As I set here I have my Tiburon in hand. I can not respond as to the make up of the steel or its preformance in salt water.
I can tell you that the knife is held very securely in place. I can not physically force it out of the sheath with out lifting the release tab.
Also, not knowing the specific nature of your "how does the sheath work?" question, I will also make these comments. It is designed to be fastened to your personal flotation device. (PFD.) Assuming inverted carry on a PFD, it has "D" rings attached to both ends with velcro straps situated both horizontal and vertical. Hard for me to describe.
There is also a built in clip that could be employed on a PFD strap, however using the clip alone would not be as secure as I would like. I suppose it could be clipped to a waist belt or waist band in the inverted position, but it would be a bit akward to access the release, and not very secure using only this clip.
Hope this helps, and I would love to be more helpful if you have any other questions.