Rigger Sponson Design Q: Trailing Edge

[Gerwin Brommer]

I can imagine people calling a sponson with rails "another lifting BODY" ???
By nr.1 drawing , I mean : the one on the left, with the hull attached :-)

[Meniscus]

I often see all kinds of designs when it comes to SAWS whether it be fins, ride pads, neutral air over the sponson wash if any, extra edges, etc. I don't think anyone could pull a rule on something that was implemented such as this. See some examples below:

DSC00058.JPG ChrisHarris_Rigger_Front.jpg DSC00046.JPG

5170-Rocket.jpg 303-Nurnberg.jpg

I think anyone could claim anything, but the point is neutral with the least amount of drag on the water first, but more importantly, in the air.

[Ub Hauled]

I think anyone could claim anything, but the point is neutral with the least amount of drag on the water first, but more importantly, in the air.

not sure if I understand Ben, I think the most important is the drag that water creates, not the air... granted that both need to be addressed...
Joerg was telling me (or was it Arnie?) that the JAG's boats were effectively riding on the prop only... there was a very thin cushion of air on the sponsons and the prop was the only thing on the water... now, this would work ONLY if the water was a mirror otherwise there would be a lot of drag added every time the sponsons touch the water.
Also I am only mention the Germans because it worked well for them.
I am not sure what type of sponsons Brian is using these days, but I am sure it uses the same principal as the GR do, it may look different then the "torpedo sponsons" but I think we can safely say it's working for him.

[Chris Harris]

Boy that boat in the middle on the top row is a real beauty! LOL

First the legality issue. If it's a rigger your talking about doing this on then there is no problem.

What John and some of the others have said as well as the quote you posted are on the money. I think I understand what you are getting at here but compairing heat racing and SAW sponsons is apples to oranges in my book.

In heat racing you need the sposons to have some contact with the water to keep the boat stable. Afterall straightline speed is not the main goal with an oval boat but overall laptime is, which comes from how well the boat gets around the buoys as as well as straightline speed.
What Jan said about the Jags SAW boats is what is needed in SAW to go REAL FAST. My sponsons on my SAW rigger are totally off the water when they are at speed but this is accomplished (at least on my boats) by more than just the sponson design. The lift of the sponsons work in conjunction with the lift characteristics of the tub to get the desired effect. If you were to put my SAW sponsons on a more traditional type tub the thing would blow off like crazy.

The only way to know for sure if what you proposing will work is to build it a try it which is half the fun.

Chris

[Chris Harris]

Boy that boat in the middle on the top row is a real beauty! LOL

First the legality issue. If it's a rigger your talking about doing this on then there is no problem.

What John and some of the others have said as well as the quote you posted are on the money. I think I understand what you are getting at here but compairing heat racing and SAW sponsons is apples to oranges in my book.

In heat racing you need the sposons to have some contact with the water to keep the boat stable. Afterall straightline speed is not the main goal with an oval boat but overall laptime is, which comes from how well the boat gets around the buoys as as well as straightline speed.
What Jan said about the Jags SAW boats is what is needed in SAW to go REAL FAST. My sponsons on my SAW rigger are totally off the water when they are at speed but this is accomplished (at least on my boats) by more than just the sponson design. The lift of the sponsons work in conjunction with the lift characteristics of the tub to get the desired effect. If you were to put my SAW sponsons on a more traditional type tub the thing would blow off like crazy.

The only way to know for sure if what you proposing will work is to build it a try it which is half the fun.

Chris

[Meniscus]

Boy that boat in the middle on the top row is a real beauty! LOL...

Now that's funny! I guess that rigger looks OK. The real question is whether or not it works! That is a very nice rigger Chris.

I understand the input provided and all makes sense. Chris, have you experimented with anything like this?

Let me know when you have time available in your wind tunnel for me.