These are made to work in mud and sand. They are perhaps the most common of all anchors available. The Pivoting Steel Fluke Anchor has two steel points that pivot and dig into the bottom.
This type is similar to Pivoting Steel Fluke Anchors, except the pointy part is actually stationary. These are good for holding your boat in rocks and weeds, and even sand also.
These they look like a big grappling hook. They are used with small boats when the water conditions are very mild.
They don't have a lot of holding power and they are generally used on skiffs, canoes, and inflatable boats.
They're used when we want to secure a boat to a beach.