Blue Water Hunting and Freediving - Digital Version 1 - Page 91

gear fracture
This detachable head was fractured at its weakest point .
two-thirds on the other . ( Exclude any welded tab areas , as these are frequently bent and are best treated last .) Check the final results on the slit lamp with V-blocks supporting each end of the shaft .
Make sure the barrel is perfectly straight . It should not bend excessively when fully loaded . You can test the amount of bending by measuring the straightness of the loaded shaft . Load the gun in the water and run a string along the top of the shaft . For safety , never take the loaded gun out of the water , and make sure that the gun is equipped with a safety that positively jams the sear lever in place . Any bow producing less than 1 / 8-inch ( 3 millimeters ) of daylight between the string and the shaft is acceptable , but the less bend the better .
The amount of trigger pull affects accuracy . Surprisingly , trigger pull ( the amount of finger pressure on the trigger required to discharge the spear ) has a great effect on accuracy . “ Too little pull may cause premature firing before your aim is completed ,” Harry says . “ Too much pull causes jerking , which ruins your aim . A delayed release may result in a missed shot . The pull should be light enough that there is no recollection of it after the shot . It should be firm enough to provide some finger resistance when test firing . ( Six pounds is a good pressure .) The pull distance should be long enough to prevent accidental firing 1 / 4 to 1 / 8 inches , or six to ten millimeters .)”
The initial run of a tuna , estimated to weigh 300 pounds , shredded this 1 / 16-inch , 500-pound test cable . Interestingly , the braided and crimped end remained intact .
Managing speargun recoil is important for two reasons : safety and accuracy . Horizontal recoil is so powerful that in some cases , it leads to wrist injury . A lightly weighted gun ( about five pounds ), is unsafe when heavily loaded with power bands . Decrease wrist impact by selecting a gun with the handle angled back 120 degrees from the horizontal orientation of the barrel .
Also , recoil against an unlocked elbow can allow the barrel to smash into a diver ’ s face . Many divers have bruised or cut their heads . Recoil from a gun shattered one diver ’ s face mask and almost completely severed his nose . Fortunately , quick transportation to a plastic surgeon saved his nose . Another diver fractured a rib when he tried to control recoil with his chest .
There are three methods used by gun makers to control recoil . Water ballast — water-filled barrel cavities . Balanced rubber pull — roller guns using opposing rubber forces to neutralize recoil . Mass — relying on the mass of the gun to oppose rubber forces at release .