Setting up a speargun using either string or nylon line.
Many if not most spearguns require rigging and setting up prior to use after they have been purchased. Although the exact procedure can vary very slightly the general steps and methods are the same.
The speargun can either be rigged with a cord (string) line or a nylon/multi filament line that is stronger and less likely to degrade and break over time. I will start by describing the method for rigging the speargun with string or cord as this is the slightly simpler way that uses knots as opposed to crimps.
Remove the spear from the speargun. Thread the string/cord through the “eye hole” at the back of the spear. Tie a knot in the end of the line that is now sticking out the back of the spear and load the spear into the speargun.
Take the string and feed it out the end of the muzzle, then back along the underside of the speargun barrel. Wrap it around the release catch, and then back along the speargun barrel towards the muzzle. At this point depending on whether you are using a bungee or not, either tie the string or cord straight to the eyelet on the muzzle, or connect the bungee to the muzzle then tie the string/cord to the bungee. You need to make sure that the string does not have to much or little slack in it so that it stays in place prior to the gun being fired.
The method for using nylon line or filament is in general the same, however as opposed to tying knots we use crimps instead. These crimps are usually supplied with the filament line and can be crimped wither with a special crimping tool (ideal) or with a pair of grips/pliers.
Remove the spear from the speargun. Thread a crimp onto the nylon/filament then feed the nylon through the eyelet at the back of the spear. Now thread the nylon back through the other side of the crimp and carefully insert the spear into the speargun trigger. Adjust the crimp and nylon so that it does not obstruct the either the insertion of the spear into the speargun trigger or the loading of the wishbone onto the groove of the spear. Now snip off any excess nylon leaving a very small (1cm) tail and burn the end with a lighter to make a small ball on the end of the nylon. Get your crimping tool (or grips) and crimp the crimp closed.
Now run the line out of the muzzle then back along the length of the speargun barrel, wrap the nylon around the line release catch the back along the speargun barrel towards the muzzle. Again you can now either attach the line directly to the muzzle, or you can use a bungee. If attaching the line to the muzzle the procedure is the same as what we did with the spear. Slide a crimp onto the nylon; thread the nylon through the eyelet on the muzzle and back through the other side of the crimp. Adjust the slack in the line then snip off any excess line leaving a 1cm tail. Burn a ball onto the end of the line and crimp the crimp closed.
If you are using a bungee attach this to the muzzle then thread a crimp onto the nylon line, thread the line through the end of the bungee, thread the line back through the crimp, adjust the slack, cut the line to leave a small 1cm tail, then burn the end to leave a ball and crimp the crimp closed. These steps should allow you to setup or replace the line on your speargun.
Remember to check that all knots or crimps are secure and that the tension of the line is correct. If the line is to slack the line will not stay in place, and if the line is too tight it will be more difficult to put into place around the line release.