Twenty years ago I bought the house where I still live today in Quebec (way inland!) from a woman who had built it in the early 70's as a country-house when she was living in Bermuda where she and her husband had a yacht. She also raised German Shepherds.
When I moved in, I found in the garage a large wooden crate with breathing holes and a dog name painted on one side (Cara, Bermuda). I guessed she had traveled with her dog to spend some time in her country home. Next to the crate, there was what I understood to be a dog-leash made of a piece of whitish rope with an odd eight-shaped chrome hook at the end which I could not open, no matter how hard I tried. I left it hanging from a nail in the garage and over the last 20 years I must have tried 3 or 4 times to open that hook, to no avail. I had checked on Internet to see if I could find any dog-leash hooks that might look similar... I found nothing.
Yesterday, a raccoon had unhooked one of my bird feeders from a string that held it hanging from a branch-stub away from squirrels and raccoons. I therefore went to my garage, looking for a spring-loaded hook that would lock the feeder cable loop at the end of the string instead of the S hook I had been using. That is when I saw that unusual looking hook again, hanging from a nail on the garage wall! Since I had some spare time, I decided that, this time, it would be a make-it or break-it attempt to open it!
I took a magnifying lens and I examined it carefully : "Kungsors Yachtyard Sweden"! How did I not see these words before...? I rushed to the computer, Googled these key-words, and when I saw the third item that came out of that search, "unusual piece of marine hardware [Archive] - The WoodenBoat Forum", I had a sense that a Eureka moment was near : I quickly followed that link and... here was my hook in full display at https://farm4.staticflickr.com/3938/...814a9ccd_c.jpg
Since it came with a description of how to open it ("There is a spring-loaded button, that when pressed, activates the spring loaded lever. When the lever is open, the button remains pushed down, but when you close it, the button springs up, locking the lever in place until the button is pressed again to release it") I knew instantly that the problem with mine was that the spring-loaded button was completely stuck. Twenty years of idleness or more... nothing to be surprised of.
I immediately soaked it in a bath of rust remover for a couple of minutes, then I sprayed it with penetrating oil, and click... in went the button and open went the hook with a snap! A twenty-year mystery has been solved thanks to you, CrosbyStriper, and since you also wrote "Anyone ever seen this fitting or one like it before, and/or know where to get them?" I wanted to answer your post and let you know that yes, I have seen this fitting at the end of a dog leash (which I now understand was a piece of marine rope!) for the last 20 years and, now that I know that it has not only held a dog on leash but has also joyfully sailed around Bermuda, it will not return to its nail on the garage wall. Instead, I will keep it with a few relics on a shelf, you know, that eclectic collection of objects that have stories to tell. Every now and then I will hold it in my hand and depress the button with my thumb to open the hook and hear the snap. Then I will close it again, and it will tell me countless stories, some of which will likely start with "Once upon a time, the ocean was sparking blue..."
As for the raccoons, I will get something else at the hardware store tomorrow...