2008 EZ-Slalom

The EZ-Slalom HeavyDuty Slalom Course

Defining "HeavyDuty"

When you first see the words "heavy duty" the picture that most likely comes to mind is of something massive, strong, and obviously built to last. That's certainly what we think of anyway. Before we could call our permanent slalom course systems "heavy duty" we had to assure ourselves that they would fit the bill. So we researched and tested the materials we use for our EZ-Slalom HeavyDuty courses until we were absolutely certain that we could indeed consider them to be "heavy duty".

At the same time we also took into consideration the trade-off between structural rigidity, materials strength and durability, and price. Is it possible to build a better slalom course than an EZ-Slalom HeavyDuty? In a word, perhaps. For example we've seen information on the internet from folks who have built permanent slalom course buoy arms using 2" square aluminum tubing, steel angle iron, and even 6" aluminum irrigation pipe! We've heard of folks using 3/8" steel cable for slalom course mainlines. Is that "better"? It may posibly be "stronger". Better though?

To build courses such as these the investment of time and funds is significantly higher than what you'll invest in a EZ-Slalom HeavyDuty course (which by the way is warranted against failure of materials or workmanship for ten full years!). If you want such a course we can definitely build it for you if you'd like, or we can customize a mainline or course kit to work with your 2" square aluminum tubing, 6" aluminum irrrigation pipe, or whatever materials you choose if you wish to do it that way. Realize though that the final cost to build such a course will be much higher than the price of a stock 10-year-warranty EZ-Slalom HeavyDuty course while the tradeoff between structural strength and price will likely be well past the point-of-diminishing-returns, at least in our studied opinion.

So the real question then is this - Do any of our competitors build a better permanent slalom course than an EZ-Slalom HeavyDuty? No, they don't. Here's why.

First off, the stainless steel cable we use to build our mainline is the same exact cable our competitors also use. Same size, same strength, same manufacturer, same cable. How do we know this? We purchase our cable from the same supplier our competitors purchase from, who happens to be the largest supplier of such stainless cable in the United States. This mainline cable is 3/32" in diameter (coated to 3/16"diameter using a clear, flexible PVC coating) or about the size of #12 electrical wire. You're wondering how such small cable can possibly be strong enough to hold up under high tension for extended periods of time (several years) while immersed in water? So were we.

The manufacturers break strength rating for this cable is 920 pounds of tension. Pretty tough stuff, especially considering it's diminutive size. Not being satisfied with that we went the extra step of having this cable break strength tested to insure that it is as tough as advertised as well as to satisfy ourselves of its strength. To our surprise, despite the manufacturers rating the cable tested out to be even stronger than advertised! Of over a dozen samples tested the lowest failure rating for any of our samples was 1050 pounds of tension, easily well beyond the amount of tension required to keep your course dead-on straight. Certainly then, this cable while not being massive in size is definitely strong enough to meet anyone's definition of "heavy duty".

OK, so this cable tests out to over 1000 lbs of break strength. What does that really mean to the user? To get your course to go and to remain straight you need to tension the mainline enough that nothing can cause it to bend or bow. In our testing we've discovered that a tension of 150 - 200 lbs will get and keep your mainline fiddle string tight and completely straight in almost all conditions (a high crossing breeze being the only possible exception - in which case it's likely too rough to do any skiing anyway). So yes, we believe that the term "heavy duty" is apt here.

So What Makes Our Mainline Better?

So if we use the exact same stainless steel cable to build our mainlines as everyone else uses, what makes the EZ-Slalom cable mainline different? Two words. Superior engineering.

EZ-Slalom Diamond Diagram

The most common way to attach two pieces of steel cable together is by crimping them together. No rocket science there. One of the main issues in designing a slalom course mainline is that where the buoy arm attaches to the mainline a connecting system of some sort must be created to stabilize the buoy arm perpendicular (that is, at a 90 degree angle) to the centerline of the mainline. This structure is known as the diamond due to the shape that is created when the buoy arm is attached at this point. The diagram above illustrates what the diamond looks like, how it's constructed, and how the buoy arm attaches to it. Basically you have one cable at the centerline of the course running from diamond to diamond positioning the buoy arms at their correct locations throughout the course. Where the diamond is located (where the buoy arm is attached to the mainline) you have that one cable attaching to two separate cables with each of the two cables attached to the buoy arm at either side of the boat lane section of the buoy arm. See the diagram above for more detail.

How Do Others Do It?

Others attach the mainline's centerline cable to the cable sections that create the diamond using one crimp at each of the two end points of the diamond. They're connecting three cables together at this point, the one centerline cable intersecting with the two halves of the diamond. This one crimp is required to handle two different types of tension load, axial load and radial load. Axial load is the tension applied to the course's mainline to keep the course straight. Radial load is the sideways load placed on the crimp by the two halves of the diamond being spread apart by the buoy arm attached to it. See the diagram above for details.

Asking one crimp to take these two different types of load at the same time, and placing that entire load on only one crimp is asking a lot of that one crimp. Especially if you're using an aluminum crimp at this point, as our competition does. Aluminum is a relatively soft metal which when attached onto a dissimilar metal (the stainless steel) and then immersed in water (which aluminum crimps are not specifically designed for) subjects the crimp to galvanic corrosion. This potential for corrosion in combination with all of that load placed on only one soft crimp can cause the eventual weakening and/or failure of that crimp.

How Does EZ-Slalom Do It?

With the EZ-Slalom HeavyDuty mainline we divide that load between two crimps rather than just one. First, we build each of our diamonds separately by using two sections of cable with each cable staggered so that it leaves a tail at each end point of the diamond (see the diagram above). So at the diamond's end points there are only two pieces of cable being attached together, not three. Building the diamond in this manner places the entire radial load on only one crimp at each end point of the diamond. We then attach the remaining tail at each end of the diamond to another cable which runs from diamond to diamond. This second crimp takes the majority of the axial load. Thus we divide the tension load placed onto the cable between two crimps rather than putting it all on just one, lessening the load on each crimp and reducing the likelihood of failure at any crimped point.

The crimps that we use for our EZ-Slalom HD mainline are themselves different as well. Where others use aluminum crimps not specifically designed for marine applications, we use a crimp made from hardened copper and zinc that is manufactured specifically for use in a marine environment. Again, to ensure their strength was up to the necessary standards we've had these crimps laboratory tested with our cable to measure and ensure their resistance to failure under tension. In all of the samples tested these crimps held at least as much tension as the cable did before failure. Plus they're much more resistant to corrosion and therefore much less likely to fail. Better materials combined with better structural engineering, resulting in longer service life of the mainline and reduced likelihood of failure.

HeavyDuty Buoy Lines

We also went beyond the norm to construct our permanent course buoy lines. Rather than going without any shock absorption whatsoever (which transfers more shock and vibration to the mainline and buoy arms, accellerating wear and reducing service life) or just using ordinary shock cord (which has limited service life) we utilize durable large diameter surgical-grade rubber tubing for shock absorption. These buoy lines will last seasons under normal conditions without failures caused by materials breakdown. We don't just tell you they'll last, we back it up with our warranty. Our HeavyDuty buoy lines are standard issue for all of our HeavyDuty permanent courses and HD course kits and can also be added to our portable courses as an option.

That's how we build all of our products at EZ-Slalom. We find the best available materials, combine them into the best engineering designs available, and price our products very competitively.

Best Built! Best Engineered! Best Value! That's why EZ-SLALOM is The Standard in Portable Water Sports Courses!

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Thank You for taking the time to review our information. If you have a question about something not covered here and would like to request a brochure, additional information, or would like to discuss any issue with us person-to-person please contact us by e-mail to info@ez-slalom.com or call us toll free at 800-216-4461. We enjoy answering your questions and we'd love to hear from you!

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