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 Dam
Unfortunately the reservoir never filled. During construction, the discovery of solution cavities in the bedrock forced the re-positioning and re-configuration of the dam, causing delays and added expense. The same karst solution cavities prevented Anchor Reservoir from filling its design capacity of . It has never been full. More than 50 sinkholes had been identified in the underlying Chugwater Formation geology of the reservoir basin, with at least one of them 30 feet in diameter and 35 feet deep. The site's lack of "hydraulic integrity" was well known to Bureau scientists before and during construction.