Anchor
An anchor is a device, normally made of metal, used to connect a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin "ancora", which itself comes from the Greek ἄγκυρα ("ankura").
Offshore embedded anchors
Torpedo anchors feature a tubular steel pile, with or without vertical steel fins that are fitted with a conical tip and filled with scrap metal or concrete..  With heights of up to 150m, the anchor becomes completely buried within the seabed from free-fall. Full-scale field tests were performed in water depths of up to 1000m using a 762mm diameter, 12m long torpedo anchor with a dry weight of 400 kN. The torpedo anchor dropped from a height of 30m above the seabed achieved 29m in normally consolidated clay. Subsequent tests with a torpedo anchor, at 240 kN dry weight with an average tip embedment of 20m, resulted in capacities of approximately 4 times the anchor dry weight immediately following installation, which approximately doubled following 10 days of consolidation reaching an ultimate holding capacity of approximately 8 times the anchor dry weight. While the efficiencies are lower than what would be obtained with other sorts of anchor like a drag embedment anchor, this is compensated by the low cost of fabrication and ease of installation. Therefore, a series of torpedo anchors can be deployed for station-keeping of risers and other floating structures