What happen to the rounded off pickle fork rule

[ryan_4z]

Steve,

I am setting up a vacuum table and planning on experimenting with different layups. I am open to suggestions as to what the sides should consist of and I would be willing to make some samples of different composite sides to be tested.

I think that, if you are going to do some testing with this, that you must take cockpit length into consideration. A 5' long cockpit side will flex and break much differently than, say, a 2' sample piece.

[ryan_4z]

I agree with Ed (wow, I can say that). While on the PRO commission several safety proposals were made that appeared to have merit (including some in this thread), but there was no supporting data or research. My concern as a commisionser was to inadvertently place drivers in a more compromised position than when we started. And the conventional wisdom around the table was not close to being unanimous as to the direction to take, so no change was made.

This is another very valid point. We don't want a rule that gives drivers a false sense of security.

[G Stillwill]

I already reinforce the sides with Kevlar and have been on the last few boats that I built do I think it will stop a 350 to 500 pound mass traving at between 60 and 90 mile an hour not on your life. I dont really expect anything will short of a diamond plate wall at least 4 foot high. The force has to go somewhere if not through the boat it will go over it and then you deal with the fin,lower unit and prop to take the driver out with much more leathle results. The law inforcement and gov has been looking into a new system that is being experimented with now where the kevlar material is supended in a liquid state and works much better then the dry system which they use now. There is also a new material which I was going to use in the boat that Im building now but didnt as there was no test data on it. The stuff ia call Zylon and supposed to have twice the strenght of Levlar 49 with the same weight. I just read in the proppler that the insurance company is keeping the same rates as our accident rate has came down and not increased. Maybe some of the other rules need to be looked at in the clases with the most accidents to see if the speeds need to be slower and not so much on the edge, boy that opens up a can of worms

[G Stillwill]

Some test data

http://www.tuskegee.edu/Global/story.asp?S=5778977

http://www.grc.nasa.gov/WWW/RT2001/5...30pereira.html

http://www.sri.com/psd/fracture/reports.html

http://www.alcoa.com/bcs/aap_eastman/kevlar/en/news.asp

http://www.military.com/NewsContent/...042104.00.html

http://www4.army.mil/ocpa/read.php?story_id_key=5872

http://www.udel.edu/PR/Messenger/04/01/liquid.html

[jsilvestri]

Those of you who are thinking of doing some testing of panels should contact Marc Johnson as he has been through this with his capsules and is very knowledgable on this subject. You might save yourself some time if you call Marc and talk to him first.

[Dave M]

Bingo Joe

Those of you who are thinking of doing some testing of panels should contact Marc Johnson as he has been through this with his capsules and is very knowledgable on this subject. You might save yourself some time if you call Marc and talk to him first.

If memory serves, he has already submitted to APBA approval his panels. They were passed for OPC.

Also, I can vouch that Marc does a lot of his own testing. If you name a layup, chances are, Marc has tested it.

Here is what I had on my last Pro boat. The foam core you use makes a large difference, much more than the fabric in terms of stiffness. The fabric you use determines how light the panel will be.

Use 10oz glass, then 5 or 6 oz Kevlar. then foam core, repeat. Bag this on the table and use PLENTY of epoxy. To often you try to save weight by going light on the epoxy. This creates a weak panel.

Do I feel this would stop an intrusion at 90 + MPH. Nope. It would deflect the intruding boat either up, to the rear or to the front. Which way depends on the angle of attack the intruding boat strikes.

Here is what I think might stop a boat going 90 plus and still maintain some semblence of a race boat weight.

use three three layers of Kevlar laid up at 45 degrees of each other. Meaning they oppose each other. In between each layer use some 10oz S Glass. Not E Glass. There is a huge difference. Now then, if available one could substitute some 6 oz twill weave carbon for a layer or two of the glass. But you need the glass to get the stiffness. Kevlar sucks for stiffness and so does Carbon Fiber. It is stiff, but not good enough in my opinion.
Next use your foam core. Then repeat on the next side. For an average cockpit length of a D class boat I am betting each side will come in around 20 pounds. One thing that needs to be used is West System. It is expensive, but from all the data I have gathered, it has the best physical properties of all the epoxy out there I have seen. Do NOT use the fast hardner. Use the slow. The fast hardner takes away the physical properties. This data is available from the West System website.

So there is my two cents. Steve, you have my permission to lay up the above recipie and test it. Please video your tests so we can all see exactly how you are testing it and offer some insights to your methods if needed.

I am sure you know how many different style of fabrics are out there and how each one has different uses. About the only standard is Kevlar. Easy to find in 5.9oz regular weave. To find anything else is not easy for Kevlar, and it gets pretty expensive.

The material which George speaks of works okay. I have not tested it but laid up a piece of it once and it seems to be similar. But I have not used it in construction yet.

The only drawback is people building there own boats, you can't regulate what materials they use. And that is a big problem.

[csh2z]

The three major concerns of mine (and Dave touched on it in his last post) are Inspection, enforcement and penalty for non-conformance. I don't know how these items are dealt with in the other categories or UIM. I hesitate to endorse any rule without those questions answered.

[modhydro]

Panel testing

Dave,

I used to make safety cells for the inboard division and went through the whole approval process as well.

What I would like to see happen is two things:

We need to arrive at one approved sponson tip design. I see this as the biggest factor simply by virtue of increasing the area that would penetrate and thereby dramatically lowering the PSI that any cockpit side needs to withstand.

Secondly is to arrive at an approved cockpit side construction. While we need to design towards safety, we also need to design towards practiacallity. How many people do you know that are capable of vacuum bagging a composite panel? We need to keep in touch with the fact that many people build their boats in home shops without special tools and equipment. We need to work within some simple parameters that should be able to still allow this without sacrificing safety.

What we end up with may not be compliant with the rules for UIM. The way I see it, that would be just fine. If you want to run in any sanctioning body, you need to be sure that you are within their rules. By setting guidelines for construction we are in no way limiting a person to the spec. You can always go above and beyond.

Just some more thoughts.

Steve

[raceboat61-S]

Steve, et al,
For those of us that want to retrofit our hydro's (or even most runabouts) but lack the expertise and equipment to vacuum bag components, I suggest that we simply saw off the ends of sponsons about 6-8" inches back from the points. Replace with a flat plate of 4-6mm plywood epoxied to the blunt nose and form a frangible nose cone of styrofoam that is glued to the plywood. Foam blocks made from styrofoam or from spray can applied expanding-foam insulation can be filed and sanded to the previous shape/size and if the builder wants to paint the styrofoam it would be invisible from the beach. The hard part of the sponson tip would be at least a big as your hand and would likely reduce the penetration possibilities significantly without sacrificing structural integrity or strength.
The next thing we need to address is the leading edge of the airfoil that is between the sponson tips. At the speeds we race, we don't need a knife-edge on this airfoil. A fat wing with a leading edge with about the same radius of a tennis ball would be better. Drawback is that this would require an entirely new boat. The center of lift of the airfoil would be altered tremendously. Still, if you get cracked in the head, you are dead. Mike Marshall, Raceboat61-S

[ryan_4z]

The next thing we need to address is the leading edge of the airfoil that is between the sponson tips. At the speeds we race, we don't need a knife-edge on this airfoil. A fat wing with a leading edge with about the same radius of a tennis ball would be better. Drawback is that this would require an entirely new boat. The center of lift of the airfoil would be altered tremendously. Still, if you get cracked in the head, you are dead. Mike Marshall, Raceboat61-S

I don't see this as being an issue at all. You aren't going to get punctured, or cut by this, no matter how thin it is. I don't think that making this more blunt would make a difference at all.

[sam]

simply saw off the ends of sponsons ... form a frangible nose cone of styrofoam Foam blocks made from styrofoam or from spray can applied expanding-foam insulation can be filed and sanded to the previous shape/size Mike Marshall, Raceboat61-S

Someone else suggested breakaway sections from balsa ... I'm leaning that way.

We are going to have to get out of the habit of grabbing and lifting hydros by the sponson tips ... when I blunt mine and make frangible tips I think I'll paint the tips orange to remind everyone they are not structure

[Blackhawkguy]

My two cents

Wow, quite a diference of opinion on several topics. First I like what Ed had to say around page 2 about driver equipment I believe it was. It seems a little useless to me to wear kevlar pants and sleeves that are so worn out I doubt they would even stop a mosquito from penetrating them, yet when you walk through the pits that is what you see. Or if your helmet was hit or dropped at any time did you send it back to the manufacturer as they request? Rounded tips or not? Hard to argue againts them but doubt they will stop cockpit penetrations completely, and as posted a few pages ago will they then open a whole new problem of deflecting the boat into the drivers head, seems once you fix one problem the next weekest point shows up. A perfect example was the capsules in the tunnel boats. Because the drivers where strapped in and surrounded by kevlar they thought themselves invinceble, so they quit driving with caution, if you drove a tunnel boat the way they did before the capsules you would find your self dead quite quickly. the next issues were capsul penetration problems that never excisted before, then the crushable tips where implemented.
The next problem seems to be seats put into capsules, why I do not know, but there are two drivers paralized because of this. My point being you can only make racing so safe, accidents happen and the more that happen the more you find the week spots. I always thought the best way to stay safe was not fall out of the boat, race hard but know your limitations, things will happen but carelessnes is not racing, it's just carelessnes.

Kerry

[sam]

It seems a little useless to me to wear kevlar pants and sleeves that are so worn out I doubt they would even stop a mosquito from penetrating them, yet when you walk through the pits that is what you see. Or if your helmet was hit or dropped at any time did you send it back to the manufacturer as they request?

Or Kevlar held on with tape ... if your pants need tape, you need new pants. I have no idea why referees and risk managers are allowing this

[ryan_4z]

Or Kevlar held on with tape ... if your pants need tape, you need new pants. I have no idea why referees and risk managers are allowing this

So just because you may have a broken zipper, your kevlars are no good?

[HRTV]

So just because you may have a broken zipper, your kevlars are no good?

Thats correct Ryan throw them away or have them fixed by a certified vendor me personally I would just trash them.