Anybody use sandshark type anchor

[Toyelectroman]

Last year while anchoring at the local beach I noticed some boaters using a t-shaped post with what look like an auger fitting. Only thing I can find to buy was a sandshark anchor, but looked like some of the other boaters were homemade out of pvc. Anybody have any experience with these type of anchors? There was a lot of boats close to each other so I used a Danforth on the bow and a heavy mushrooms on the stern to make sure I didn't drift.

 

[Earl Cordova]

They won't work around here since the shore line is mostly rock.
But tying off to trees works well.