters, he uses the narrowest sponsons that I have seen. Have you noticed how wet the boat is at launch. That is the reason. He gets a BIG advantage after the boat is up on top of the water with the narrower sponsons because he has much less drag and the smaller sponsons punch a very small hole in the air. As a comparison, the Roadrunner type boat uses a much wider run surface, gets up easily at launch and then pays a penalty with drag and hole punching. Another advantage is that you can run slightly more attack angle on the sponsons because of the narrow running surface (maybe .2 degree or so). That makes a VERY BIG speed difference because of reduced drag. I ran one of his 67 boats for a season and found out about the narrow sponson advantages. I probably would never have figured that out if I hadn't run it that season. In the past I had always run on the wide side.

For SAW, high dihedral is a huge advantage because it allows the air to spill out from under the sponson as well as reduce the contact area at speed. It also is good for turning for SAW since the dihedral will act like a turn fin at very low speeds. You can actually run WITHOUT a fin with 5 degrees of dihedral at slow turn speeds.

Much cool stuff at play with hydrodynamics on an outrigger. :)

Marty Davis
Marten, Continued ---- Got my dogs walked, cats fed, baby birds fed, now let's talk about the ROADRUNNER.

Bobby Caudill, bummed around my shop for about two years. I had a new Daytona running for Bobby, that would peel the hide off anything. Coyotes were still dominating the race scene and high points. Bob Francoletti, had the dominating Coyote 65 around. ---- Bobby, would come home from a race laughing how he could just toy with Francoletti. ---- So, why did Bobby get flat Coyote kits and go down the road and copy that boat?? ---- Simple, he knew the Coyote was the boat in demand at the time. ---- Smart move on his part.

So, what did he do to the Coyote? -- He MODIFIED it. Coyote 65, For heat racing, I ran 2-3/4" planing surface with 1/8" dihedral. Made for a nice heat race set-up. Bobby increased the surface to 3" and took out all of the dihedral. As I told him it would, the front sponsons now ran so clean and loose, he couldn't keep them on the water. (Not good for a heat racing boat). I also did not know at that time his devious intentions. He came to me with the problem. ---- I told him the only thing he could do was DROP the rear sponsons so low they would 'literally' DRAG the front sponsons to the water. This became Bobby's FOUR POINT revolutionary concept. (I almost puked at that). He also reduced my angle of attack. Now, the boat just 'plowed' around the lake on the front sponsons with the rear sponsons dragging. That is the cause for the speed loss from the Coyote on both the straight and thru the turns.

THAT THERE, MARTEN, is what you see today and blame it on front sponson drag. ---- Duh.

NOW - Anybody can do this. ---- Pull the rear sponsons off, increase the angle of attack from 3/8" in 6" to my original 1/2" in 6" and see what happens.

Nuff' fun for one day. Don Pinckert

I hate to see model boaters screwed up with bad information.
 
View attachment 6312
what would the difference of the dead rise angle of the sponson template riding surface on the left do vs the one on the right, would a steeper angle contribute to higer speeds? or if the angle is lower would the boat run faster and handle better? what would be the best compromise take a look at the templates am working with. what are your thougths anybody
The left flatter deadrise will have more contact with the water and cause more pull on that side of the boat. If you used the flat one on the left side of the boat and the more angled one on the right side of the boat it would help prevent propwalk as the left one would drag more, thus making the boat veer to the left. which compensates for propwalk wanting to make the boat turn right. You can make too much deadrise on the left sponson and boat will dig and not turn well. I prefere a 2 to 3 degree deadrise on the right sponson and a 1 to 2 degree deadrise on the left. The outsides of the sponsons determine how much slide the boat will have when cornering. Flat sides or too much straight up and down angles will make the boat trip and roll over when cornering. Too much angle will let the boat slide too much. The weight and speed of the boat has a lot to do with the angle you choose there.


John:

Interesting analysis.....

It seems that this is a perfect example to show that there are many ways to accomplish something.

First let's define Deadrise: What is deadrise? It's the angle of the boat's bottom (sponsons for an outrigger) relative to the horizontal. A flat bottom boat has a deadrise of 0°, while a deep-V might have a deadrise of 25°.

I do almost the opposite as what you have described. I keep the right sponson flat and the left with 1 degree of dihedral (for racing). The reason is that when the boat slows or goes into the turn, the sponson with the dihedral will penetrate more than the one that has a flat bottom. This penetration creates drag. I don't want more drag on the right sponson since that is the one that gets the pressure from prop torque. On most hydros in the SAW, the sponsons do not penetrate at all because of the speed and attack angle of the sponson. They are effectively only running on a TINY amount of sponson bottom anyway. Once you slow down or reduce the engine speed the prop does not press as hard on the sponson. Once you get back on the throttle, the prop forces the sponson to try to penetrate the water and you get some torque.

Another factor that must be put into the equation is the rudder location. IF the rudder is on the left, any right turn will reduce weight on the left front sponson and add weight to the right (can cause blow off). For a rudder on the right the opposite. The rudder location on an outrigger with wide sponson spacing really does not make a huge amount of difference because of the wide lever arm of the wide sponson stance.

I agree with you about the negative of having a lot of dihedral on the left sponson. It does make the sponson penetrate and you get terrible turning, darting or hooking.

One thing that is very interesting is the width of sponsons on various outriggers. On Stu's Crapshooters, he uses the narrowest sponsons that I have seen. Have you noticed how wet the boat is at launch. That is the reason. He gets a BIG advantage after the boat is up on top of the water with the narrower sponsons because he has much less drag and the smaller sponsons punch a very small hole in the air. As a comparison, the Roadrunner type boat uses a much wider run surface, gets up easily at launch and then pays a penalty with drag and hole punching. Another advantage is that you can run slightly more attack angle on the sponsons because of the narrow running surface (maybe .2 degree or so). That makes a VERY BIG speed difference because of reduced drag. I ran one of his 67 boats for a season and found out about the narrow sponson advantages. I probably would never have figured that out if I hadn't run it that season. In the past I had always run on the wide side.

For SAW, high dihedral is a huge advantage because it allows the air to spill out from under the sponson as well as reduce the contact area at speed. It also is good for turning for SAW since the dihedral will act like a turn fin at very low speeds. You can actually run WITHOUT a fin with 5 degrees of dihedral at slow turn speeds.

Much cool stuff at play with hydrodynamics on an outrigger. :)

Marty Davis
Marten, My Boy, You have just set sponson design back to the 1960's. This narrow, less drag going faster was the standard way of thinking when I started boating. ---- "Dopey Thinking".

Before I got into boating, I had spent twenty years flying airplanes. Lower wing loading flies faster, manuevers better, turns faster. I looked at the small planing surfaces and related.

I immediately started setting records that were deemed 'impossible' by the days standards. How did I do it???? ---- It was easy. I took a fiberglass boat called the Li'l Hoss, went from 1-3/4" surface to 3" surface. ---- The boat went from "clawing" to "skimming" across the water.

CRAPSHOOTER ---- In the fall of 1973, Charlie Sweet called me from Detroit. He and Tim Ries, had been laid off from Chrysler. They needed Xmas money. He asked if I minded if they took my Li'l Mixer kit and used it for a planform to build some boats? I told him it was fine with me. That is the boat and Crapshooter Company you later acquired and started producing. ---- Now, what did they do? ---- They MODIFIED it. ---- The Li'l Mixer was 32" long. Hull was 6" wide. Planing surface was 3". ---- They cut to hull width down to about 4", cut the planing surface to 2". ---- Then 'busted' their butts running new shnuerle port engines trying to break my old five year old records with side port K&B's. ---- Well, Duh !! ---- They had taken too much air from under the hull and 'firmly planted' those narrow 'high drag' sponsons on the water.

How does Stu, hear with his hippockets over his ears? ---- Skinny Minnie hulls and Skinny Minnie sponsons may be nice and water hugging stable, BUT, it 'ain't the way to go FAST.

On one hand you say flatter for speed, then you want to run 5 degree "High Dihedral" sponsons on a straightaway boat. ---- I don't know whether that is "Double Whammy" thinking or "Double Duh" thinking. ----

Now, Can you run too flat and too much planing surface on a heat racing boat? ---- You sure can.

Just read my next letter on the ROADRUNNER. Boy, do you have your hip pockets over your ears on that boat. ---- Remember, it started as a Coyote ---- MODIFIED.

to be continued ------------------- Don Pinckert
Don:

If you are going to quote me, at least be accurate.....

Did I say that Stu's approach was mine - NO. I just said it is interesting and effective. Before the Internats in Sarasota he and I were testing and getting ready for SAW Trophy Trials. The 60 boat that I was running (a heat race boat) was running 99mph. I would say that it was a dominant speed for Trophy Trials for a Heat Race boat, so your analogy about going fast with narrow sponsons might not be accurate. I presented my approach and looked at Stu's approach saying only that it was interesting. I was running one of Stu's own personal boats and enjoyed it. It was a boat that was dominant. My approach has always been to use a flat right sponson and 1 degree on the left with wide running surfaces. Did you miss this statement: "when the boat slows or goes into the turn, the sponson with the dihedral will penetrate more than the one that has a flat bottom. This penetration creates drag."

The dihedral discussion was only to point out that it was possible to use dihedral as a turn fin for SAW. 5 degrees allowed you to not run a turn fin at all. I ran VERY wide 5 degree sponsons with increasing dihedral as it moved toward the tips of the sponsons. Actually the dihedral increased to 15 degrees at the tip. The increasing dihedral was only to allow the air to vent out the sides and not stay packed under the sponsons.

Boat design has evolved since the 1960's and some of the things that were done back then have been proven to be NOT the most efficient approach.

Not sure I understand your statement

"Just read my next letter on the ROADRUNNER. Boy, do you have your hip pockets over your ears on that boat. ---- Remember, it started as a Coyote ---- MODIFIED."

You surely can't be talking to me. I did not design the Roadrunner, but I did have something to do with refining it and making it turn. I only ran Roadrunners for a couple years, mostly have run my own design.

Please provide some of your immense expertise, but please also be specific as John and I have done. We are trying to provide details to others so that they will seek out the "Why's" of model boating. The thread started by stating that both of us have used totally different approaches to timed oval and heat racing - results being similar. We pointed out that there were several ways of reaching a goal.

Please provide some specifics so that we can have a discussion..... I have no problem saying that I will try a new approach if I see merit in it, and I am positive that John feels the same way.

Marty Davis
Marten, Jennifer, was right. She said: "Don't forget, you are talking to a Midwestern Prima Donna". ---- YUP!

My immense expertise?? ---- Well, at one time I had posted the fastest twenty seven (27) times at record trials on the 1/3 oval. Not all were records, since at one trial I would break and re-break my own record. ---- ALL at your expense. You set ONE (1) oval record in your entire boating life. Along with your ONE (1) straight record with the famous Crapshooter.

Marten, don't you know when to shut up?

Don Pinckert
 
View attachment 6312
what would the difference of the dead rise angle of the sponson template riding surface on the left do vs the one on the right, would a steeper angle contribute to higer speeds? or if the angle is lower would the boat run faster and handle better? what would be the best compromise take a look at the templates am working with. what are your thougths anybody
The left flatter deadrise will have more contact with the water and cause more pull on that side of the boat. If you used the flat one on the left side of the boat and the more angled one on the right side of the boat it would help prevent propwalk as the left one would drag more, thus making the boat veer to the left. which compensates for propwalk wanting to make the boat turn right. You can make too much deadrise on the left sponson and boat will dig and not turn well. I prefere a 2 to 3 degree deadrise on the right sponson and a 1 to 2 degree deadrise on the left. The outsides of the sponsons determine how much slide the boat will have when cornering. Flat sides or too much straight up and down angles will make the boat trip and roll over when cornering. Too much angle will let the boat slide too much. The weight and speed of the boat has a lot to do with the angle you choose there.


John:

Interesting analysis.....

It seems that this is a perfect example to show that there are many ways to accomplish something.

First let's define Deadrise: What is deadrise? It's the angle of the boat's bottom (sponsons for an outrigger) relative to the horizontal. A flat bottom boat has a deadrise of 0°, while a deep-V might have a deadrise of 25°.

I do almost the opposite as what you have described. I keep the right sponson flat and the left with 1 degree of dihedral (for racing). The reason is that when the boat slows or goes into the turn, the sponson with the dihedral will penetrate more than the one that has a flat bottom. This penetration creates drag. I don't want more drag on the right sponson since that is the one that gets the pressure from prop torque. On most hydros in the SAW, the sponsons do not penetrate at all because of the speed and attack angle of the sponson. They are effectively only running on a TINY amount of sponson bottom anyway. Once you slow down or reduce the engine speed the prop does not press as hard on the sponson. Once you get back on the throttle, the prop forces the sponson to try to penetrate the water and you get some torque.

Another factor that must be put into the equation is the rudder location. IF the rudder is on the left, any right turn will reduce weight on the left front sponson and add weight to the right (can cause blow off). For a rudder on the right the opposite. The rudder location on an outrigger with wide sponson spacing really does not make a huge amount of difference because of the wide lever arm of the wide sponson stance.

I agree with you about the negative of having a lot of dihedral on the left sponson. It does make the sponson penetrate and you get terrible turning, darting or hooking.

One thing that is very interesting is the width of sponsons on various outriggers. On Stu's Crapshooters, he uses the narrowest sponsons that I have seen. Have you noticed how wet the boat is at launch. That is the reason. He gets a BIG advantage after the boat is up on top of the water with the narrower sponsons because he has much less drag and the smaller sponsons punch a very small hole in the air. As a comparison, the Roadrunner type boat uses a much wider run surface, gets up easily at launch and then pays a penalty with drag and hole punching. Another advantage is that you can run slightly more attack angle on the sponsons because of the narrow running surface (maybe .2 degree or so). That makes a VERY BIG speed difference because of reduced drag. I ran one of his 67 boats for a season and found out about the narrow sponson advantages. I probably would never have figured that out if I hadn't run it that season. In the past I had always run on the wide side.

For SAW, high dihedral is a huge advantage because it allows the air to spill out from under the sponson as well as reduce the contact area at speed. It also is good for turning for SAW since the dihedral will act like a turn fin at very low speeds. You can actually run WITHOUT a fin with 5 degrees of dihedral at slow turn speeds.

Much cool stuff at play with hydrodynamics on an outrigger. :)

Marty Davis
Marten, My Boy, You have just set sponson design back to the 1960's. This narrow, less drag going faster was the standard way of thinking when I started boating. ---- "Dopey Thinking".

Before I got into boating, I had spent twenty years flying airplanes. Lower wing loading flies faster, manuevers better, turns faster. I looked at the small planing surfaces and related.

I immediately started setting records that were deemed 'impossible' by the days standards. How did I do it???? ---- It was easy. I took a fiberglass boat called the Li'l Hoss, went from 1-3/4" surface to 3" surface. ---- The boat went from "clawing" to "skimming" across the water.

CRAPSHOOTER ---- In the fall of 1973, Charlie Sweet called me from Detroit. He and Tim Ries, had been laid off from Chrysler. They needed Xmas money. He asked if I minded if they took my Li'l Mixer kit and used it for a planform to build some boats? I told him it was fine with me. That is the boat and Crapshooter Company you later acquired and started producing. ---- Now, what did they do? ---- They MODIFIED it. ---- The Li'l Mixer was 32" long. Hull was 6" wide. Planing surface was 3". ---- They cut to hull width down to about 4", cut the planing surface to 2". ---- Then 'busted' their butts running new shnuerle port engines trying to break my old five year old records with side port K&B's. ---- Well, Duh !! ---- They had taken too much air from under the hull and 'firmly planted' those narrow 'high drag' sponsons on the water.

How does Stu, hear with his hippockets over his ears? ---- Skinny Minnie hulls and Skinny Minnie sponsons may be nice and water hugging stable, BUT, it 'ain't the way to go FAST.

On one hand you say flatter for speed, then you want to run 5 degree "High Dihedral" sponsons on a straightaway boat. ---- I don't know whether that is "Double Whammy" thinking or "Double Duh" thinking. ----

Now, Can you run too flat and too much planing surface on a heat racing boat? ---- You sure can.

Just read my next letter on the ROADRUNNER. Boy, do you have your hip pockets over your ears on that boat. ---- Remember, it started as a Coyote ---- MODIFIED.

to be continued ------------------- Don Pinckert
Don:

If you are going to quote me, at least be accurate.....

Did I say that Stu's approach was mine - NO. I just said it is interesting and effective. Before the Internats in Sarasota he and I were testing and getting ready for SAW Trophy Trials. The 60 boat that I was running (a heat race boat) was running 99mph. I would say that it was a dominant speed for Trophy Trials for a Heat Race boat, so your analogy about going fast with narrow sponsons might not be accurate. I presented my approach and looked at Stu's approach saying only that it was interesting. I was running one of Stu's own personal boats and enjoyed it. It was a boat that was dominant. My approach has always been to use a flat right sponson and 1 degree on the left with wide running surfaces. Did you miss this statement: "when the boat slows or goes into the turn, the sponson with the dihedral will penetrate more than the one that has a flat bottom. This penetration creates drag."

The dihedral discussion was only to point out that it was possible to use dihedral as a turn fin for SAW. 5 degrees allowed you to not run a turn fin at all. I ran VERY wide 5 degree sponsons with increasing dihedral as it moved toward the tips of the sponsons. Actually the dihedral increased to 15 degrees at the tip. The increasing dihedral was only to allow the air to vent out the sides and not stay packed under the sponsons.

Boat design has evolved since the 1960's and some of the things that were done back then have been proven to be NOT the most efficient approach.

Not sure I understand your statement

"Just read my next letter on the ROADRUNNER. Boy, do you have your hip pockets over your ears on that boat. ---- Remember, it started as a Coyote ---- MODIFIED."

You surely can't be talking to me. I did not design the Roadrunner, but I did have something to do with refining it and making it turn. I only ran Roadrunners for a couple years, mostly have run my own design.

Please provide some of your immense expertise, but please also be specific as John and I have done. We are trying to provide details to others so that they will seek out the "Why's" of model boating. The thread started by stating that both of us have used totally different approaches to timed oval and heat racing - results being similar. We pointed out that there were several ways of reaching a goal.

Please provide some specifics so that we can have a discussion..... I have no problem saying that I will try a new approach if I see merit in it, and I am positive that John feels the same way.

Marty Davis
Marten, Jennifer, was right. She said: "Don't forget, you are talking to a Midwestern Prima Donna". ---- YUP!

My immense expertise?? ---- Well, at one time I had posted the fastest twenty seven (27) times at record trials on the 1/3 oval. Not all were records, since at one trial I would break and re-break my own record. ---- ALL at your expense. You set ONE (1) oval record in your entire boating life. Along with your ONE (1) straight record with the famous Crapshooter.

Marten, don't you know when to shut up?

Don Pinckert
Don:

Yes, I know when to shut up. RIGHT NOW.

You have ruined a perfectly good topic with your personal attacks and trying to convince everyone, and yourself that you are the only one who knows anything.

Marty Davis
 
Last edited by a moderator:
View attachment 6312
what would the difference of the dead rise angle of the sponson template riding surface on the left do vs the one on the right, would a steeper angle contribute to higer speeds? or if the angle is lower would the boat run faster and handle better? what would be the best compromise take a look at the templates am working with. what are your thougths anybody
The left flatter deadrise will have more contact with the water and cause more pull on that side of the boat. If you used the flat one on the left side of the boat and the more angled one on the right side of the boat it would help prevent propwalk as the left one would drag more, thus making the boat veer to the left. which compensates for propwalk wanting to make the boat turn right. You can make too much deadrise on the left sponson and boat will dig and not turn well. I prefere a 2 to 3 degree deadrise on the right sponson and a 1 to 2 degree deadrise on the left. The outsides of the sponsons determine how much slide the boat will have when cornering. Flat sides or too much straight up and down angles will make the boat trip and roll over when cornering. Too much angle will let the boat slide too much. The weight and speed of the boat has a lot to do with the angle you choose there.


John:

Interesting analysis.....

It seems that this is a perfect example to show that there are many ways to accomplish something.

First let's define Deadrise: What is deadrise? It's the angle of the boat's bottom (sponsons for an outrigger) relative to the horizontal. A flat bottom boat has a deadrise of 0°, while a deep-V might have a deadrise of 25°.

I do almost the opposite as what you have described. I keep the right sponson flat and the left with 1 degree of dihedral (for racing). The reason is that when the boat slows or goes into the turn, the sponson with the dihedral will penetrate more than the one that has a flat bottom. This penetration creates drag. I don't want more drag on the right sponson since that is the one that gets the pressure from prop torque. On most hydros in the SAW, the sponsons do not penetrate at all because of the speed and attack angle of the sponson. They are effectively only running on a TINY amount of sponson bottom anyway. Once you slow down or reduce the engine speed the prop does not press as hard on the sponson. Once you get back on the throttle, the prop forces the sponson to try to penetrate the water and you get some torque.

Another factor that must be put into the equation is the rudder location. IF the rudder is on the left, any right turn will reduce weight on the left front sponson and add weight to the right (can cause blow off). For a rudder on the right the opposite. The rudder location on an outrigger with wide sponson spacing really does not make a huge amount of difference because of the wide lever arm of the wide sponson stance.

I agree with you about the negative of having a lot of dihedral on the left sponson. It does make the sponson penetrate and you get terrible turning, darting or hooking.

One thing that is very interesting is the width of sponsons on various outriggers. On Stu's Crapshooters, he uses the narrowest sponsons that I have seen. Have you noticed how wet the boat is at launch. That is the reason. He gets a BIG advantage after the boat is up on top of the water with the narrower sponsons because he has much less drag and the smaller sponsons punch a very small hole in the air. As a comparison, the Roadrunner type boat uses a much wider run surface, gets up easily at launch and then pays a penalty with drag and hole punching. Another advantage is that you can run slightly more attack angle on the sponsons because of the narrow running surface (maybe .2 degree or so). That makes a VERY BIG speed difference because of reduced drag. I ran one of his 67 boats for a season and found out about the narrow sponson advantages. I probably would never have figured that out if I hadn't run it that season. In the past I had always run on the wide side.

For SAW, high dihedral is a huge advantage because it allows the air to spill out from under the sponson as well as reduce the contact area at speed. It also is good for turning for SAW since the dihedral will act like a turn fin at very low speeds. You can actually run WITHOUT a fin with 5 degrees of dihedral at slow turn speeds.

Much cool stuff at play with hydrodynamics on an outrigger. :)

Marty Davis
Marten, My Boy, You have just set sponson design back to the 1960's. This narrow, less drag going faster was the standard way of thinking when I started boating. ---- "Dopey Thinking".

Before I got into boating, I had spent twenty years flying airplanes. Lower wing loading flies faster, manuevers better, turns faster. I looked at the small planing surfaces and related.

I immediately started setting records that were deemed 'impossible' by the days standards. How did I do it???? ---- It was easy. I took a fiberglass boat called the Li'l Hoss, went from 1-3/4" surface to 3" surface. ---- The boat went from "clawing" to "skimming" across the water.

CRAPSHOOTER ---- In the fall of 1973, Charlie Sweet called me from Detroit. He and Tim Ries, had been laid off from Chrysler. They needed Xmas money. He asked if I minded if they took my Li'l Mixer kit and used it for a planform to build some boats? I told him it was fine with me. That is the boat and Crapshooter Company you later acquired and started producing. ---- Now, what did they do? ---- They MODIFIED it. ---- The Li'l Mixer was 32" long. Hull was 6" wide. Planing surface was 3". ---- They cut to hull width down to about 4", cut the planing surface to 2". ---- Then 'busted' their butts running new shnuerle port engines trying to break my old five year old records with side port K&B's. ---- Well, Duh !! ---- They had taken too much air from under the hull and 'firmly planted' those narrow 'high drag' sponsons on the water.

How does Stu, hear with his hippockets over his ears? ---- Skinny Minnie hulls and Skinny Minnie sponsons may be nice and water hugging stable, BUT, it 'ain't the way to go FAST.

On one hand you say flatter for speed, then you want to run 5 degree "High Dihedral" sponsons on a straightaway boat. ---- I don't know whether that is "Double Whammy" thinking or "Double Duh" thinking. ----

Now, Can you run too flat and too much planing surface on a heat racing boat? ---- You sure can.

Just read my next letter on the ROADRUNNER. Boy, do you have your hip pockets over your ears on that boat. ---- Remember, it started as a Coyote ---- MODIFIED.

to be continued ------------------- Don Pinckert
Don:

If you are going to quote me, at least be accurate.....

Did I say that Stu's approach was mine - NO. I just said it is interesting and effective. Before the Internats in Sarasota he and I were testing and getting ready for SAW Trophy Trials. The 60 boat that I was running (a heat race boat) was running 99mph. I would say that it was a dominant speed for Trophy Trials for a Heat Race boat, so your analogy about going fast with narrow sponsons might not be accurate. I presented my approach and looked at Stu's approach saying only that it was interesting. I was running one of Stu's own personal boats and enjoyed it. It was a boat that was dominant. My approach has always been to use a flat right sponson and 1 degree on the left with wide running surfaces. Did you miss this statement: "when the boat slows or goes into the turn, the sponson with the dihedral will penetrate more than the one that has a flat bottom. This penetration creates drag."

The dihedral discussion was only to point out that it was possible to use dihedral as a turn fin for SAW. 5 degrees allowed you to not run a turn fin at all. I ran VERY wide 5 degree sponsons with increasing dihedral as it moved toward the tips of the sponsons. Actually the dihedral increased to 15 degrees at the tip. The increasing dihedral was only to allow the air to vent out the sides and not stay packed under the sponsons.

Boat design has evolved since the 1960's and some of the things that were done back then have been proven to be NOT the most efficient approach.

Not sure I understand your statement

"Just read my next letter on the ROADRUNNER. Boy, do you have your hip pockets over your ears on that boat. ---- Remember, it started as a Coyote ---- MODIFIED."

You surely can't be talking to me. I did not design the Roadrunner, but I did have something to do with refining it and making it turn. I only ran Roadrunners for a couple years, mostly have run my own design.

Please provide some of your immense expertise, but please also be specific as John and I have done. We are trying to provide details to others so that they will seek out the "Why's" of model boating. The thread started by stating that both of us have used totally different approaches to timed oval and heat racing - results being similar. We pointed out that there were several ways of reaching a goal.

Please provide some specifics so that we can have a discussion..... I have no problem saying that I will try a new approach if I see merit in it, and I am positive that John feels the same way.

Marty Davis
Marten, Jennifer, was right. She said: "Don't forget, you are talking to a Midwestern Prima Donna". ---- YUP!

My immense expertise?? ---- Well, at one time I had posted the fastest twenty seven (27) times at record trials on the 1/3 oval. Not all were records, since at one trial I would break and re-break my own record. ---- ALL at your expense. You set ONE (1) oval record in your entire boating life. Along with your ONE (1) straight record with the famous Crapshooter.

Marten, don't you know when to shut up?

Don Pinckert
Don:

Yes, I know when to shut up. RIGHT NOW.

You have ruined a perfectly good topic with your personal attacks and trying to convince everyone, and yourself that you are the only one who knows anything. Time has passed you by....

Marty Davis

Marty,

I am pretty new to this sport and look to all of you who have posted in this thread as extremely knowledgeable and look up to you all for answers to th emany questions I have that have come with the pursuit of designing my own rigger. I have heard many things about Don P and his boats but again I am not able to develop and opinon as I have never run one. I do know however that everyone reaches a goal a different way, So please lets not let one persons arrogance ruin it for the whole bunch. I have found great enjoyment from reading and learning from this thread.

Zach Vought
 
Well I really enjoyed reading and learning from this thread for a while. Too bad it turned into a pissing match. Any chance it could evolve back into a "This is the way I design a rigger and this is why" Thread? ;)
 
Well I really enjoyed reading and learning from this thread for a while. Too bad it turned into a pissing match. Any chance it could evolve back into a "This is the way I design a rigger and this is why" Thread? ;)

It would be nice if we would get that to happen.

Zach
 
Thanks Don- in the future just stay the hell out of the conversation if you cant continue in a peaceful informative discussion as the previous eight pages of this thread were. :angry: SOME of us were really enjoying it- now back the the regular scheduled programming ;)
 
I always try to understand the WHY of things....(Downfall of being a Mechanical Engineer, which also explains my poor spelling)
There is always a cause and an effect relationship....BUT in the real world it is often difficult to isolate single parameters from the system.

Sure I changed this and that happened but usually other factors are changed during the process and at the moment we might not see any relationship between the variable we changed and the changes in the system that we assumed were constant.

I learned by racing cars and flying C/L stunt planes that as we make changes we see the results and think we understand....later we realize that there were also "other" factors involved that we either overlooked or didn't fully realize at the time and have to revise our options (which to me is why this stuff is interesting in the first place).

I don't personally know anyone who participated in this thread and don't know if there is any "history" amongst its contributors but I would like to say,

"I would just like to keep this thread moving forward as I for one learned more from this thread than you can image and I don't think we're done yet"

Keep it real,

Tom W
You are so right. I can't tell you how many times I have had to say I was wrong. That test was skewed by something else I was not aware of at the time. It is difficult at best to experiment with model boats and only change one thing at a time without changing something else that effects the test. Like for example: changing strut angle without changing strut depth. Both lift the transom. Here is a good example: Years ago we used to twist the strut to the left on a mono to compensate for the boat walking to the inside of the course. We were changing the direction of the prop thrust to accomplish this. What we didn't know is that twisting the strut to the left put the prop to left of the centerline of the hull causing torque roll to make the boat chine walk very badly. Over the years we learned that sticking the strut out the transom a bit to the right of centerline actually stopped chine walk all together. How did we find out............A fellow boater came to me saying his boat was chine walking very badly but it had never done it before. I said.......what did you change? He said nothing. Later that day he came back again with the same question and answer. I said..you did something, what did you do. He said the only thing he did was take off the strut bracket to change a stuffing tube and put it right back. He had remounted the strut with the strut left of centerline of the boat. I told him to loosen the screws, move the strut to the right of center and tighten the screws. The problem of chine walk went totally away. NEW WAY TO COMPENSATE FOR TORQUE ROLL>
 
Allright everybody take a deep breath an relax, lets not get off on the wrong sponson, I mean foot. Principles NOT personalities. Tom's got enough to do without having to step in an shut this down. Lets get back on track. Wheres the :wub: :wub: :wub: B) B) Ray
 
Please, please, please, please, please, please, please, please, please, please, please, please, please, please, please, please, please, STOP using the "qoute" function! :angry: :angry: :angry: :angry: :angry: :angry: :angry:
 
Marty, on the 1/8 scale skid fin. I crewed on the full size boats for a few years and they are not just flat. There is a specific cut in the fins that helps hold them down. We tried the bend in the bottom of the fin back in 1986 ask Ron Synder how he liked it in Evansville? (sore subject for me.) Plus it was not until this year that a rule was made of how a skid fin could be cut or bent. I have tried the bent fin on my boat it lifted the right side and made it act lose and out of control. But that was my boat with one test session. I have been running the same design skid fin for the last few years and I like that set up. I tried another design at Celina this year and I did not like it at all. I have gone back to old faithful, but once again this is my boat and it is what I like. I am not saying that everyone has to run what I do. But run what you like or go play with a new design. Heck there could be a new design that no one has tried yet that is the cat's meow. So I say to everyone quit bickering and go out and try something new or old and have FUN! Hope to see you all at a race some day and we can all have some fun. Life is to short to argue over small stuff.

Don McKay
 
Two rules................

1. Don't sweat the small stuff.

2. It's all small stuff.

We started with deadrise and got off course with turn fins and rear sponsons. I even talked monos! oh my ! we can learn from it all.
 

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