Anyone notice the boom shape and setup?

Re The Boom.
The whole idea is to get as much of the mainsail as close to the 'tramp' as possible. They guess the end plate effect is worth a 10 to 15% improvement. The only reason it doesn't go all the way back to the traveller is that there would be no way to get all the crew across the boat during tacks and gybes. The 'tramp' is not like we know. Its actually made of sailcloth, so its really a hard surface. End plate effect is why most passenger jets have winglets at the end of their wings. It just cleans up the flow massively.