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Post by mossback on Dec 13, 2005 10:20:01 GMT -8
Hey fellas,
Not to give a plug for the so called King, but there's an old Elvis Presley flick (called easy come, easy go) that has some pretty good diving sequences.......twin tanks, double hoses, looked like Voits and DA's with navy mouth pieces, , duck feet fins, etc. '
I just watched a few minutes of it as it started but had to go feed my horses........looks like it might be a good diving movie.......under water treasure etc. despite the bad acting.........
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Post by SeaRat on Dec 14, 2005 20:50:17 GMT -8
I have another older pair of UDTs that are beginning ot come apart from wear. I was thinking to cut a split into the center removing the lower 1/2 of the center rib and leaving the remainder of the center rib in place thus producing a semi split fin.. I am then going to cut the two sections slightly on a camber or Vee to provide clearence between the two split sections. I am curious how this might do. When you make your "scoop" fins how do you attach the new material and what mateial are you using? I find it strange that a fin like the UDT that has a strong center rib would have any "scoop" action at all. I see the photos--thanks----I wonder how the new UDTs behave. While they are fairly stiff I do not think them to be a stiff as some of the Voit versions. I have a natural colored Voit version of the UDT, it may be gum rubber also but it to is beginning to fail--it is actually very flexible. Perhaps I shall modify them as well. I actually have been thinking to put a spring strap on them and get some more use since it is the heel strap that fails on a UDT first... Looking at those pics of the UDT in action it ocurrs to me that it may be the perfect scoop fin if it had been molded with no center rib--leaving everything else the same. I also still think a molded in bend line or flex line down the center where the current center rib sits would enhance the "scooping" effect. I think I suggested that earlier many posts back but don't know if you caught it. James James, I caught it, but I'm not sure that molding the rubber is the way to go. It would have to be molded correctly, so that there was enough of a cup, and that would be difficult to mold and retain the ability to flip side to side. I have used two different types of materials. I have used a rubberized canvas material, and that worked very well. I am now using a high strength sheet liner material that a company called Orenco Systems uses for sand filter liners. It is a 30-mil PVC vinyl material, that they gratiously sent me from their scap pile. Here is Orenco Systems, Inc. website: www.orenco.com/catalog/PF31PT180.asp?pf=31I'll give Orenco Systems, Inc. a free plug as these folks are really nice, and I simply had to ask for them to send me the material. They make unique wastewater systems, that can be used anywhere (rocky areas, Hawaii, Alaska with permafrost, etc.), and have grown from a small family company to more than 200 employees. Here's their website: www.orenco.com/main_index.aspConcerning turning the UDT Duckfeet into split fins, that will work, but I don't think it will work as well as a scoop fin does. It will take more work to cut out the middle rib than if you simply start with a flat blade. Here's the photos of my current fins. First, this is the Plana Avanti, both with and without the scoop modification. Notice how much larger the surface area (and width, which was unintentional on my part, but works well) of the fin with the scoop modification: Here's the back of the same fins: Now take a look at my comparison project: These three fins have the exact same blade, the Plana Plus Graphite blade. They are all full-foot fins. But in one, I've made the split fin modification. In another (with the toe cut out--it had ripped and I needed this to ensure the whole foot pocket would not rip away), I have the scoop modification. The third is the original paddle fin flat blade. Here's the back side of the PlanaPlus-Scoop fin: Finally, because a lot of divers revere the Jet Fin, here is a comparison between the Lightning Jet Fin and my Plana Avanti-Scoop Fin: I used the same materials as the fin is made out of, the plastic from the blade. This reinforces the outside ribs, so that they are stronger and provide better thrust. They are first glued with Shoe Goo, then pop rivited with aluminum rivits. Take a look; we can discuss them later. John
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Post by nemrod on Dec 16, 2005 1:31:00 GMT -8
I got some of those Power Planas like those.
James
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Post by SeaRat on Dec 16, 2005 23:51:47 GMT -8
I got into the pool on my lunch break today, and swam with the various PlanaPlus blade designs. I first warmed up with a 400 yard swim, then did three sets of 50 yards apnea (breathhold, underwater swims) for time with the three different fins. After that, I attempted to do three sets of 100 yard crawl, and was going to do three sets of 100 yard dolphin kick, but that did not happen. I'll explain below, but first the results:
50 Yd U/W Dolphin kick[/B]
Fin Type: Time 1. Paddle: 0:32.73 2. Split: 0:32.74 3. Scoop: 0:32.27
100 Yd Crawl[/B]
Fin Type: Time 1. Paddle: 1:07.88 2. Split: 1:12.29* 3. Scoop: 1:17.10?
*Well, on my first attempt at the 100 yard with the split fin, my watch came off my arm (held by a velcro band which gave way). My second attempt at this same swim resulted in no time being recorded, so the time shown is my third 100 yard swim with the Split Fins.
?My first swim, again I got no time with the Scoop fins; my watch did not record a time. The second swim with the Scoop Fin design resulted in no time showing, but when I looked at the watch, and hit one of the buttons, the 1:17.10 time showed. I don't know whether this was correct or not.
I discontinued the swims because it was getting late (back to work), and because I was getting tired (the real reason).
This experience shows why Dr. Grier used multiple swims on multiple days to get a range for the different fin designs. I will also be doing this.
Buzz, are you going to get wet?
John
PS--This was my last swim in my decade of the fifties.
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Post by luis on Dec 17, 2005 2:30:51 GMT -8
Happy Birthday John.
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Post by JES on Dec 17, 2005 5:12:54 GMT -8
SeaRat,
Happy Birthday!
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Post by SeaRat on Dec 17, 2005 11:14:04 GMT -8
Thanks all, it's a beautiful sunny day here, but about 27 degrees and a 25 mph wind. So I think I'll go to the pool again. By the way, #60 isn't all that bad--I seem to have survived a lot, and appreciate even more now what life gives.
John
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Post by nemrod on Dec 18, 2005 22:50:30 GMT -8
I am going to get some Apollo splits soon. I am positve that they will prove faster as have all the tests proven thus. All these statements about current and bla, bla are weird. The fins don't know they are in a current, faster is faster. Thrust and speed are not always the same thing, I suspect that Jets and UDTs will provide a more solid response at lower speeds and that the splits once up to speed would dust the other two. James
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Buzz
Senior Diver
Posts: 64
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Post by Buzz on Dec 19, 2005 9:05:00 GMT -8
SeaRat
Sorry....been out-of-pocket for a few days doing Christmas family things. Yup....been getting wet all last week ....I go to my local YMCA that has a heated indoor Olympic size pool to keep in shape.....lots of fun. Anyway....I decided to try an experiment with a couple pair of old Voit floating fins.....I had two sets. I split one pair (they do not have a center rib) which was easy. I used a hole punch just below the foot pocket to start the split then used scissors to put about a 1/4 inch wide slit in them down to the end. At the bottom, I cut about a 2 inch radius into the end of the slit so it wouldn't have a square corner. Then I carried both sets to the "Y" and put them to the test one at a time. I used traditional long slow power kicks with the unsplit fins and I used small fast strokes with the split fins. Without any timing, it was very easy to tell that the split ones were a lot faster.
Buzz
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Post by nemrod on Dec 19, 2005 9:43:28 GMT -8
What if you had used the same small, fast kick with both sets? Would there have been any dfference? James
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Buzz
Senior Diver
Posts: 64
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Post by Buzz on Dec 20, 2005 11:42:52 GMT -8
Nemrod
Short fast strokes don't make you go faster with paddle fins......Long slower strokes don't make you go faster with split fins. Split fins require the short fast strokes to put them into warp drive ;D
Buzz
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Post by nemrod on Dec 21, 2005 1:25:41 GMT -8
"Short fast strokes don't make you go faster with paddle fins......Long slower strokes don't make you go faster with split fins. Split fins require the short fast strokes to put them into warp drive " How do we know that. If one where to split a set of Voit Vikings and leave another set as supplied I think you could use the same fast kick. I always have. I have always used a flutter kick and not the "fromt he hips" kick. Yeah, stiff fins like UDTs don't respond to that type of kick and I use a wider kick with them but again as I mentioned way back, I thinkit is the legs moving into the slipstream that eventually counters the thrust. I don't doubt that some fins benefit from a wider kick but the Voit Viking/Skindiver fins just does not seem to fit into that catagory to me. I am going to split an old pair and put them head to head, Skindiver split vs Skindiver. I don't think this lap swimming is proving anything, I may be wrong, are you holding arms to the side? Are you swimming in gear? James
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Post by SeaRat on Dec 21, 2005 8:40:06 GMT -8
"Short ...I don't think this lap swimming is proving anything, I may be wrong, are you holding arms to the side? Are you swimming in gear? James James, I have more times to post, and will sometime over the holidays. But the main thing that they prove is that I'm a bit out of shape Basically, the way the swims go is to do multiple swims for time, on different days with different fins in the sets, and see if you can see a difference. When I swim, the 50 apnea is swam underwater, with a pushoff the pool edge using the dolphin kick, and a flip turn at the 25 yard mark. The whole swim is on one breath. Time was taken when my hands touched the pool edge. For the 100 yard swims, I used crawl stroke with a close-fitting Dacor mask, and a racing snorkel (Finis competitive snorkel). See below: www.aqua-gear.com/finis.htmI swam sets first using the crawl stroke, but breathing through the snorkle. I then swam sets using the dolphin kick only. As I said, I'll post the times later, but it really showed how tiring this can become John
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Post by nemrod on Dec 21, 2005 10:25:18 GMT -8
"For the 100 yard swims, I used crawl stroke with a close-fitting Dacor mask, and a racing snorkel (Finis competitive snorkel). See below:"
I imagine your in better shape than me by a long shot! BUT, it was not that long ago that I could do a crawl with my feet dragging way faster than any scuba diver or surface swimming skindiver would hope to swim. To much of the power is being produced by your arms. I think to be a better guage the swims should be fins only, arms at the side. If 50 percent of your power is coming from your arms then the thing your trying to measure is being reduced by half. James
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Post by nemrod on Dec 21, 2005 11:28:18 GMT -8
Over the Christmas break I will take a pir ofold UDT and split them half way up the center rib removing the lower portion of that rib. I will also split a pair of old SkinDivers. I will then,in Jan. swimthem UNDERWATER using leg power only while fitted with tank, double hose and mask. I will swim several circuits of the pool and have my wife time me. She will be thrilled!!! I will then modify the split fins into a scoop fin and repeat and then by the end of Feb I will hopefully repeat the test with my new UDT and best Skindivers. I will use my DA (that was for sale) and then I will also use the same attire and mask--no stupid snorkel. The swims will be totally underwater so as not to introduce surface breaking characteristics into the fins performance. I may also swim with a set of Force Fin Pros which I suspect will easily outspeed the others. Eventually, I will repeat with Apollo splits as soon as I decide which I like or if I really want some. No arms flapping, arms at side. I have some rubber neoprene sheet which may be suitable for the scoop fin design, I wil have to study on how best to do that.
James
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