Finally the guy would throw out the line in just the right spot and my dad would shoot the bobber.
That is a great idea. From my garden potting bench at our ground-level basement door, I can easily see both ponds, but it is extremely difficult to see the bench from the ponds. The scopes on my .22 and my 1100 fps .177 air rifle are both sighted in almost perfectly for the middle of both ponds.
The .177 would be ideal, as you can barely hear it shoot -- and probably can't hear it from the pond.
Be careful, but get law enforcement involved -- local and state game people.
I cautiously posted this story because I don't want anybody to get hurt. I eluded to the fact that my dad was in the service WW2, but forgot to mention why that was important. During his training, his markmanship was listed similar to/or as sniper. He was very good his whole life shooting. He actually was a twin, and they served together. He was ready to be shipped out via train to be be a tailgunner in a plane. The twin brother got sick with scarlet fever and held him back also so they would not be split up. Good thing, becuase I probably wouldn't be here today if he served in that capacity.
Just have to remember bullets richote off water!!!!!! Sometimes their poles weren't left behind at the water. They would run off without reeling them in and later we would come across the line in the woods and most of the time we could follow it to the pole.
Sorry for the Hijack SP. This will be the end of that story.