Roffenon February 14 2012 00:02:42
Read vertically, whites are dots and greys are lines. E.g. "R" is dot-line-dot.
Vuzmanon February 14 2012 10:34:12
"Useful" is debatable, but if I were a submarine captain during WWII I would think this was pretty sweet.
Laluuon February 14 2012 11:01:11
If you were a submarine captain during WWII, you'd probably have no need for it, since you should know the morse alphabet by heart. Also, when telegraphing and such, the letters come so thick and fast, that you wouldn't have time to look them up on the chart.
But I have used it extensively in the past, during my scouting years.