Rigger Set-up

[Joe_Knesek]

I'm in the process of building a new set-up table and would like your feedback.

Most set-up sheets talk about sponson attack angle but I wonder if it's not more important to measure slope instead of just angle.

The reason I ask is because of the 4 differant types of sponsons I measured, none have the same slope. This means that if I set the front sponson height @ .500 6 inches from the trailing edge on each sponson, @ 3 inches, I may see measurements of .300, .250 or .200 depending on the slope of the sponson. So the even though the 6 inch measurement is the same, the sponson with the .200 @ 3 inches will run wet compared to the one with .300.

Does this logical and does it matter?

 

[Norm Doerr]

I'm in the process of building a new set-up table and would like your feedback.
Most set-up sheets talk about sponson attack angle but I wonder if it's not more important to measure slope instead of just angle.

The reason I ask is because of the 4 differant types of sponsons I measured, none have the same slope. This means that if I set the front sponson height @ .500 6 inches from the trailing edge on each sponson, @ 3 inches, I may see measurements of .300, .250 or .200 depending on the slope of the sponson. So the even though the 6 inch measurement is the same, the sponson with the .200 @ 3 inches will run wet compared to the one with .300.

Does this logical and does it matter?

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Set it up at some neutral starting point making sure both sides are the same. Then after you dial it in you will have your numbers to use on the table if you bend something. If the riding surface has much more than three degree it will go fast but not be as stable, (depending on the boat). Somewhere in the 3 degree range seems to work for heat racing with boats like RRunners and ect.

 

[dave roach]

Joe

Go to marty web site he has a neat wat to set the front sponsons.

 

[Norm Doerr]

Joe Go to marty web site he has a neat wat to set the front sponsons.

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Yup. That is the ticket. I don't even use the table until the thing is running the way I want it then we go to the table to see what we have. If it is a Roadrunner do what he says on the website and the thing will run great in heat race water.

 

[Joe_Knesek]

I'm in the process of building a new set-up table and would like your feedback.
Most set-up sheets talk about sponson attack angle but I wonder if it's not more important to measure slope instead of just angle.

The reason I ask is because of the 4 differant types of sponsons I measured, none have the same slope. This means that if I set the front sponson height @ .500 6 inches from the trailing edge on each sponson, @ 3 inches, I may see measurements of .300, .250 or .200 depending on the slope of the sponson. So the even though the 6 inch measurement is the same, the sponson with the .200 @ 3 inches will run wet compared to the one with .300.

Does this logical and does it matter?

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Set it up at some neutral starting point making sure both sides are the same. Then after you dial it in you will have your numbers to use on the table if you bend something. If the riding surface has much more than three degree it will go fast but not be as stable, (depending on the boat). Somewhere in the 3 degree range seems to work for heat racing with boats like RRunners and ect.

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Norm & Dave, thanks for the feedback but I'm I'm aware of the proper set-up process and angles & I've read Marty's work. What I'm after is the impact of the sponson's slope.

 

[dave roach]

Joe

You talking about the slope on top of the sponsons.

 

[Joe_Knesek]

JoeYou talking about the slope on top of the sponsons.

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The bottom. Some sponsons have a lenier slope and some have a progressive slope. Using the example above, the lenier slope would have a midpoint of .250 while the progressive slope could be .200 @ the midpoint. The sponson with .200 should run wet compared to the one @ .250 even though the 6 inch mark is the same. :huh:

 

[shoboat]

Joe,

Maybe KP will post some of his wisdom on the subject?

I still like the marble set up table and my digital angle finder.

On my new boat we just go to 2.8 degrees and go test to fine tune

the strut angle. She will be ready soon. I would think you are creating

a lot of work for yourself,I hope you get the results you are looking for.

Good Luck Testing,

Mark Sholund

 

[Nigtmare]

Joe you don't measure the slope!!!you measure the engle of the sponsor=to the tub. the last 2"3" of sponsor is flat anyways. so just think that the tub is flat to the water,and the sponsors 3 degrees up from the tub.

Nick

 

[gil sonsino]

Hi Joe

It really doesn't matter these measurements but what Nick and Mark properly pointed out.The last 2/3 of your sponsons should be flat and from that you will angle them with the tub.

I like to build my riggers using an alumiun jig so you can see it in my gallery instead of a building table.

By the way it allows me to build any size of boat easy and accurately not to say that helps a lot for periodic chek ups on the set ups or repairs.Do not forget to get a digital level too!

Gill

 

[Ron Jefferson]

Joe: I think you're talking about what Marty refers to as the "belly" of the sponson. There has been a bunch of talk on his site in the past. A long time ago I posted asking several questions on building measurements for .40 boats. Best I could figure was the belly, or bottom slope was more for launch than all out speed. Maybe Marty or Andy could help out here. Too technical for me.

Ron

 

[gil sonsino]

That's right Ron.If you take a look to a SGX sponson botton you will see exactly that...aprox 2/3 of this area is absolutely flat and the "belly or slope"( in front)just helps for the very first start during the launch.

I think the more important here is the final attack angle of the sponson on water to keep the boat not too much wet . Something around 3 degree has worked great for heat riggers but can vary from the different designs. On my own designs I use the same concept even for saw races and my boats have run great.

Marty's thread shows a high level discussion and can clear many doubts on this subject.

Gill

 

[Joe_Knesek]

That's right Ron.If you take a look to a SGX sponson botton you will see exactly that...aprox 2/3 of this area is absolutely  flat and the  "belly or slope"( in front)just helps for the very first start during the launch.I think the more important  here is the final attack angle of the sponson on water to keep the boat not too much wet  . Something around 3 degree has worked great for  heat riggers but can vary from the  different designs. On my own designs I use the same concept  even for saw races  and my boats have run great.

Marty's thread shows a high level  discussion and  can clear many doubts  on this subject.

Gill

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Gill, I think you hit it. as long as you measure the flat area only, you are ok. If you use the 6 inch measuring mothod Marty writes about, you will get a different result based on the amount of slope within that 6 inches.

All this discussion is actually in preperation for building a new set up table. I wanted the opinions before I start cutting & drilling the table.

 

[Norm Doerr]

That's right Ron.If you take a look to a SGX sponson botton you will see exactly that...aprox 2/3 of this area is absolutely  flat and the  "belly or slope"( in front)just helps for the very first start during the launch.I think the more important  here is the final attack angle of the sponson on water to keep the boat not too much wet  . Something around 3 degree has worked great for  heat riggers but can vary from the  different designs. On my own designs I use the same concept  even for saw races  and my boats have run great.

Marty's thread shows a high level  discussion and  can clear many doubts  on this subject.

Gill

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Gill, I think you hit it. as long as you measure the flat area only, you are ok. If you use the 6 inch measuring mothod Marty writes about, you will get a different result based on the amount of slope within that 6 inches.

All this discussion is actually in preperation for building a new set up table. I wanted the opinions before I start cutting & drilling the table.

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Joe;

Go to a kitchen/cabinet shop and get a composite counter top sample I have Marty's old set up table and it is the best set up table I have ever had. It will not warp and it is a true "flat" surface. Just clean it with brake clean once in a while.

Norm

 

[Ron Jefferson]

A buddy of mine in the glass business cut me a hunk of 3/8" glass that was busted in a store front accident. Approx 2.5 x 4'. It doesn't have slots or anything cut in it but it sure is flat. I either remove the rudder and turnfin or hang the boat close to the edges.

Joe: I understand about the slope etc. I believe Marty's measurements are only guidelines, or a starting point for setting up your hull. The digital level plays a much bigger part in my opinion. I know Marty gets into setting his angles different from side to side to improve turning and handling etc. Working on set-up is definately going in the right direction. Approx 2.8 and 1.8 is where my current boat is set-up.

Ron

 

[Marty Davis]

Joe:  I think you're talking about what Marty refers to as the "belly" of the sponson.  There has been a bunch of talk on his site in the past.  A long time ago I posted asking several questions on building measurements for .40 boats.  Best I could figure was the belly, or bottom slope was more for launch than all out speed.  Maybe Marty or Andy could help out here.  Too technical for me.
Ron

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Ron:

The belly on sponsons is for a couple reasons. It makes the sponson bottom have a higher attack angle forward where it helps at launch (also makes the sponson wet less at launch). Also it will give more bouyancy in the turns. The sponson tends to wet (penetrate the surface) less with some belly. For SAW, I liked to have almost zero belly.

One note on the answer by Norm Doerr about the 3 degree attack angle. On a boat with a forward cg the 3 degrees is a good starting point, BUT on a boat with a rearward cg (Andy's) 3 degrees is too much. Bottom line, it is different for each different design and must be trial and error to get it right.

Marty Davis

 

[gil sonsino]

The less belly design is better for saw because it has less airlift too!

Thanks

Gill

 

[Joe_Knesek]

That's right Ron.If you take a look to a SGX sponson botton you will see exactly that...aprox 2/3 of this area is absolutely  flat and the  "belly or slope"( in front)just helps for the very first start during the launch.I think the more important  here is the final attack angle of the sponson on water to keep the boat not too much wet  . Something around 3 degree has worked great for  heat riggers but can vary from the  different designs. On my own designs I use the same concept  even for saw races  and my boats have run great.

Marty's thread shows a high level  discussion and  can clear many doubts  on this subject.

Gill

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Gill, I think you hit it. as long as you measure the flat area only, you are ok. If you use the 6 inch measuring mothod Marty writes about, you will get a different result based on the amount of slope within that 6 inches.

All this discussion is actually in preperation for building a new set up table. I wanted the opinions before I start cutting & drilling the table.

89058[/snapback]

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Joe;

Go to a kitchen/cabinet shop and get a composite counter top sample I have Marty's old set up table and it is the best set up table I have ever had. It will not warp and it is a true "flat" surface. Just clean it with brake clean once in a while.

Norm

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So far, I have had no luck with the local shops. I can get Corian from an art shop in NY but it's just as expensive as phonalic.

 

[shoboat]

Joe,

How big of a piece are you looking for?

Thanks,

Mark Sholund

 

[Joe_Knesek]

Joe,
How big of a piece are you looking for?

Thanks,

Mark Sholund

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17"x24"x1/4"