The Hanging Chain

As I walked round the golf course earlier, I spotted this chain hanging from a tree. I thought it looked a bit odd, but maybe it served some purpose of which I was unaware.
I mentioned it back at the 19th hole and Dan the green keeper was overjoyed. He said he had been looking for it for months. Apparently they use it to tow another grass cutting machine if they get stuck in the mud. I told him where it was and I could even show him a photo of it!