Small(ish) boat anchors

[jim j geezer]

Just happened across a site that's advertising a "new" kind of shallow water boat anchor. Seems a little pricey to me but I'd like to get some insight from folks who've actually used them. Instant observation: Looks to me like using these somewhere where there's waves from boat traffic would find disappointment. Also, a "hard"/rocky bottom would present an immediate problem.

http://dig-in-anchors.com/Power_Pole_Shallow_Water_Anchors/