Okay, I”ve read through this thread, and can say that I’ve only lost my mask once, and that was when I was rolled (with my buddy) by a 20 foot (about 6 meter) wave off the Oregon coast. But that was the least of our problems, and we waited outside the surf zone, and were picked up by the U.S. Coast Guard about 3 hours later. We had no backup masks, but since we were on the surface, that was no problem.
I used a backup mask only under one circumstance, and that was when I was using a full-face mask with my double hose regulator. I carried a second mask on my upper arm (left, I think) with the strap around my arm. While I never had to use it, that was simple and worked at a time when our wet suits had no pockets (mine still doesn’t).
I am rather concerned about some of the newer masks. They have a plastic, rather than stainless steel, pin in the strap keeper, and I’ve seen several of these break. If you look at the older, oval masks, they always had a stainless steel strap keeper. Now, these are made of plastic, and subject (for some) to breakage. My current “go to” mask is a TUSA, which seems not to have a plastic pin (it’s hard to see as I have a
SeawiscopeEY on top of it).
The 5 photos below show the evolution of dive masks. The first is a White Stag oval mask, which is over 50 years old and still functional. Note the stainless steel strap keeper. The second is a much more recent Scubapro 3-window mask, with a plastic strap keeper, but note that the pins actually holding the strap are stainless steel. The third photo shows a completely plastic strap keeper. The fourth photo shows a mask where this plastic strap keeper has broken. I added the TUSA mask I use all the time, photo #5, and it does have a stainless steel pin holding the strap.
The U.S. Navy constantly in their Underwater Swimmers School stated that the only place for a mask was on your face, not your forehead. So if my mask is on, it’s usually on my face. (In the U.S.S., if one of us had our mask on our forehead, “Mike Nelson style,” he would need to give 25 pushups to the instructor, and carry a “buddy line” with him the rest of the day—it’s a 3-inch thick rope about 6 feet long, and we would have to sleep with it too).
SeaRat
PS, I collect dive masks.