Good points. To be clear it is not really floating (at least I can't see it). When we brought the mast down the dolphin striker post pushed up 1/4 inch into the mast step cup.

The clamp will prevent upward motion of the post but will not prevent downward motion. It would have to be tremendous flex for the post to go down below the bar but I suppose its possible. Likewise it is doubtful that the clamp would help much since the mast exerts considerable downward pressure when it is raised. Thought about bolting the striker in the cup but it would compromise the depth of the cup.

I agree that replacing mast step is the solution. I appreciate your thoughts on this--it has helped me see some of the holes in my DIY bubble gum and baling wire thinking..