ROTFLOL!!! (Rolling On The Floor Laughing Out Loud)
My wife just came in to see if I had lost it. At least she did not catch me with my head in a tank. I think that would call 911.
Bertie, you get the "Pragmatist of the Year!" award for the simplest test and resolution, but one I would not volunteer to do myself, so would not suggest it either. My son, now in his 40s, did have a waterproof periscope that we used to take to vacations with us. It came from Toys R Us, but well over a generation ago. I no longer keep up with such things.
PP - IF this thread ever ends, please move it to The Best of the Rest! This is too good to lose track of...