Good book, but old book. Are you familiar with the term "tripping on the keel"?
Paulo, I'm interested in this subject, only having had experience with full keels. Here is what I see, please go into a bit more detail if you see something else.
The drawing of the "tripping" on the keel looks like they are located where waves hit shallow water and break. An area we all try mightily to avoid. Seems that with a small keel or no keel the boat would be "flipping" instead of tripping. Not sure being tossed from the boat is better than filling the cockpit. Plus, trying to get some rest if the boat is rolling with the steepness of the wave fronts, that seems like it would be difficult.