Modifying fins, cutting, trimming etc.
- Thread starter SangP
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Bob Evans
Contributor
Sangp, here I am in Richmond, Virginia ready to visit the U.S. Marines in Washington DC. The photo that is posted shows what I always state. Check out the water flow on the down kick and you can see the strings at a 90 degree to the direction of travel. Flat fins push more water off to the sides than behind you, http://www.youtube.com/forcefin2020#p/u/3/shQVnMkuU5I which makes no sense to me. Plus you have the fin hanging off your foot, which makes no sense either. And on the up kick in the photo you can see the strings just hanging down. The knee and foot are bend at angles that hurt making me want to cry. The center cupped area just flaps back and forth like a bad heart valve. Looks like a lot of work pushing water in the wrong direction.
LOL! Thanks for the info Bob, I couldn't figure out the details of the scoop fin too but I give it points just for being so unique.
I'm curious if you've made any fins with a pivot similar to the scubapro seawing nova? I'm trying to see if I can cut out a tiny dent on some mares fins to make the fin easier to use by a pivot method?
Regards,
SangP
PS, my gf works in VA and if I was there I'll love to hear more from you. I always liked your logo looks like the merlion here in Singapore.
http://en.wikipedia.org/wiki/Merlion
I'm curious if you've made any fins with a pivot similar to the scubapro seawing nova? I'm trying to see if I can cut out a tiny dent on some mares fins to make the fin easier to use by a pivot method?
Regards,
SangP
PS, my gf works in VA and if I was there I'll love to hear more from you. I always liked your logo looks like the merlion here in Singapore.
http://en.wikipedia.org/wiki/Merlion
Bob Evans
Contributor
SangP, The Pivot fin is a flat fin trying to arch like a original Force fin. When you make fin's out of cheap materials they do not flex correctly so by putting a bunch of notches you can bend the flat blade easier. The Pivot concept is not new, maybe Mr. Wilson can find the hinge fin made back in the 1940's. The pivot fin design reminds me of the trap door on the gallows, opening up and dropping the water. Plus the design still hangs off the end of your foot. Using hand cast Poly-urethane I am able to create a flex zone that travels the entire length of the fin blade and gives a quick recovery to the snapping action. I do make a Pivot fin called the OPS which allows you to pivot the fin blade into different shapes while in the water. The design is covered on our ScubaBoard site and youtube http://www.youtube.com/forcefin2020#p/u/0/SpTkpXIuyVI Yes I am aware of Singapore's merlion, and others from Ireland, Greece, etc. Our logo was created by the design team who handled the Olympics in Los Angeles. Thanks for our interest, Bob
Hi Bob,
Regarding putting notched into the rails of the quattro fins, can you give me some idea of where to begin like depth of the notch and measurements please? It's a pair I'm willing to experiment with so wrecking it is ok.
I have one of your original force fin excellerating fins and as I must be doing something wrong but I not getting the same speed or control as from some of my other fins. I would really love to figure out how to fin backwards and frog kick better in them.
Bob I'm curious, aren't you the original inventor of the nature wing split fin concept so why isn't your name on the patent?
Many thanks,
SangP
Regarding putting notched into the rails of the quattro fins, can you give me some idea of where to begin like depth of the notch and measurements please? It's a pair I'm willing to experiment with so wrecking it is ok.
I have one of your original force fin excellerating fins and as I must be doing something wrong but I not getting the same speed or control as from some of my other fins. I would really love to figure out how to fin backwards and frog kick better in them.
Bob I'm curious, aren't you the original inventor of the nature wing split fin concept so why isn't your name on the patent?
Many thanks,
SangP
David Wilson
Contributor
Well, Bob, I knew that all that research I did decades ago on fin patents, sitting in my local public library, scouring dusty tomes might come in useful one day.
I've just perused my folder containing the photocopies of the patent descriptions and found two that may be of interest. One dates from the early 1960s and relates to a fin with a pivoted blade. It's also available online with the original illustrations. Another patent reference, also from the 1960s, relates to a fin with a "scooping" blade.
I'm sure SangP will let me know if any of this information is also of interest to him. If so, I will elaborate.
Bob Evans
Contributor
Dear David, I remember seeing one pivot design that used a door hinge with a spring lock to stop the pivot point. When I get home I will check my patent files, but I think this concept was covered in a old Popular mechanics magazine. Do you have Mann patent (1960's) from Italy that covers the split fin designs of the other companies? I had a translation done of Mann's Patent years ago. I will post next week. Thanks again, best, Bob
Bob Evans
Contributor
SangP, I would leave your Quattro fin alone. Have you ever cut down a tree. Notching works quite well. Sorry to hear about the Excellerating Force Fin, your a rare one to be unhappy with it's performance. On the Split fin (coined the name) the others are Paddle Fins (coined the name) with a split. My patents cover a up curved fin with a split that provides power and recovery.YouTube - ForceFin2020's Channel
David Wilson
Contributor
SangP:
The pivot fin patent I had in mind was Pierre Auzols' 1963 "Swimming Shoe" patent, US Patent No. 3171142. The illustrations are in a PDF file downloadable from
Swimming shoe
More details, with further patents in the references, on the web page atSwimming shoe - Patent 3171142
Auzols also took out a British patent (BP 979288) in 1963 for his design, called "Swimming Aids".
As for your question about notching the Mares fins, I don't feel knowledgeable enough to respond. Bob recommends caution and I bow to his expertise. By the way, you may find that John C. Ratliff is a useful contact on Scubaboard. He has done some experimentation on split and scoop fins:
http://www.scubaboard.com/gallery/showphoto.php/photo/34851
Bob:
My public library had the British Patents on its shelves and also a directory to US Patents, but it didn't run to continental European patent office publications. Of course many inventors took out patents with foreign patent offices; both Corlieu and Churchill, the "founding fathers" of twentieth-century commercial swim fin design, took out British patents for their inventions, BP424353/BP613609 and BP568101/BP602230 respectively. Both men referred to their inventions as "swimming-appliances".
Hope this helps.
The pivot fin patent I had in mind was Pierre Auzols' 1963 "Swimming Shoe" patent, US Patent No. 3171142. The illustrations are in a PDF file downloadable from
Swimming shoe
More details, with further patents in the references, on the web page atSwimming shoe - Patent 3171142
Auzols also took out a British patent (BP 979288) in 1963 for his design, called "Swimming Aids".
As for your question about notching the Mares fins, I don't feel knowledgeable enough to respond. Bob recommends caution and I bow to his expertise. By the way, you may find that John C. Ratliff is a useful contact on Scubaboard. He has done some experimentation on split and scoop fins:
http://www.scubaboard.com/gallery/showphoto.php/photo/34851
Bob:
My public library had the British Patents on its shelves and also a directory to US Patents, but it didn't run to continental European patent office publications. Of course many inventors took out patents with foreign patent offices; both Corlieu and Churchill, the "founding fathers" of twentieth-century commercial swim fin design, took out British patents for their inventions, BP424353/BP613609 and BP568101/BP602230 respectively. Both men referred to their inventions as "swimming-appliances".
Hope this helps.
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