I think it's the inherent design that is faulty.
With the all or nothing system, if the water is any shallower then Max rudder draft then, without question you loose the steering and control of the boat.
You are talking about upper leg (or less) deep water here ! You really don't want to be sailing here.
When you run into such shallow water then the line system will disengage fully as well and you'll have exactly the same issues with respect to steerage.
I sailed with the line and kick-up cleat system for several years when I still was a cat sailing instructor and it is not my personal opinion that I was better off then in any way. As soon as you picked up speed the rudders would float up anyway.
And the trick with bungees pulling the boards down can be had with both systems. However these are also a good way to rid your sterns of your boat in a surf.
Wouter
