Sigalsub as company specialized in the design and production of machined metal components, has a great line of wishbones from which to choose, different models, materials and dimensions give the spearo the opportunity to best tune its speargun. All wishbones are available in the solution with Delrin plugs.
Metal arch wishbones: XL & Jewel-ML
With a tough design, these wishbones are thought for use on all types of shafts, from shark fins, to pins, to notches. They differ in material, Steel or Titanium (named Energy), and in dimensions, the latter determining a different position of the rubber bands (wider or narrower). Wider elastic bands generally mean they are positioned more parallel to the shaft and so determine slightly better effeciency of the shot. Moreover keeping the two ends of the band open where the wishbone is determines a clear line of aim. Titanium reduces weight, which gives, even though extremely small compared to the weight of the shaft, a better accelleration of the shot. In fact, if weight of the shaft on one side reduces acceleration of the shot and on the other improves inertia, meaning it penetrates the fish with greater force, differently the weight of the wishbone has totally no positive aspect, but only the negative one of reducing acceleration. Moreover, especially on wooden spearguns, the metal arch wishbone can hit the wooden muzzle and dent it. A lighter Titanium solution will definately reduce this aspect.
The dimensions of the metal arch wishbones go from the widest (XL), 52.66 mm, to the smallest (Jewel-ML), 37.67 mm, both add the “Energy” indication when made in Titanium.
Metal blade version – Classic
Another version is the metal “blade shape” version, named Classic. The Classic has an even smaller width compared to the Jewel-ML, and equal to 24.26 mm. This solution is particularly adequate for shafts with notches.
Metal wire arch version – Wire
Another solution is the metal wire arch version, the Wire, which is surely lighter, but evidently less resistant. Still the wire can be substituted easily, without changing the entire wishbone. The width of the metal wire arch version is 33.57 mm, but this value must cosider that the wire will frex under the load of the elastic bands and will most probably reduce the width to a value which will be equal or even lower than the metal blade version.
Dyneema line – Sphere & Loop
Final solution is the simplest solution with olives and Dyneema line, in two different versions, the Sphere, with double dyneema line arch, and the Loop, with eyelets to which a piece of dyneema line is connected, creating an easy solution to subtitute the line each time it wears out. This solution has the advantage of reduced cost and weight, but the limit of having the bands not parallel to the shaft and barrel, but with a small angle that could reduce efficiency of the shot. Also, this wishbone gived no distance to the bands, which come to contact one end to the other of the band and close the line of aim on the shaft, making it more complicated to aim the shot.
As recap, in the following table the measured widthes (in mm) of the different wishbones:
As said, weights of wishbones can make some difference in theory. On one side the lighter they are the less weight has to be pushed. Still a steel shaft can weigh around 365 grams for a 140 cm long and 6.5 mm diameter double barb with shark fins solution. The difference between the lightest wishbone, the Dyneema line (4 grams), and the heaviest, XL with plugs (25 grams), is 21 grams, equal to around 6% of total weight which can be a relevant percent, but which decreases to 8 grams and around 2% of total weight when moving from, for example, an XL (18 grams) and an XL Energy (Titanium, 10 grams). On the other hand a heavier wishbone can determine more damage to the muzzle in case of hitting it, especially with wooden ones. Definately solutions with caps weigh more.
For a complete presentation of Sigalsub wishbones line, and for your our curiosity, below table indicates weights (in grams) of the different wishbones.