On catamarans, a dagger-board simply slides up and down to adjust hieght. It does not retract if it contacts something. Daggerboards hitting bottom at high speeds are the cause of numerous pitchpoles and cracked hulls. When in the up position they stick out of the deck. Crews sitting behind the raised dagger-boards on a downwind run have broken ribs when the bows dug in and they were sent flying into the 'board.

Centerboards rotate to the down position. They are comparatively low-aspect, but can rotate upwards on contact. However, under heavy side-loads (typical upwind and reaching conditions) there is so much pressure on the board that it will not rotate easily. Still, they aren't nearly as likely to break the boat, and when in the up position they're contained within the hulls instead up sticking out of the deck.

The H16 has asymetrical hulls, which don't require boards of any type, but are not as efficient. H17s use centerboards and H18s use daggerboards. Getaways and similar designs use little skegs which do more to help the boat track straight than add windward performance. I'm not saying these boats can't go to windward, but they do so less effectively then the other types.

G-Cats have symetrical-yet-boardless hulls that still go to weather well, add no complexity to sailing, and dig into the sand on shore so much that cat-trax are a must for moving the boat any more than 20', even with two people.