I also remember the barrels from my childhood! When we moved to Coney Island in 1956 they were still there, a line of colorful, striped, floating wooden barrels attached to a rope that went back to the beach. I really enjoyed playing on them. The rope was buried far up the beach and then attached to an anchor in the ocean located about halfway the length of the rock jetties. Every bay in the West End had them! You could cling to the rope or wrap yourself around the barrel. They were a lot of fun and you could prove yourself by swimming out to the last one.
I can't remember when they stopped installing them, maybe around 1960? There was talk that they gave swimmers a false sense of security and that inexperienced swimmers would swim out too far to get to the third one. Safety ropes were part of the Coney Island beach for more than a century, but the barrels seemed to have appeared sometime in the 1950s. Most likely they were discontinued to save money or maybe because of vandalism. If anyone knows the reason, please let us know.
We have very few photos of the barrels but the ones below from the 1950s give an idea of what they were like. Notice the three swimmers clinging to the rope! A sign on the lifeguard chair refers to them as "life lines," and tells swimmers not to "bathe" past the last one. They seem so much smaller than what I remember as a child. I remember missing them when they disappeared.