I can read my SPG, I can get direction from my compass. I cannot read easily my digital computer and depth. But if I was all that worried about it I would use my SP 0-500 foot professional analog/mechanical gauge and it I can certainly read. I can tell the time on my analog watch as well. And, if I was swimming in a place with deadly jellies sufficient to blind me, I too think I would just keep my eyes closed and hit the silk. You do not need to read the numbers, you look at where the hands are.
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