The more experienced spearos surely know this, but beginners might not, and so how is it possible to make a simple cover for a prong?

Prongs are usually sold with a black plastic cover for the tines. Often though such cover comes off by accident and is lost. How can we make a new one of our own, even better than the original? Just like for the harpoon, take a long enough piece of elastic band for sling guns and fit it on the two sides on the external tines of the prong. That is it! The tines are all covered and safe and the new cover will no more come off just by chance.