Vulcan Sheaths seem to be as rare as jellyfish teeth, so I had to fabricate something to make my knife useful. It took way too much time, and not really identical to the original, but at least I can go diving with it.
I am grateful to Dale for providing some measurements from his original sheath to help me get started. This one is about 1/8" wider than the original to allow a stronger assembly, but the length is pretty close.