Paul,
I spent 6 years on submarines, they use the red=off=closed(valve)=open(bkr) convention. Almost all indicators are illuminated so that even in the "rigged for red" environment they are still easily identified.
That was the US fleet, I am just guessing, but I assume the the "uk" at the end of your moniker stands for United Kingdom?
I only had the pleasure of visiting one British submarine, and while it was very interesting, I cannot recall the indication scheme.
In a side note I must mention that the sub that I visited was involved in "war games" with us and both of our surface forces. The UK is, frankly, frighteningly good at their anti-sub warfare. Side effect of being an island nation, maybe?
I have a great deal of respect for our "neighbors across the pond".
Big Ed
