MacGregorSailors.com

Nah can't see that working, not with the freeboard of a Mac in any sort of breeze or even a Kimberley tide think I have just about anchored under every condition (well maybe not every ) and everyone is different depending on where you are and how long you are staying.
Looks like only for little boats but some potential for modifying as an anchor spike with a line?

Some value of strength for the shaft would do the job, but I agree the 8' fiberglass rod is probably too flimsy. Stock 1/2" carbon fiber rod with a heavy brass spike compression fit at the bottom designed to slide through a 1/2" stainless tube on the stern would certainly do the job. Two joined lengths (10' total) of 1/2" CF cost <$100. Could use 1" (.995) for $200.

Just a thought. Not a need I have.