CsSkis

@Wish I don't know how to comment on Connelly's information. The biggest question that I would ask is what kind of "tunnel" test they used and how the testing was conducted. It would be nice if they published a technical report on how they did it. Up to this point, I am not aware of any formal, lab-based, testing that could replicate how we interact with a waterski and determine what does and doesn't work in a slalom course. (I wish there was!!!) And, when Connelly talks about validating it on the water... testing a waterski is, to all intents and purposes, based on highly subjective feedback. Just ask Horton!

 

Does it sound like I think that I know everything? I hope not, as it gets proven to me every day of the week that I don't!

 

Just for fun, I have attached a picture of the spray off a ski that was being tested a few years back. The only "data" I acquired on how it worked was all based on subjective feedback. However, it turned out that fin tuning was a stronger influence on the feedback than the design of the ski itself.

@ThePantsManCan I'm glad that you understood about requiring air to ventilate the step and that carrying the step around/over the bevel might alleviate the suction. Unfortunately, a waterski is much more complex than the planning hull of a boat. Boats are typically going in a straight line (traveling point-to-point). Running a slalom course is just one linked turn after another. If you look at any picture of a waterski as it is passing through the water (cross-course or otherwise), either one side or the other is always immersed in the water from about the front foot to the tail. So, what would be the purpose of adding steps?

 

There is something else about boats versus waterskis. When a boat is on plane, most of the water molecules are traveling longitudinally under the hull. There is some bow and hull spray, but most of the water is passing under the hull. However, and we are all proud of this one, slalom skiing is defined by the spray we generate! The spray is a graphic way of showing that a large proportion of the water molecules are travelling more laterally (typically, about 30 degrees) across the bottom of the ski. (Refer to attached picture of Rossi)

 

There is one point at which the waterski is acting similarly to the planning hull of a boat, but it is very, very, brief. It is during the edge change. (Refer to attached picture of Smith) The ski is unloaded at this point and the planing attitude reflects that fact. However, it also occurs in the "whitewash" which is already well "ventilated". So, steps wouldn't contribute to a lowering of drag at this point either.

 

Food for thought.

@ThePantsManCan Please read my previously linked article on how/why stepped hulls work before you invest much time/effort on a stepped ski. If you really want to start tinkering with your old ski, start thinking about how bevels work and how different bevel shapes change where the flow separates on the sidewall of the ski. A round bevel creates more suction and a sharp bevel reduces it.

 

@Wayne Always ask - what is the change in the surface supposed to do - is it marketing, or is there a real reason for the change? My guess is that the dimples were there for marketing purposes.

@The PantsManCan

 

Whoa...forward facing bumps! You might/should reconsider that. Those bumps, even with very little forward facing area, will markedly increase the drag of the ski.

 

I would guess that a whale's tubercles are a natural form of vortex generator - intended to help with laminar flow on the fin/flipper. For all intents and purposes, a waterski does not experience laminar flow.

 

Oh, and here is a link to an article that Adam and I have discussed in the past:

http://www.navaldesign.co.za/articles/Stepped%20Hulls-%20Feb07.pdf

On the thread talking about Glen Campbell's performance at Worlds was a side discussion regarding Cale Burdick and his (phenomenal) performance at Worlds, along with his use of a "Frankenski". I just wanted to clear something up. The skis (there are actually two Frankenskis) were built and set up by Adam Cord especially for Cale. Based on his performance, it appears that Cale has made very good use of them.

Nope, wooden Maherajah That is a doctored picture of Kris LaPoint, if I'm not mistaken

Please go to the "C's Skis - Simple glove modification to reduce/prevent sore hands" The whole reason I came up with the mod was to address the problem you describe. I can't guarantee that it will eliminate your sore hands - but, everyone who has tried the mod has been a "happy camper" so far.

@Steven Haines: I'll paraphrase something that I said on the D3 Rockerblock thread. If your ski is flexing significantly in the last 8 -10 inches, I would be very worried. In order for that section of the ski to flex, the carbon laminates would have to be extremely thin, and it would have to be the top sheet that was providing the "give" in compression. So, no, I didn't construct the fin block to preserve flex. The motivating factors were the ease of adjustment, simplicity and light weight.

@eleeski: I second everything you stated. Personally, I just did it for fun. However, regarding hollow skis, I don't discount the work/accomplishment of Adam Cord with the AM33.

This one is just for entertainment!

 

Before Adam Cord developed the AM33, he was experimenting with how to build a hollow ski. So, as a starting point, he took one of his old Elite's and pulled a mold off the bottom of the ski. After he was done, the ski was a little "worn" looking and he let me have it for experimentation purposes.

 

My approach was a little different than his. I took a Dremel moto-tool and cut through the carbon top deck of the ski. I then peeled off the carbon layer and used a coarse grinder on a hand drill to remove the foam core - with some cleaning up required with the moto-tool. (You will note I left the inserts in place. Before grinding, I made a reference template of the insert locations.) I added a layer of carbon in the tip area to strengthen this section of the ski and used J-B Weld to build a small flat area on the outside edge of the tip section of the ski (these 2 steps were required due to limitations in the way in which the tip area of the Elite is formed).

 

In discussions with Adam, it was agreed that a single layer of carbon for the replacement top deck would not be sufficient and that two layers would be required. (That's one of the advantages of a foam core. It keeps the laminates from "oil canning" and less material is required.) So, I needed to lay up a carbon top deck........

 

I had "access" to a glass topped dining room table, as well as a couple of additional sheets of glass. After mixing up resin and laminating two layers of ski-sized carbon cloth, I laid the laminate between sheets of thick acetate, placed it on the dining room table, covered it with the additional glass, and weighted the whole thing down with canned goods from the pantry to squeeze out excess resin. (Yes, you can go ahead and laugh. At least I have a very understanding wife!)

 

I let the laminates cure for a day. (Without heat, the resin won't completely cure in a day. It will still be slightly flexible.)

 

The next day I peeled the laminated sheets off the acetate. (The acetate leaves a very nice finish.) and used J-B Weld to bond the top deck onto the "de-cored" ski. In order to get enough pressure, without distorting the top deck too much, I used plastic bags filled with water to hold the top deck down until the J-B Weld cured.

 

After everything was cured, I used a band-saw to rough cut the edges of the excess cloth and then a sander to clean up the edges. Using my insert template, I drilled through (just) the top deck to expose the original insert holes.

 

Done.

 

So, how much weight did I save? Maybe a 1/4 of a pound. The PVC cores are already very light!

So, how did it ski? It was so stiff that it had absolutely no "feel" through the feet and had zero shock absorbancy.

Was it worth it? See above comments. I think that you can figure that out for yourself.

Would I recommend anyone else trying it? No, but it was still fun to try it.

 

 

If you have any questions, just ask.

Chuck Illi

 

@Horton and @MattP: Yep, my wife couldn't understand why I wouldn't want to make and sell them myself. "Don't you want to make money?" All of the time I was thinking "Hmmm, Horton and Carbonfins".

 

@MattP: I checked the wing idea you proposed. Unfortunately, there isn't enough wing material to work with to get the dimensions required. See my separate e-mail to you.

@Than_Bogan: Very light in comparison to anything I have previously encountered. I don't have any values to quote. (I guess I will have to get out my old postage scale!)

 

@MattP, etc. With regard to the foam core waterski. No, I didn't melt it with heat, nor did I use acetone. Acetone will not attack a PVC foam core without also attacking the resin of the ski. Give me a day or two to write it up.

@Than_Bogan: Surprisingly, the "extra" material at the base of the fingers on a normal glove bunches up when you grip the handle. By removing this material it allows the rest of the fabric to displace and allows for a smoother surface in contact with the area of the fingers that normally develops the (torn) calluses. By using these gloves, I no longer develop the thick calluses that I used to have.

 

@BraceMaker: The earlier prototype gloves leaned heavily on the archery tab concept. The final gloves don't.

Similar to my thread regarding fin blocks, I'm not selling gloves, I'm just offering the design if someone wants to replicate it. I have been doing personal R&D for a number of years now and I'm starting to "divest" myself of some of my waterskiing related ideas that have passed their field trials. With regard to this glove modification, it has been in use for several years on several different pairs of gloves and tried/used by several different people (some well known, and some not so well known).

 

The driving force behind the glove modification was that I never wanted sore, blistered, hands to get in the way of going skiing. Like many others, on a multi-day ski trip to Florida, I once had to resort to the duck tape between the fingers and across the palm "solution" to sore/blistered hands. This just seemed ridiculous.

 

Some gloves are better than others, but I was looking for a different approach.

 

I started out by developing a somewhat simple R&D solution and having a very creative R&D engineer, and Nationals level competitor, try out the prototype gloves (Refer to Prototype 1 photo). The gloves solved the issue of sore hands, but introduced a different set of problems. The next step I took was to develop a very complex solution that ended up with a pair of prototype gloves being produced (Refer to Prototype 2 photo). However, at this point I had an "epiphany". I realized that I didn't need the complexity, I just needed a way to keep the gloves from bunching up at the base of the fingers when gripping the handle. A simple modification to existing waterski gloves is all that it takes.

 

The process steps for completing the modification involves turning a pair of gloves inside-out and removing part of the seams between the first three fingers (from the base of the finger to the first knuckle). Then, sewing the three fingers together back up to the first knuckle. The leftover material between the fingers needs to be trimmed and then re-sewn closed (reinforce with multiple stitches at the point where the seams intersect). It sounds a little more confusing than it is. (Refer to Final 1, Final 2 and Final 3 photos) On a new pair of gloves, after removing the existing seams, I was able to get to the point where I could convert one glove a night while watching TV. After completing the conversion, just turn the gloves right side out. Note: You will need the heaviest polyester or cotton thread that you can find, as well as an upholstery needle. I was able to get the thread from a furniture re-upholstery store. (Don't worry if you have never sewn before, as this isn't that difficult a project!)

 

I have had great reviews from users of modified gloves. However, the gloves have only been tested in the cold and (mildly) warm water we have in the Northwest, not the "bathwater" of Florida (for example), so your results may vary.

 

 

If you have any questions, just ask.

Chuck Illi

 

Sorry for the long discourse, but I wanted to be somewhat complete in the description.

 

I'm not selling fin blocks, I'm just offering the design if someone wants to replicate it. I have been doing personal R&D for a number of years now and I'm starting to "divest" myself of some of my waterskiing related ideas that have passed their field trials. Similar info will be released on a simple change to waterski gloves that was able to reduce/eliminate the potential for sore hands and ripped calluses. In addition, for fun, I will be releasing info on my foray into converting a foam core waterski into a hollow one, and my saga of developing various (unusual) waterski binding solutions.

 

With regard to this fin block, it has been in use for several years on several different skis (Refer to first photo) and tried by different people in the industry. The fin settings, once set, have been totally stable. And, as discussed in the D3 Rockerblock thread, the fin block will not change any existing tail rocker of a ski.

 

The driving force behind the creation of this particular fin block (more of a clamp, really), was the frustration with the, sometimes interminable, length of time it took to adjust a "conventional" fin block (think O'Brien/Elite). Typically, I would get one adjustment made and then it would have caused something else to change. After multiple iterations, I might get the setting I was targeting. So, I looked at what was out there, and what had been used in the past, and created what you see in the attached pictures. It separates DFT from Depth and Length and, more importantly, minimizes the changes between Depth and Length when these settings are changed - therefore, fewer iterations. I am able to set up a ski, from scratch, in approximately 10 minutes with this fin block (and that includes mounting it to the ski blank) It can take less than 5 minutes to make a small adjustment. (About 1 minute, if it is just DFT.)

 

The key to the fin block, other than it being simple and very light, is the slots used in the clamp (for DFT adjustments) and in the fin itself (for Length and Depth adjustments). (Refer to second photo for disassembled fin block) - The slots are cut in a manner to be just a few thousandths larger than the 8/32" NC machine screws clamping the fin and fin block. I decided to cut the slots just long enough to accomodate the typical adjustment range. But, this is not critical to its purpose.

 

The other important design element is the location of the aft-most slot in the fin blade. It is located such that the fin will pivot in an arc (where the radial begins in the center of the aft fin slot (Refer to third photo), that is very close to the arc/curvature of the bottom of the fin blade in this vertical location. This allows the Depth to be minimally or totally unchanged when adjusting Length. The forward most slot location is somewhat arbitrary. In this case, it allowed me to machine all four fin clamp pieces to be the same (other than being mirrored).

 

The upper exposed part of the leading and trailing edge of the fin is only slightly higher than what occurs with the same fin setting in a conventional O'Brien/Elite fin block. In addition, there are no sharp or 90 degree edges with any of the components (it might not look that way in the pics). I agree that there is a lot more "blade" exposed in the center section, but I would speculate that there are very few people who have been whacked by that part of their ski. In addition, it is no more sharp than the fin itself!

 

The shape of the fin clamp parts shown in the pictures are specific to the insert pattern of an O'Brien/Elite fin block. Ideally, new insert locations would be specified if this fin clamp were to be installed as standard. (I created a differently spaced, and more efficient, fin clamp that was installed on a ski that did not have inserts. The fin clamp is not shown, as it was given to Eddie Roberts for a separate evaluation.)

 

Adjustment process (new fin and clamp):

a) With fin block assembled, insert fin into ski and finger tighten all screws

b) Set DFT to match approximate final number (again, the screws only need to finger tight)

c) Set Length to match approximate final numbers (screws only finger tight)

d) Set Depth to match final number and lightly tighten screw with allen wrench

e) Set Length to match final number and tighten both front and back fin-to-clamp screws with allen wrench

f) Set DFT to match final number and tighten fin clamp-to-ski screws with allen wrench

g) Check measurements - If all are correct, ensure that all screws are tight

 

Adjustment process (for small adjustments):

h) If it is just a DFT change, then conduct Step (f) after loosening clamp-to-ski screws

i) If it is just a Length change, loosen front fin-to-clamp screw and lightly loosen rear fin-to-clamp screw. Rotate fin to adjust length (if you are careful, the Depth should not change) and tighten screws.

j) If it is just a Depth change, loosen rear fin-to-clamp screw and lightly loosen front fin-to-clamp screw. Rotate fin to adjust Depth and tighten screws. Note: There is a possibility that the fin Length will slightly change when changing Depth. Some iteration on (i) may be required. (An increase in Depth may very slightly shorten Length, and a reduction in Depth may very slightly increase Length)

 

It should be noted that the modification was accomplished using an O'Brien/Elite fin blank. Examination of the current RADAR fin blank, for example, reveals that the modification can't be accomplished as there is no fin material at the desired rear adjustment slot location. In this case, a new fin blank would need to be "cut" to replicate the RADAR fin shape and "ventilation" hole pattern.

 

If you have any questions, just ask.

Chuck Illi

 

@Wish - The upper exposed part of the leading and trailing edge of the fin is only slightly more than what occurs with the same fin setting in a conventional O'Brien fin block. In addition, there are no sharp or 90 degree edges with any of the components (it might look that way in the pics). I agree that there is a lot more "blade" exposed in the center section, but I would speculate that there are very few people who have been whacked by that part of their ski.

 

@SkiJay - The D3 reference to tail rocker is that the fin block will not change the pre-existing tail rocker of the ski, and it is also true for this design. With regard to this fin block, it has been in use for several years on several different skis and tried by different people in the industry. The fin settings have been totally stable.

 

@Horton - One of the industry people I refer to, above, is a common friend. Try it, you'll like it.

 

The reason I designed this fin block was not to address changes in fin rocker. (I have not seen a carbon fiber ski that will flex significantly in the last 8 inches.) I designed it to reduce the time necessary to make fin setting adjustments. I too had suffered the interminable length of time it took to make changes to fin settings with the conventionally designed fin block. So, I designed this one. It separates DFT from Depth and Length and, more importantly, minimizes the changes between Depth and Length when these settings are changed - therefore, fewer iterations. I was able to set up a ski, from scratch, in approximately 10 minutes with this fin block (and that includes mounting it to the ski blank) It could take less than 5 minutes to make a small adjustment.

 

But, all of this will be moved to another thread. This thread is about D3, so please hold any more comments until I get the other thread started. (Oh, and I'm not selling the fin blocks, I'm just going to offer the design if someone wants to replicate it.)

I will be discussing this fin block in another thread (soon), but I wanted to show that there are other ways to keep the fin block from changing the natural rocker of the ski. But, as @KM said "Can't they just rocker the bottom of the ski and keep the top of the ski where the fin clamps on flat?" Yes, at least in the case of O'Brien, it is definitely a consideration when the ski is designed.

@DanE

Correct - the snow ski analogy made by D3 doesn't make sense. In powder, a powder snow ski with rocker will still have the same area to help with flotation as a ski without rocker. On packed snow the rocker will reduce the area of the ski in contact with the snow, thereby making the ski "appear" to be shorter. However, a waterski is always immersed at the tail, so rocker will not change the apparent length of the ski.

 

Oh well, marketing holds a place in any commercial product.

More curvature (in profile) at the tail = More suction at the tail. Yes, it will help the ski come around in a turn, but it will also increase drag cross-course. This is always the same balance that plays out with wing angle settings.

 

I guess I would prefer to "play" with fin settings, rather than to add (a very difficult to quantify) adjustment in tail rocker adjustment. The @Mateo Vargas comment is not that facetious.

Another form of boot release. These were a set of step-in bindings I created in the fall of 2011. The release springs were a laminate of fiberglass and carbon (as were the custom molded boots).

 

I learned a couple of things when I first tried these bindings. But, basically, I don't ever want to have boots that release independently of the front and back foot (single plate, please, or if one releases so does the other). I had an interesting toe release of the front foot as I was going through the wakes, but the back foot was still attached. The landing was not pretty!

 

I have shelved them for now, as I am happy with my (fixed mount) custom bindings that I have used for about 4-5 years.

 

With regard to the releasable cuff. O'Brien (Adam Cord) was developing the same concept for the Elite bindings. Unfortunately, he hadn't completed his R&D work prior to his departure from O'Brien. He would be a good source of information regarding the design requirements for the cuff hinge/tension pin, as he used himself as a "guinea pig" for the test bindings.

 

Chuck Illi

With respect to O'Brien and Elite skis, I would like to add this info to the discussion - At the time that Adam was working there, he had access to a fantastic waterski test team (Andy, Glenn Campbell, and sometimes Drew Ross (health issues)) to get design feedback. He also had great support from his immediate superior, Pete Surrette. But.... Adam was responsible for preparing the brochure and marketing info for all of the O'Brien waterskis (Jordan Bollard was his one person art "department" that pulled everything together), designing and coordinating with China on the production of the waterski boots, gloves, and vests, designing the tooling for the RTM process and coordinating its development (from scratch), and if that wasn't enough, he personally ended up building most of the Elite skis for the first year and a half of production (for which he had no say over market pricing). Why was he spread so thin? Wakeboarding dollars vs. waterski dollars.

 

With AM Skis, he only has to focus on engineering/designing (and, at least at first, building) slalom skis.

 

With Andy as his business partner, you know that they won't be spending any time on wakeboards!

 

I know that Adam is in good shape, but I'm guessing that he is only holding the bottom molded carbon form/sheet of the ski. Great shot, though!

MattP...

 

Where did you find the "album" of Marion Mathieu pics that included the one you attached to this thread?

Which lake are you referring to in Abbotsford? Mill Lake, or?

"A" please