"...it was the failure by a few R/Os to copy Safety (TTT) nav warnings after the old silence periods that led to the famous 1970s disasters when ships ran full speed into wrecks in the English Channel that led to the introduction of Navtex."
Huh? I never hear that one before.
As far as I'm aware, Navtex didn't come out even experimentally until about 1990, so it was a pretty slow response.
My only experience of Navtex had reems of paper being spewed out giving warnings for the Atlantic to ships in the Pacific. It all ended up in the rosie.Hope they sorted that out!