As Chris says, one can sail the boat with the board deployed to different degrees. Not all keel-center boarders are created equally. Our Pearson 35 was a bit different from our Sabre 42. Aside from the hulls, the sailplans were very different. The Pearson depended on a relatively large foresail and the Pearson did not. So trimming with the "system was more critical with the Pearson, in my opinion.

In the case of the Irwin, I'm not sure what differences it would make.

II would be more carefull if you were sailing in gravel or course sand not to run aground with it deployed.