Embedding anchors in an underwater floor

A method of manufacturing a torpedo anchor, the method comprising:

• displacing a flowable cementitious material to form a cylindrical body and a plurality of fins, wherein:
• the cylindrical body has first and second ends and an exterior cylindrical surface, the cylindrical body comprising an interior cavity that extends through the cylindrical body between the first and second ends, the first and second ends comprising respective openings to the interior cavity, the interior cavity defining a conduit that is configured to contain a shaft, and
• the plurality of fins is disposed proximate the second end and extends outward from the exterior cylindrical surface, each fin formed at least in part of the flowable cementitious material;
• hardening the flowable cementitious material into a solidified cementitious material;
• and
• disposing a shaft through the conduit that comprises a shaft wall formed of a metal or metal alloy and defines an exterior shaft surface, the exterior shaft surface tapering into a tip at a nose end of the shaft, the tip configured to penetrate an underwater floor.