No cold-water animal cruelty here, just some interesting film material featuring some of R. J. Mitchell's finest designs - the Supermarine Seagull V, it's more popular sibling the Supermarine Walrus and finally the Supermarine Sea Otter.
This film compiled by 'Bomber Guy' on YouTube from newsreels gives a great overview of the story of the Seagull V and Walrus. It starts off with a brief slow-motion shot of the prototype Seagull V being fired of Farnborough's catapult. This is the sort of material you'd like to be able to incorporate in books.
Thanks to Dave Homewood, I was introduced to this more comprehensive bit of instruction film for the RN chaps responsible for firing the ship-borne catapults. (Incidentally, there are a couple of other items later in this clip.) In this case, this is on a smaller training ship in calm waters - I can't believe the routine was as deliberate as shown here when they entered battle!
Note that the aircraft fired off is a Supermarine Walrus and what lands back allongside is a Supermarine Sea Otter - if memory serves, the prototype in pre-war colours, while the film is dated 1940. While the aircraft are very similar at a glance, they are completely different designs, and the easy difference is that the Walrus has a pusher engine, while the Sea Otter's a tractor set up. Once you notice...
Dave wondered "Do you agree that the catapult officer overseeing the Walrus launch who is glimpsed very quickly in the first film is perhaps Sir Michael Hordern? I'm sure it's him, and I know he was in the RN in WWII and was already an actor by then, so maybe he was roped in."