1. They certainly did not decline in the 80ies.
...snip...
But if we fast forward to 1992 we see that the German team for the double wihout Cox is West German. The time set by the UK couple in 1992 seems to be the fastest olympic times until 2004, but the data I dredged up is lacking, nor do I have any idea of any conditions of all those years.
Toward 180mmCrank:
All in all a miracle. I will not contest this particular case as I do not know enough about rowing, it's way in the past and (most importantly) you clearly have the better data and thus certainly have my ear.
But I am adamant that your statement "we wouldn't know where to start if we even wanted to dope" is hyperbole.
You might not have known, but I do know enough about (university) rowing (especially in those years) that this simply is nonsense. Rowers are very well educated people and smart enough to figure it out