Do you remember a submarine series on the TV years ago called:
'Voyage to Sea the Bottom' (or something like that.
) It featured a sub with glass windows in the nose. When they collided with something, which they did with monotonous regularity, the glass never cracked, but water would spurt in from the deckhead.
They spun the wheel on a convenient valve and the water stopped. I too thought at the time that was one very handy valve.
Also when the sub surfaced it literally leapt out of the water and slammed down in a big splash. I thought to myself: I bet that's pleased the lads in the galley !!
