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
Until the mid-20th century, anchors for smaller vessels were either scaled-down versions of admiralty anchors, or simple grapnels. As new designs with greater holding-power-to-weight ratios, a great variety of anchor designs has emerged. Many of these designs are still under patent, and other types are best known by their original trademarked names.