I'm a bit late to the thread but I love it, thank you. I can answer a few qs.
PP asked why it's GBR not GB. All countries have a three letter code. Interestingly some use the Anglicised version e.g. GER for Germany, but some use the native spelling e.g. ESP for Spain. No idea how that's decided.
Also a pp asked about if boats are transported or borrowed. Rowing boats are transported. The singles, doubles, pairs, quads and fours are all taken "whole" in shipping containers and the eights, which are about 19m long, split into two sections.
GB didn't have the same cox in the men's and women's eights. They are an integral part of the crew and will train and get to know their crew inside out, what motivates them and what their race strategies are. I doubt that doubling up would have been possible anyway even if permitted because the men's race started when the women had just finished. It wouldn't have been possible to be in two both at once. What GB did have this time, was that the women's cox was a man for the first time ever and he had previously coxed the men. As with all of the athletes, the best person for the job is selected.
There is never a podium at rowing events. It's a great q and they could make them big enough, but they are almost always on a pontoon and the rowers pull in, receive their medals and row off again to take the boat back. It's a bit different now as they are all getting changed into those awful tracksuits and I couldn't work out where they are coming off the water and if they have to get back in the boats. I don't think so.
Why do rowers row backwards? It's because our strongest and biggest muscled are in our bums and legs. Much stronger than our arms. So a rowing stroke is actually pushing ourselves away in the water rather than pulling with much weaker arm muscles.
My q: how does the ball get placed back in the centre of the pool for each water polo restart?