Here is the broken turnbuckle. It was a jaw/jaw turnbuckle which meant it had a t-shaped piece on each end to hold a jaw for the line and/or tang like you see at right above. The t broke off. Below you can see corrosion where it broke, the corrosion telling me it had been failing for a while, allowing moisture in. Whether it was a flaw from the beginning or a stress fracture I will never know. Might replace with the same or possibly go a size larger. Will have to think about that.