Thanks for more interesting history on the development of spearfishing gear Sam.
As you mentioned, the 3-Prong tip is very often referred to as a paralyzer tip. My understanding is that as the tip penetrates the fish (hopefully the head) The prongs are spread apart progressively. When the forward motion of the tip is stopped, the 3 prongs are stretched out away from each other (to some extent) and this does apply a squeezing pressure which help to hold it in place and often immobilizes a fish - to some extent.
The video shows the use of a paralyzer tip on large fish when propelled with a Carbon Fiber pole spear. If fish that size are going to be specifically targeted, most people would select a slip tip over a 3-prong paralyzer tip.
As you mentioned, the 3-Prong tip is very often referred to as a paralyzer tip. My understanding is that as the tip penetrates the fish (hopefully the head) The prongs are spread apart progressively. When the forward motion of the tip is stopped, the 3 prongs are stretched out away from each other (to some extent) and this does apply a squeezing pressure which help to hold it in place and often immobilizes a fish - to some extent.
The video shows the use of a paralyzer tip on large fish when propelled with a Carbon Fiber pole spear. If fish that size are going to be specifically targeted, most people would select a slip tip over a 3-prong paralyzer tip.