Split Fin Physics

[Bubbletrubble]

SPLIT-FINS - SPLIT-FIN TECHNOLOGY has several illustrations that illustrate the method that produce thrust and force with split fins. These illustrations have been posted a number of times.

@mdb: The marketing information on the website isn't clear at all on the physical principles of the design. There's a diagram comparing it to a propeller but the vector forces acting on the fin blade are not explicitly depicted. Is that the best, most detailed rationalization of split fin technology available?

 

[mdb]

Bubbletrubble: Thanks for the question.

Here is a 57 page link to one of the patents:
High efficiency hydrofoil and swim fin designs (US5746631)

If you search Nature Wings patents you will find a lot more information.

 

[Blackwood]

Hmm, while I am genuinely interested, I can't see myself paying 125 bucks a month to read the patent.

 

[Bubbletrubble]

Bubbletrubble: Thanks for the question.

Here is a 57 page link to one of the patents:
High efficiency hydrofoil and swim fin designs (US5746631)

If you search Nature Wings patents you will find a lot more information.

@mdb: Thank you for the link. As Blackwood points out, the information cited is not available free of charge. I have three more questions:

1. Why doesn't your company make this information freely available?
2. What are the academic credentials of Peter T. McCarthy, listed as "inventor" on the 1998 patent documentation?
3. Has the original patent on the fin design already expired?

Thanks in advance...

 

[Blackwood]

A patent lasts 14 years, so it is covered until 2012, at which point my friend Mike assures me that the world is ending anyway.

That said, patents are flimsy things. You can get around them by offering up an improvement. I could pop a hole in the natures wing design and if I came up with some justification showing that it improves the design, I could (I believe) build it with no consequences and apply for an associated patent of my own.

 

[mdb]

I would suggest that you contact Nature's Wing since they hold all the patent information.

Nature's Wing Fin Design, LLC
2075 Belgrave Ave
Huntington Park, CA 90255 USA

Phone: (323) 227-0906
Fax: (800) 710-0270

 

[Bubbletrubble]

I would suggest that you contact Nature's Wing since they hold all the patent information.

Nature's Wing Fin Design, LLC
2075 Belgrave Ave
Huntington Park, CA 90255 USA

Phone: (323) 227-0906
Fax: (800) 710-0270

@mdb: Did Nature's Wing Fin Design, LLC, file for bankruptcy? A Google Search reveals a Feb 2008 legal dispute between patent-holder Peter T. McCarthy and trustee(s) of Nature's Wing Fin Design, LLC. Apparently McCarthy was suing to retain legal rights to the fin and wing patents from the bankruptcy estate. The value of the two patents was estimated at $1.2 million.

Thanks for the info.

 

[mdb]

You will have to check with Nature's Wing on all that drama.

We just concentrate on manufacturing the best fins with the best materials.

 

[Bubbletrubble]

With regard to the split fin patent, I read somewhere that Bob Evans (Force Fin) was the first person to come up with the split-V design...but the "full" split fin was patented by Nature's Wing which employed Peter T. McCarthy (patentholder on record). Does anyone know if there is any truth to this? I see this as relevant to the design "genealogy" of the split fin.

 

[reefduffer]

Hmm, while I am genuinely interested, I can't see myself paying 125 bucks a month to read the patent.

I'm mostly just lurking and eating the popcorn.

I got an A in undergraduate fluid mechanics, but that was 40-odd years ago and not my professional area. However, I can contribute in this one little area; the full text of all US patents are available free on the Patent Office website.

Go to PatFT » Page 1 of 1
Select "quick search", put the patent number in "Term 1", and select "Patent number" as Field 1. I linked to the starting point so that you can see there are other ways to search. For this particular patent, see the search result:
United States Patent: 5746631