I was reliably informed by an iceyachter that this type of mast bending was the way that a DN iceyacht rides out the gustsand is unique to the DN. With a stiff mast they lift and tip too easily. the other iceyacht types dont do it this way as they have more wing like masts and rely on 'regular' twist to do the same thing. the DN type bend has really only been effective since the introduction of carbon masts. However , as Ive not seen a DN Itrust in his wealth of knowledge.
In the mid 80's when Bill and Bruce put stayed masts onto their class 6 yachts,combined with a springy rear axle, it was game over for every other class 6 that had come before.
They were simply little rockets . I believe they would have been competative against the current crop of Australian class 5 yachts.Adding a bit of 150mm alloy wing would make for extreme racing

even a cl5 chassis cant contain that combination. BUT the fleible rear axle is essential.
the next alternative is the tortional chassis. most chassis's ive seen here in Aus are too stiff at some point in the chassis, possibly because we use the 4.00x8 wheels with them . The Europeans learnt early on that tall,LIGHTWEIGHT rims and light tyres,on a OTT chassis, could replicate the effect of the wooden rear axles seen on the class3 yachts. combine this with the stiff tall masts that lay over just the right amount and you are replicating the powersystem of a winged mast ,springy axle combination that works so well.
heres a wing mast,stayed combination we put on a pacific magic,for fun

. it worked better when mounted on the bigger yacht 'Pigs Might Fly'