It seems obvious that the polynesian sling as shown was used for the slower casts associated with short to midrange accuracy exercise.  I can't fathom what that bead would do to my index finger after a distance launch.   This is the reason I make my leather release tabs so small,  I've found that below a certain mass, they will not bounce back and bruise the index finger of my sling hand.


Regarding the Iron Palm technique.....I'm almost surprised that anyone still devotes themselves to it.  Speaking from experience....it's a fool's gambit, which severely detracts from the finer dexterity necessary for many a much more productive hobby and comes back to bite you later on.  I'm 'only' 38 and wish I'd never even heard of the  high kick, shishinken, shi-tanken, or the iron palm.

Somewhat ironic, it is, that some wish to earn the tiger's paw and end up later in life only being able to use their hands as paws, due to the inherent damage to the finer circulation in the digits,  crippling arthritis being foremost among them.

The truth in fact, is that the iron palm, like so many other ego induced defeatist strategies, has been proven time and again, to provide very little bang for the buck, so to speak.  


This is not to say that some of the legends afforded it, are not based in fact.  Just that such facts are, in the greater sense, trivial ones.


In our modern era,  practicing the art of leaning forward with one's head between the knees so that a lightning strike might enter the derriere and pass down the legs to the ground and miss the vital organs, would prove a more productive defense strategy and more likely to prove necessary than braving the 'thousand needles' torture of simply typing at the keyboard as a result of preparing for a moment that, should it ever come, would hardly prove satisfying.

Besides, no matter how punitive a measure is taken to 'harden' the hands and fingers......they won't come close to the stone resolve of a simple Yawara or Kubotan key chain, one's elbow, or any number of other more sensible tools for blunt force striking, than the, by comparison, delicate components that make up two of our most useful appendages.


English,  I implore you to pass on the iron palm.  Let's face it, Your ego can never be as large as mine once was.   And that is the dubious essence of the Iron Palm.


Peace,


TS


P.S.  How weird is this.....above when I typed "Shi-tanken" without a hyphen....an automatic "cuss check" must have activated because the word was consistently modified to read:  "Nutsanken".  Only after I hyphenated it, did it read correctly.  lol

(Sorry, funda_iucunda)
  Yeah, it seems like I should not proceed with this idea.  Iron Palm does sound slightly stupid, I suppose.  And besides, when would I need more strength in my hand than I already have?  Against boards.  And as Bruce Lee says, (lol), "Boards don't punch back."
 
  Back to slings:  it could be that the fibres are Olona fibres.  This is a plant with a fibrous bark, like that of nettles or fireweed, but growing about 7 feet in height.  Or indeed, sennit coconut fibres, "coir", is also a definite possibility.  But considering Olona was once used as currency in Hawaii, and that it was specially grown in plantations, Olona does look quite likely.  Then again, the coconut is called the "the tree of life" in most Polynesian cultures.  Could be either.  Looks like coir to me, though.

Coconut fibres it is.
  You know, I want to do my PhD at the university of Hawaii.  Good Chinese department.  Can't beat the location.