I think they are badly overpowered and heading down, both spi trim and rudderangle suggest so. But I think they was supposed to pass to the right of the mark in the background, which looks a bit difficult from that angle. Not sure tough..
To me it looks like crew has just come in of the wire to drop the kite (so needing to bear off) - otherwise crew would be out (and helm if struggling to make a mark)
I guess the loads on the mast are much larger going upwind with lots of downhaul, mainsheet and double trapeeze?
Different set of loads.
Upwind, yes you have compression from the main sheet, jib halyard and downhaul, but down wind, you have the kite pulling the top of the mast forward (and assuming you had no mainsheet tension, nothing to stop it keeping going. Upwind, you have the DH and mainsheet and jib compressing it. Pull the jib in Max, pull the DH max and sheet in max and then out on the wire and fly a hull. does the mast break - no becasue they are (fairly) static loads (they can only go so far as you can only pull the ropes so hard and then the hull flies). your load is limited by the mainsheet (you can olny sheet in so hard), the DH (you can only sheet in so hard) and the RM of the boat (the hull will fly eventually).
The kite can pull the mast and keep pulling until something fails(the mast), you can only sheet the mainsail in block-to-block and the mast should be strong enough to hold it. I've only ever seen masts break in 3 days
1, Spreader (or fitting) fails, mast folds at the spreaders or at the mounting top or bottom.
2, Mast hits the water in a pitchpole ot wild gybe and breaks from the "impact" load
3, Mast is broken by the kite pulling it too far forward (loose mainsheet).
