Fishtailing and Porpoising Arrows

QandA logoI got this message just a few minutes ago. I responded directly but thought you might want to see the interchange, too.

A couple of years ago I was placed in charge of our NASP Archery team at my school and have noticed a couple of issues that I wanted to see if you had any advice about. Both involve the smooth flight of the arrow.

Many times we see arrows fishtailing down to the target. I assume that this is caused by the archer’s release and its effect on the string. I feel like sometimes our students let that string drag off and maybe that is causing it to roll and create the fishtail. I wanted to see if in your opinion whether my thought was correct.

The second thing is a porpoising arrow, one that seems to wave its tail up and down while in flight. I cannot figure out that one at all. And I even have it happen to me sometimes. If you have any advice or comments on this I would really appreciate it.

***

Genesis Bow

You can see the nocking point locator (white on black string) is slightly higher than a line at right angle to the string and lined up where the arrow touches the rest.

The fishtailing you mention is due to multiple factors. If the arrows are flying fine and an occasional arrow fishtails, you are right—a sloppy release is at fault. A clean release allows for a great many other things to be slightly off, but is not a panacea. Contributing factors in fishtailing are many: centershot setting, arrow spine match among them. And arrow spine is never correct in any archery program in which the equipment is lent to the participants. This is because a student with a 21˝ draw may use the same bow and arrow as a student with a 29˝ draw when they should use radically different arrows. The “Genesis arrow” is a 1820 aluminum arrow (18/64˝ outside diameter—20/1000˝ thick aluminum walls) with a spine of roughly 0.600˝. The only thing making these arrows way too stiff for archers shooting a 20# (max) bow with a short draw length is it is 29.5˝ long. The considerable “extra” length softens these rather stiff shafts a great deal and makes them “adequate.” The 0.020˝ wall thickness (basically the thickest walls you can get on an aluminum arrow) make them extremely sturdy, a real boon for youth archer programs. Getting a correct spine match for an archer requires a great deal of fiddling even after the correctly spined shaft is selected (of which the choices are myriad). Most of the fiddling is with the length of the shaft. So, the “spine match” for your NASP archers is “iffy” at best. Often only a slightly suspect loose of the arrow can cause considerable fishtailing.

Bow Squares

A bow square is the preferred tool for checking nocking point location.

Note One of the problems we have with beginner’s classes is expectations, primarily the expectation that anyone can shoot at all well with borrowed equipment. The ones who can probably have physical measurements (primarily draw length) which give them a better spine match than most.

The porpoising, in our experience, has always been due to an incorrect nocking point position (typically too low), this leads to the arrow leaving the string “nock low” and the nock or, more likely, the vanes of the arrow clipping the rest or the arrow shelf on its way out, giving you large up and down oscillations. Often the arrow shelves on these bows have many scuffs on them (left by previous encounters of vanes with the bow) and you can’t tell whether any of them are new. Keep those shelves cleaned off if you can (I use a Scotchbrite scuff pad). A clean shelf with a scuff mark left by a vane hitting it is a clear sign of a “clearance problem.” Clearance problems stem from nocking point height, centershot (arrow rest) misplacement, and arrow spine issues.

The bottom of the nocking point locator, should be roughly 1/2˝ above a right angle from the string to the arrow rest (mimicking the bottom of an arrow sitting on the arrow rest). Lower than that is asking for such problems. This is a primary use of a bow square (see photo), one of which I hope you have. If not, you can use the corner of a piece of stiff paper to find the point that forms a right angle to the string and touches the arrow rest, too.

Let me know if this helps.

Steve

 

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1 Comment

Filed under For All Coaches, Q & A

One response to “Fishtailing and Porpoising Arrows

  1. Pingback: Fishtailing and Porpoising Arrows | My Archery Experiences

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