Not a problem with a catamaran! except if the skeg/rudder is as deep as the keel
, if the boat sheers sideways as it takes the ground there is a lot of force on the skeg/rudder.
Through hulls and impellors will get clogged.
fin keel may dig a hole eventually for the keel, but could also miss the hole with the keel and tip boat sideways into the hole!
keelers will also dig their own holes for the keels. Those bilge
keelers that tip their keels away from each other can suffer from hydraulic compression
where the forces at the hull/bilge keel are excessive and cause damage.
keel can get gravel into the keel box and jam the keel