Kick up Rudder - downhull?

https://www.owenclarkedesign.com/Twin-rudder-lifting-kick-up-steering-system-design
I read somewhere that the effectiveness is questionable. Why?

I saw that Mumby's cat had rudders with some kind of brake fail-safe kick up.

 

I understand the philosophy and in some instances it can led to breakthroughs but there is also the probability that an amount of time will be lost while re-inventing several wheels on the way to the new idea that does work.

Those IMOCA rudders can be lifted to clear debris,they are normally locked in place and it is normal for the windward rudder to be allowed to lift as it will be well clear of the water.They are superbly engineered in every respect.Without any lead getting involved.

 

It also precludes learning from other people's mistakes, which I submit are the best mistakes to learn from. For instance something I have witnessed more than once is a ballasted rudder/tiller assembly being dropped overboard, sinking and being lost. There is something particularly infuriating about the forlorn snatch that just fails to grab the item as it disappears beneath the waves.