This was the one about manoeuvring to maintain a safe operating envelope i.e what to do if planes jam at high speed or sub floods a low speed.
A lot in the lecture about control of subs - effect of control surfaces, pitch angle etc. It was also nice to know that not everything is predictable by computer they use models extensively in test tanks and also free running in a reservoir to test and characterise hull shape etc.
My thanks to David J for letting me know about this lecture series.
Also I imagine that not many reading this are "just happening to be driving past Barrow" but next week the lecture is about the rescue attempts on the Kursk. I see other submarine lectures in the coming weeks.
They are free and open to the public.