It's a Manual Lock
Mark, In order for the keel to be locked in the down position, you have to manually engage the lock which is located inside to foward port settee, against the keel trunk. It really doesn't actually lock the keel in place, but rather puts tension on it, so that if you capsize, the keel won't slam into the housing, but would retract slowly, saving the boat from severe damaged. Some people choose not to engage this lock, which could have catastrophic consequences.