Shaped like an inverted mushroom, this type of anchor relies on suction and cohesion to work. It can only work in fine sand-and-silt and mud bottoms. It buries itself in silt with the help of a counterweight at the other end of the shank. It sinks in the sand or silt until it displaces its own weight in bottom material.
Mushroom anchors can be as light as 10 pounds or as heavy as several tons.
A Danforth anchor has a stock at the crown where two large flat surfaces are attached. The stock is hinged to orient itself at the bottom. It sets itself in the seabed and develops a great amount of resistance.
Danforth anchors are easy to retrieve because of their lightweight and compact flat design.
A grapnel anchor is a non-burying anchor. It is made up of several tines. One or more tines dig and set into the seabed, while the remaining tines stay above. It is lightweight.
It is used to retrieving objects lost overboard. It can set quickly on corals but can be harder to retrieve.
Grapnel anchors rarely hold in sand, clay, or mud. It is difficult to stow because it is not compact.
A hall anchor is popularly used in smaller boats. It sets quickly in most seabeds and does not easily break due to tide or wind changes. It has claws for low rode scopes.
Hall anchors are not ideal for weedy bottoms and grass.
A Northill anchor is designed after the antique farm plow. It uses force and its shape to bury itself at the bottom.
Northill anchors can be used in most bottom conditions.