This is George Sandals' home made polespear triggering device. Take a look, I'm going to try this design but may use a different collar at the spearhead end. My use would be for small rockfish in the 1-3 lbs. class or Lingcods.

I have been looking for this trigger idea for years and this design looks good. I/m not sure but I think I saw the triggering handle back during the 1980's that was made of red/orange plastic and had a button that held pressure on the fiberglass pole spear shaft. It wasn't very safe as it would tend to fire off if you didn't keep your finger on the button to hold the shaft in place.