The
term wishbone when used in spearguns, for spearfishing refers to a
stout, U-shaped metal rod to which the tubular band material is
fastened.
The band material can be quite stout and pulled back in a double loop to several times it's relaxed length. An attachment to the band-end needs to be secure or the connection could slip when pulled and snap. It can be a painful and dangerous lesson if the band pulls out of the wishbone. The diver's hands are at risk if there is a failure. Quality technique is needed if you tie your own bands or better still, or purchase commercially made bands. What I am showing you here is just a suggestions. Divers who make their own spearguns will often tie their own bands. That way they can get the power they want from the rubber. Many divers use 'rope' wishbones. These lay parallel to the spearshaft, whereas stout metal wishbones hold their shape and spread the bands slightly away from the spearshaft. My personal preference is to use high quality metal wishbones made by Masahiro Mori in Los Angeles, CA. Riffe International sells premade bands with rope wishbones for their spearguns.
Please see the image below as it illustrates how metal wishbones are inserted into the inner bore of speargun rubber.
The band material can be quite stout and pulled back in a double loop to several times it's relaxed length. An attachment to the band-end needs to be secure or the connection could slip when pulled and snap. It can be a painful and dangerous lesson if the band pulls out of the wishbone. The diver's hands are at risk if there is a failure. Quality technique is needed if you tie your own bands or better still, or purchase commercially made bands. What I am showing you here is just a suggestions. Divers who make their own spearguns will often tie their own bands. That way they can get the power they want from the rubber. Many divers use 'rope' wishbones. These lay parallel to the spearshaft, whereas stout metal wishbones hold their shape and spread the bands slightly away from the spearshaft. My personal preference is to use high quality metal wishbones made by Masahiro Mori in Los Angeles, CA. Riffe International sells premade bands with rope wishbones for their spearguns.
Please see the image below as it illustrates how metal wishbones are inserted into the inner bore of speargun rubber.
Note
that these are very nicely manufactured wishbones made by MORI. It is
not so easy to find quality products which do not easily fail. These
are the good ones.
The
string that I use is 80 pound test braided dacron fishing line. Other
people use different materials to make the ligatures to fasten the band
material to the wishbone. Note the bulge in the rubber. You must fasten
the ligature behind the bulge formed by the ball on the wishbone.
Tighten the ligature. The knot is a clove hitch. It can be pulled quite
tight and compresses the band material to a diameter where it will not
slip past the ball of the wish bone. You have to pull very tightly, so
be very careful to not allow the dacron line to cut into your fingers
in the process. If uncertain, use gloves when you pull the line tight.
I always do a couple of clove-hitch knots, one on each side of the band
material for extra security. Additonally, I put a drop of
thermoplastic glue over the knot and slide a collar of electrical
heat shrink tape over the knot. When you warm the heat shrink with a
heat gun, it softens the glue and bonds it to the cord and heat shrink.
This assures the tag ends will not come undone. It gives a professional
appearance.
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