Sea anchor
Modern commercial sea anchors are usually made of cloth, shaped like a parachute or cone, and rigged so that the wider end leads and the narrower end trails. When deployed, this type of sea anchor floats just under the surface, and the water moving past the sea anchor keeps it filled. Some varieties are cylindrical, with an adjustable opening in the rear that allows the amount of braking to be adjusted when deployed.
Anchor (climbing)
A natural anchor is a secure natural feature which can serve as a climbing anchor by attaching a sling, lanyard, or cordelette and a carabiner. Examples of natural anchors include trees, boulders, lodged chockstones, horns, icicles, and protrusions.