I just found out about this -- but it seems to be a great solution if it really works. I've never liked the idea of using a slotted anchor shaft, and a trip-line complicates deployment/retrieval and can be tripped by passing boats. This product seems to solve the problem and is priced reasonably. Gotta have it.

(I have no affiliation and this is not a spam post). http://www.anchorwitch.com/