Those nails look like they were set using a explosive powered nail gun and then the heads were cut off...
This is incredible. I shutter to think what that would do to some teenagers tubing down the river in summertime.
"While the fishing guides aren't as rabid as the white water rafters and kayakers about claiming the rivers as their private domain they all have a hate for any industry that may use the same territory and have supported each other."
Some of the worse harrassment I have had as a fly fisher has come from the enviro white water rafters. Most kayakers wait upstream until you wave them down. I have been knocked down by the water rafters without any warning from them. They are like the concrete truck drivers who get paid per load. God help anyone who gets in their way as they head down stream.
"Those nails look like they were set using a explosive powered nail gun and then the heads were cut off..."
That is what they appear to be. Those nail guns make a lot of noise and one big enough to drive those nails in would be really loud.