My folks had a place in Two Pines Trailer park back in those times and we would go out SCUBA diving. There were piles of beer cans, in pyramids, in certain areas. It amazed us back then how they could come to the same location year after year, well before GPS. The debris (nice word for litter) had varying degrees of silt and junk on them. Probably just did a good job with the compass and landmarks on land. Bottom line (no pun intended), Samiam is correct. There are pyramids of cans and bottles on the bottom that I am sure today look like boulders on a fishfinder.
